A Comprehensive Morphological, Biochemical, and Sensory Study of Traditional and Modern Apple Cultivars

Abstract

Apples (Malus domestica Borkh.) represent one of the most widely cultivated and consumed fruits globally, with significant genetic diversity among cultivars. This study aimed to evaluate the morphological, biochemical, and organoleptic characteristics of 34 apple cultivars, including ancient Romanian varieties, internationally old and modern cultivars, and new selections. The assessment was conducted to identify valuable traits for breeding programs and commercial applications. Morphological analysis revealed significant variation in fruit size, shape, and weight, with international ‘classic’ cultivars exhibiting larger dimensions on average. Biochemical profiling indicated notable differences in moisture content, total soluble solids, titratable acidity, and carotenoid levels, with some traditional cultivars demonstrating high nutritional potential. Texture analysis showed variations in peel hardness, flesh firmness, and toughness, influencing storage capacity and consumer preference. Organoleptic evaluations highlighted the superior sensory attributes of cultivars such as ‘Golden Orange’, ‘Jonathan’, ‘Kaltherer Böhmer’, and ‘Golden Delicious’, which ranked highest in terms of taste, aroma, and juiciness. Statistical analyses, including principal component and hierarchical clustering analyses, further distinguished cultivars based on their physicochemical and sensory profiles. The findings emphasize the importance of genetic diversity in apples in maintaining a resilient and sustainable assortment. This study provides valuable insights for breeding programs and for orchard, market, and apple industry development. We also highlight future directions, promoting the conservation and strategic use of both traditional and modern cultivars.

1. Introduction

Apples are the most widespread and consumed fruits in the temperate zone of the globe. The species Malus domestica Borkh. has been cultivated in Europe since ancient times, being well known to the Greeks and Romans [1,2]. From Europe and Asia, the apple has spread to almost all parts of the world, being currently cultivated in all areas where the species meets favorable growing conditions [3,4].

The apple tree is a popular cultivated tree due to its numerous advantages: easy cultivation and ecological and technological versatility, relatively easy maintenance of the trees, high fruit production per unit area, easy harvesting, handling, and transport of the fruits, the possibilities of long-term storage of the fruits, and multiple ways of capitalizing on the fruits [5,6,7]. Apples are a vital component of the human diet, offering significant health benefits linked to the prevention of various diseases [8,9,10,11]. Their nutritional profile, rich in carbohydrates (up to 90% dry matter), proteins (1.42–4.35%), fats (0.28–3.62%), and ash (1.32–2.08%), underscores their value [12,13]. Notably, apple peels exhibit antioxidant, antiproliferative, and lipid oxidation-inhibiting properties, contributing to reduced cholesterol levels. Scientific evidence highlights their role in lowering the risk of cancers (prostate, liver, colon, and lung), cardiovascular disease, asthma, Alzheimer’s, diabetes, obesity, and gastrointestinal disorders. Additionally, apples support pulmonary health, inhibit plaque aggregation, and reduce LDL cholesterol, further solidifying their importance in disease prevention [14,15,16,17,18,19].

There is an impressive number of apple cultivars, ensuring a varied varietal assortment, with staggered ripening from summer to autumn and the possibility of storing late-ripening fruits over the winter until the following year’s harvest [20,21]. Thus, the market is provided with fresh apples all the time [22]. The fruit can be eaten fresh as it is picked from the tree and throughout the year. Apples can be processed into sauce, slices, or juice and are preferred for pastries, cakes, tarts, and pies. The juice can be consumed fresh, either natural or filtered, fermented into alcoholic beverages such as cider, distilled into brandy, or made into vinegar [23].

Apples have become a symbol of health, with the proverb “An apple a day keeps the doctor away” being extremely popular in America and around the world [24,25,26]. In addition, apple pie has become a symbol of patriotism and national identity in America. This is because during World War II, soldiers famously claimed they were fighting for “mom and apple pie”. If apple pie has become a symbol of family and home for many Americans, in Romania, it is also associated with the symbol of childhood and the delicious pies and cakes prepared in grandma’s house. In Romania, the apple tree has a long and rich tradition with special symbolism [27], and the cultivation and breeding of the species have gone through three distinct stages. The first period marked the initiation of the improvement of fruit trees in Dacia (the ancient region where the Romanian people were later formed) and took place centuries or millennia before the colonization of Dacia by the Romans. At the time of the occupation of Dacia by the Roman legions, the local population knew and practiced, at a relatively high level, fruit growing, there being local varieties of apple trees, attested by archeological discoveries from the old Dacian fortresses [28].

The apple varieties brought by the Romans after the colonization of Dacia contributed to the diversification of cultivated forms. Even if empirical artificial selection was practiced in this first period, based on the observations and intuition of some anonymous fruit growers, some valuable local varieties and populations were obtained, some of which are maintained in culture (for example, ‘Crețesc’, ‘Domnesc’, ‘Patul’, ‘Poinic’ etc.) [29]. In Transylvania, the northwestern region of Romania, besides the unclear origin of some varieties, there are also etymological implications of different apple variety names. For example, the apples known as ‘Poinic’ (or ‘Ponic’) and ‘Patul’ in Romanian are known as ‘Pónyik’ and ‘Batul’, respectively, in Hungarian, and are equally claimed by Hungarian and Romanian pomologists [30]. The second period began in the middle of the 19th century and lasted until the end of the first two or three decades of the 20th century. Since many of the old varieties no longer met the increasingly high requirements for productivity and quality, new varieties were brought from Western countries where apple breeding was more advanced. That is why the period was called an age of ‘massive imports’, and among the apple varieties that entered Romania were also varieties that are very well known worldwide, such as ‘Jonathan’, ‘Parmen auriu’ (‘Pearmain’), ‘London Pepping’, ‘James Grieve’, ‘Belle de Boskoop’, ‘Cox’s Orange Pippin’, ‘Golden Delicious’, ‘Kaltherer Böhmer’, ‘Reinette’, ‘Wagener premiat’, etc. Many of these varieties were spread and cultivated in different regions, being known over time under different names. Among the several synonyms and homonyms of ‘Kaltherer Böhmer’ (for example, ‘Apfel aus Mantua’, ‘Böhmer von Kaltern’, ‘Kalterer’, ‘Mantua’, ‘Mantuaner’, ‘Mantovano’, ‘Rosa Mantovano’), at least three or four were used in Transylvania [29]. In addition to the important contribution of these varieties to the increase in horticultural production in Romania, they also had a positive influence on the development of apple breeding activities in Romania. Through their exceptional genetic fund, they made a significant contribution to the results obtained in apple breeding in the third stage, considered the “modern stage” [31,32]. This last stage began chronologically in 1928, when the Romanian Agronomic Research Institute (I.C.A.R.) was established and apple breeding developed on a deeply scientific basis. Germplasm collection fields were established, and the accumulated genetic resources were used to create new varieties, especially through artificial hybridization. Old, native local varieties and populations, as well as varieties imported from abroad, have had a significant role in Romania as parental forms in hybridization and in causing genetic variability, necessary for the creation of new varieties. In addition, some still have a significant share in the cultivated assortment today. As a germplasm fund, they constitute a particularly valuable reserve for new breeding research.

The existence and in-depth knowledge of the genetic variability in apple trees further offer the prospect of obtaining and selecting types that are adapted to different pedoclimatic and cultural conditions [33,34]. New varieties must be suitable and adequate for different destinations and technological conditions of cultivation, as well as their economic and social requirements, but also to climatic changes and assortment preferences among apple consumers and the profile industries that process and use fruits and fruit products for different purposes [35,36,37]. To achieve these objectives, particularly in modern apple breeding, research has concentrated on specific goals related to the suitability of fruits for particular applications, such as industrial processing into juices, the development of disease-resistant varieties, adaptation to various ecological conditions across different climates, etc. [38,39,40]. The protracted duration necessary for the transfer of a resistance gene from a wild species to a cultivated varieties (such as the transfer of the gene originally called Vf from Malus floribunda 821 to the first variety considered resistant due to this gene, ‘Prima’) through successive hybridization and generations of selection (beginning earlier than 1910 and completing in 1970) exemplifies the challenges and complexities inherent in plant breeding processes [41,42,43]. The reduced resistance conferred by this gene, which new physiological phytopathogens of Venturia inaequalis suppress, illustrates the challenges faced by plant breeders [44,45].

Throughout the history of apple breeding, regardless of the specific objectives or the era in which the work was conducted, fruit quality has consistently remained a central focus [46,47,48]. Extensive research has been dedicated to assessing fruit quality, with numerous methods developed to conduct sensory analyses. However, sensory evaluation inherently involves a degree of subjectivity, being influenced by the individual preferences of tasters, the methodologies employed, and the condition of the samples during assessment [49]. To mitigate these challenges, standardized procedures have been established to ensure the identification and promotion of high-quality varieties. These methods also help to discern consumer preferences and emerging market trends, guiding breeding efforts toward the development of improved varieties that meet both the demands and expectations of consumers [50,51]. By aligning breeding objectives with market needs, these practices contribute to the production and distribution of superior-quality fruits that satisfy consumer desires.

Based on these considerations, the present study aimed to conduct detailed analysis of some morphological and biochemical characteristics of the fruits of different apple varieties. These were represented by old Romanian varieties, which still exist in the cultivated assortment in Romania, as well as varieties from the international assortment that are well known and widespread around the world. Of these, some were represented by old varieties obtained before the 20th century, while others were relatively new varieties, considered ‘modern’, but were well rated in the world assortment. The analysis aimed both to identify the variability within these cultivars in order to use those appropriate for modern breeding objectives in new artificial hybridizations, and to recommend their continued use in cultivation. The study also aimed to compare varieties, categorized by origin and age, to ascertain whether advanced breeding has enhanced the morphological features of fruit or the chemical composition of modern apple varieties, potentially contributing to their commercial and nutritional value or organoleptic quality.

2. Materials and Methods

2.1. Biological Material

The biological material was represented by 34 apple cultivars (Figure 1), some of which were Romanian varieties. Others were from the international assortment, and several selections were obtained as a result of the breeding process. In the present study, the cultivars, sometimes referred to as genotypes or varieties, were categorized into four groups. Consequently, 5 were categorized as Romanian varieties, regarded as ancient autochthonous types originating from the empirical phase of apple breeding; 13 were represented by international varieties developed prior to the 20th century, all of which are well recognized and extensively distributed globally; 13 were international modern cultivars; and 3 genotypes were represented by recent apple selections resulting from the breeding process in Romania. Only the first three groups were considered in this study because the final group, which only comprised three selections, was only included for possible comparisons.

2.2. The Conditions Under Which the Fruits Used as Biological Material Were Obtained

The apples of cultivars used in the experiments were taken from the Research Institute for Fruit Growing’s germplasm collection at Pitești-Mărăcineni (RIFGPM), Romania (44.8992° N latitude and 24.8596° E longitude). With an average temperature of 9.8 °C and 668 mm of precipitation per year, the climate in the RIFGPM area is excellent for the cultivation of fruit species. Situated 262 m above sea level on colluvial and alluvial soil with a medium humus content, the experimental apple collection of RIFGPM, which includes over 600 apple cultivars, is close to the institute’s headquarters. The apple orchard was started in 2010 at a density of 1000 trees per hectare, with all cultivars being grafted onto the rootstock MM106. The trees were planted 4 m between rows and 2.5 m between trees (4 × 2.5 m), resulting in a density of 1000 trees/ha. Standard methods, comparable to those used in commercial orchards, were utilized for fertilization, phytosanitary treatments, and tree upkeep.

2.3. Analyses Performed on Fruits

To assess fruit qualities, we extracted 90 fruits per genotype in an aleatory fashion from a mass of fruits harvested at the BBCH-87 phenological stage. All fruits were free of diseases, pests, and mechanical damage. The fruit tests were did in the lab, with five repetitions per genotype. Fruit morphological measurements and analyses were performed based on standard procedures, as described previously [36]. Employing a vernier caliper and the technique outlined by Mohsenin [52], we assessed the fruit dimensions of various apple genotypes included in the study. The oven-drying technique was employed to ascertain the moisture content of the apple sample at 103 °C ± 2 °C until its weight stabilized. A muffle furnace was employed to ash the apple samples at 600 °C to assess the mineral content. We employed the standard refractometric method ISO 2173:2003 to ascertain the total soluble solids, and the ISO 750:1998 (E) method to assess the titratable acidity. The apple samples were assessed for color, utilizing the CIE L* a* b* color space with an NR200 portable colorimeter (3NH, Shenzhen, China). A stainless steel TA39 probe (2 mm diameter rod, 20 mm length, flat end) with a 5 g mass was employed in a CT3 Brookfield Texture Analyzer for texture analysis. The hardness work (mJ), peel hardness (N), toughness (mm), and flesh hardness (N) were assessed utilizing the procedures outlined by Qiu et al. [53] and Bejaei et al. [54], although with a few adjustments proposed by Muresan et al. [36].

2.4. Organoleptic Evaluation of Fruits

The organoleptic assessment of the fruits was conducted via tasting trials, using sheets called “Bulletin for assessing the organoleptic quality of fruits” (Figure 2) [55], with different scoring scales used for sensorial traits, rating fruit between minimum (extremely disliked) and maximum (extremely liked) positions. The tests were conducted with 20 participants (nonspecialists in the field), evenly divided between women and men. The evaluations were conducted at the optimum period for fruit consumption, when maturity guaranteed perfect conditions for assessing both the exterior appearance and inherent features of the fruits. Tasting sheets were utilized to record data on the outward appearance of the fruits and their fundamental features. Three main attributes that contribute to the commercial appeal of fruits have been determined: size, shape, and color. The evaluation scale for the initial two traits ranged from 1 to 3, while the assessment of fruit color spanned from 1 to 5. The intrinsic attributes of the fruits were determined as pulp color, consistency, juiciness, taste, and aroma (flavor). Pulp or flesh color and consistency were evaluated on a scale from 1 to 3, juiciness and aroma were assessed in a range from 1 to 5, and taste was placed on a scale from 1 to 15. Low ratings were assigned when negative factors predominated, and high scores, reaching the maximum, were awarded when positive factors prevailed.

Tasting reports were used that had scores with differentiated evaluation scales between 3 and 15 points to account for the estimated rate or contribution of each characteristic to the overall fruit quality. This was based on a previous study of the organoleptic quality of apples [55]. When evaluating the particularities of interest for the overall fruit quality, differentiated scales were preferred to standard sheets in which the same fruit traits were scored on a common hedonic scale from 1 to 9. The tasters received succinct instructions before evaluation, including an explanation of the grading scale and procedure used for each characteristic. They were instructed to assign individual grades without engaging in conversation, depending on their assessment or satisfaction with each evaluated cultivar and attribute. The tasters were instructed to refrain from eating for a minimum of two hours before the tastings. Each taster received two fruits from each genotype, one of which was cut along the axis into four pieces for internal analysis and tasting. Water and pieces of white bread were provided between trials to adjust the taste. The identity of the sampled cultivars was concealed, with each specimen assessed using an anonymous identification.

2.5. Statistical Analyses

To provide an overview of the main morphological and biochemical characteristics of the fruits of the apple genotypes, the final data were processed as mean values for the most important characteristics analyzed (mean ± SEM; SEM, standard error of the mean). In order to identify possible differences between the means of the analyzed parameters, analysis of variance (ANOVA) was used as a statistical test. When the null hypothesis was rejected, ANOVA was completed with Duncan’s test (α < 0.05) as a post hoc test to separate and highlight the differences among means. Boxplots were used to compare genotypes, which were divided into three groups (autochthonous, old Romanian cultivars; international ‘classic’, old cultivars; international modern cultivars), with each demonstrating the minimum values, the lower, median, upper quartiles, and the maximum values of the parameters per group.

Multivariate analyses were performed after data normalization. Pearson correlations (simple phenotypic correlations) were calculated using PAST software (PAleontological STatistics (PAST) Version 4.09, Natural History Museum, University of Oslo, Oslo Norway) [56]. The same software was used to perform principal component analysis (PCA) and hierarchical clustering analyses using the single linkage method and Gover similarity index.

3. Results

3.1. Physicochemical Properties of Fruits

According to the data in

Table 1. The main morphological traits of the fruits from 34 apple cultivars, categorized into four groups.

No *	Cultivar	Fruit Height (mm)	Fruit Width (mm)	Fruit Shape Index	Fruit Weight (g)	Fruit Volume (mL)
1	‘Crețesc Auriu’	45.8 ± 4.2 cd	61.1 ± 4.5 c	0.75 ± 0.15 f	172.1 ± 32.9 d	236.3 ± 37.5 bc
2	‘Domnesc’	45.0 ± 5.1 cd	61.3 ± 7.2 c	0.73 ± 0.08 f	159.2 ± 41.0 d	232.5 ± 55.2 bc
3	‘Patul’	39.4 ± 4.6 e	43.7 ± 2.9 f	0.90 ± 0.12 c	92.8 ± 17.7 g	113.8 ± 22.1 g
4	‘Poinic’	51.5 ± 8.3 bc	57.1 ± 3.4 d	0.90 ± 0.20 c	161.8 ± 27.4 d	217.5 ± 30.7 c
5	‘Sovari’	54.0 ± 6.7 b	65.1 ± 7.9 b	0.83 ± 0.11 d	212.9 ± 50.3 b	268.8 ± 60.5 b
6	‘Belle de Boskoop’	22.6 ± 9.3 g	30.5 ± 13.0 g	0.74 ± 0.12 f	202.2 ± 77.2 bc	252.5 ± 95.5 bc
7	‘Cox’s Orange Pippin’	38.1 ± 4.0 e	48.8 ± 6.5 e	0.78 ± 0.03 e	127.8 ± 16.7 f	166.3 ± 23.9 e
8	‘Golden Delicious’	50.5 ± 4.4 bc	55.4 ± 3.5 d	0.91 ± 0.14 c	165.2 ± 16.6 d	202.5 ± 18.5 c
9	‘Grimes Golden’	48.5 ± 4.6 c	57.0 ± 2.5 d	0.85 ± 0.09 d	167.7 ± 20.2 d	222.5 ± 24.7 bc
10	‘James Grieve’	45.5 ± 3.1 cd	54.1 ± 4.8 d	0.84 ± 0.12 d	143.3 ± 16.0 ef	190.0 ± 29.4 cd
11	‘Jonathan’	58.7 ± 2.2 a	69.3 ± 2.3 a	0.85 ± 0.11 d	176.3 ± 16.5 cd	235.0 ± 20.8 bc
12	‘Kaltherer Böhmer’	54.3 ± 3.6 b	60.9 ± 4.8 c	0.89 ± 0.12 c	192.1 ± 33.3 c	262.5 ± 37.5 b
13	‘Pearmain’	40.4 ± 3.9 e	52.8 ± 3.6 d	0.77 ± 0.22 e	148.1 ± 27.8 e	195.0 ± 42.0 cd
14	‘Reinette de Champagne’	46.5 ± 6.5 cg	58.8 ± 10.3 cd	0.79 ± 0.11 e	179.1 ± 54.4 c	225.0 ± 66.1 c
15	‘Reinette Harbert’	49.3 ± 3.6 bc	61.3 ± 5.9 c	0.80 ± 0.21 d	182.8 ± 36.6 c	240.0 ± 39.2 bc
16	‘Reinette Osnabruck’	55.0 ± 3.1 ab	66.1 ± 3.2 b	0.83 ± 0.14 d	182.4 ± 32.5 c	248.8 ± 43.6 bc
17	‘Reinette du Canada’	52.8 ± 5.7 b	69.7 ± 8.5 a	0.76 ± 0.15 ef	243.9 ± 52.6 a	335.0 ± 71.3 a
18	‘Wagener’	45.0 ± 3.5 d	59.1 ± 3.1 c	0.76 ± 0.11 ef	170.8 ± 29.5 cd	201.3 ± 22.5 c
19	‘Baujade’	42.2 ± 2.7 de	52.8 ± 2.9 d	0.80 ± 0.20 d	139.8 ± 16.7 ef	180.0 ± 21.6 d
20	‘Champion’	45.7 ± 5.6 cd	60.1 ± 6.4 c	0.76 ± 0.12 ef	165.7 ± 38.2 cd	210.0 ± 49.2 c
21	‘Elstar’	39.9 ± 2.8 e	54.0 ± 2.3 d	0.74 ± 0.09 f	132.5 ± 11.7 ef	181.3 ± 16.0 d
22	‘Enterprise’	50.1 ± 5.5 bc	58.6 ± 6.1 c	0.85 ± 0.08 d	187.7 ± 29.7 c	236.3 ± 54.4 bc
23	‘Florina’	52.5 ± 4.8 c	58.8 ± 6.1 c	0.89 ± 0.11 c	185.4 ± 35.7 c	240.0 ± 47.3 bc
24	‘Golden Orange’	55.8 ± 0.8 a	66.4 ± 2.6 b	0.84 ± 0.12 d	245.9 ± 12.3 a	323.8 ± 18.4 a
25	‘Goldrush’	49.8 ± 4.9 bc	52.8 ± 4.4 d	0.94 ± 0.10 b	152.3 ± 23.3 e	252.5 ± 35.0 b
26	‘Granny Smith’	53.0 ± 6.4 ab	58.3 ± 5.3 c	0.91 ± 0.24 c	183.6 ± 42.0 c	238.8 ± 58.5 bc
27	‘Judor’	40.7 ± 2.2 e	49.5 ± 6.3 de	0.82 ± 0.12 d	113.9 ± 14.4 f	161.3 ± 26.6 e
28	‘Juliana’	31.6 ± 4.6 f	42.7 ± 5.5 f	0.74 ± 0.11 f	75.6 ± 14.8 h	100.0 ± 20.4 g
29	‘Jurella’	32.6 ± 3.6 f	44.4 ± 3.9 f	0.73 ± 0.13 f	93.6 ± 18.5 g	132.5 ± 25.3 f
30	‘Red Delicious Redkan’	54.8 ± 5.5 ab	66.1 ± 6.0 b	0.83 ± 0.20 d	209.5 ± 37.8 b	255.0 ± 48.1 b
31	‘Sir Prize’	56.9 ± 2.2 a	53.3 ± 4.4 d	1.07 ± 0.30 a	156.9 ± 25.5 e	210.0 ± 37.0 c
32	‘T107’	49.8 ± 4.7 bc	55.8 ± 5.2 cd	0.89 ± 0.21 c	157.4 ± 32.8 e	206.3 ± 37.9 c
33	‘T194’	49.5 ± 4.3 bc	59.1 ± 3.9 c	0.84 ± 0.11 d	182.7 ± 32.4 c	215.0 ± 43.4 c
34	‘T195’	41.2 ± 4.0 e	53.8 ± 7.3 d	0.77 ± 0.14 ef	125.4 ± 29.0 f	180.0 ± 43.2 d

* 1–5: autochthonous (Romanian) cultivars; 6–18: international ’classic’ (old) cultivars; 19–31: international modern cultivars; 32–34: new selections. According to Duncan’s test (α < 0.05), there is no significant difference between any two means in a column when followed by the same letter for each trait.

, for the main morphological characteristics of the fruits, there were significant differences between the cultivars analyzed. The height of the fruits oscillated across the 34 cultivars between 22.6 and 58.7 mm. The cultivars with the highest values in terms of the characteristics were as follows: ‘Jonathan’, ‘Sir Prize’ and ‘Golden Orange’. At the opposite pole, the cultivars ‘Belle de Boskoop’, ‘Juliana’, and ‘Jurella’ were situated. The fruits with the largest width (diameter) were recorded in the cultivars ‘Reinette du Canada’, Jonathan, and ‘Golden Orange’. Significantly lower values were recorded compared to most cultivars for ‘Belle de Boskoop’, ‘Juliana’, and ‘Patul’. For the fruit shape index, relatively few cultivars had values close to 1, reflecting a fruit shape close to spherical or round (i.e., ‘Sir Prize’, with 1.07; ‘Goldrush’, 0.94; ‘Golden Delicious’ and ‘Granny Smith’, 0.91; ‘Poinic’ and ‘Patul’, 0.90). For all cultivars, the trait values ranged between 0.73 and 1.07. Most varieties had flattened spherical fruits, with the most flattened fruits being recorded as ‘Domnesc’, ‘Jurella’, ‘Elstar’, Julianna, and ‘Belle de Boskoop’.

Fruit weight varied greatly among the genotypes analyzed, with the limits ranging between 75.6 and 245.9 g. The heaviest fruits were recorded for the following cultivars: ‘Golden Orange’, ‘Reinette du Canada’, ‘Sovari’, and ‘Red Delicious Redkan’. In contrast, the cultivars ‘Juliana’, ‘Patul’, and ‘Jurella’ had low fruit weights. The amplitude of variation for fruit volume was large, with the lower limit of the characteristic being recorded for ‘Juliana’ (100 mL), while the upper limit was obtained for ‘Reinette du Canada’ (335 mL). The average values of the morphological traits of the fruits in 34 varieties were as follows: fruit height—46.7 mm; fruit width—56.4 mm; fruit shape index—0.83; fruit weight—164.4 g; fruit volume—216.7 mL.

Considerable variation was observed among cultivars regarding key attributes in fruit skin and texture, such as peel hardness, toughness, flesh hardness, and overall hardness (

Table 2. The main traits of the peel and fruit texture of 34 apple cultivars categorized into four groups.

No *	Cultivar	Peel Hardness (N)	Toughness (mm)	Flesh Hardness (N)	Hardness Work (mJ)
1	‘Crețesc Auriu’	9.8 ± 1.4 e	1.6 ± 0.2 c	2.4 ± 0.3 e	17.8 ± 1.4 e
2	‘Domnesc’	7.7 ± 1.0 f	1.5 ± 0.3 cd	2.1 ± 0.3 e	15.3 ± 0.8 ef
3	‘Patul’	11.5 ± 1.2 d	1.2 ± 0.2 f	3.6 ± 0.4 c	21.2 ± 1.8 d
4	‘Poinic’	9.1 ± 0.8 e	1.3 ± 0.2 e	3.0 ± 0.4 cd	16.9 ± 1.4 e
5	‘Sovari’	7.7 ± 1.1 f	1.2 ± 0.2 f	2.0 ± 0.1 ef	13.7 ± 1.4 f
6	‘Belle de Boskoop’	12.3 ± 1.0 cd	2.1 ± 0.5 a	5.5 ± 0.9 a	31.2 ± 2.1 a
7	‘Cox’s Orange Pippin’	10.6 ± 1.7 e	1.5 ± 0.2 cd	2.3 ± 0.9 e	18.1 ± 5.0 e
8	‘Golden Delicious’	9.9 ± 0.7 e	1.1 ± 0.1 g	3.8 ± 0.9 c	22.3 ± 3.3 d
9	‘Grimes Golden’	8.5 ± 0.8 e	1.3 ± 0.2 e	2.1 ± 0.5 e	14.8 ± 1.5 ef
10	‘James Grieve’	5.8 ± 2.4 g	1.7 ± 0.5 b	1.2 ± 0.7 g	10.2 ± 4.3 g
11	‘Jonathan’	6.8 ± 0.2 fg	1.3 ± 0.1 e	2.1 ± 0.5 ef	13.8 ± 2.2 f
12	‘Kaltherer Böhmer’	11.8 ± 1.2 d	1.8 ± 0.4 b	3.5 ± 0.4 c	22.7 ± 1.2 cd
13	‘Pearmain’	7.2 ± 0.4 f	1.1 ± 0.3 g	2.8 ± 0.5 d	16.7 ± 2.3 e
14	‘Reinette de Champagne’	11.3 ± 1.7 d	1.2 ± 0.1 f	3.7 ± 0.3 c	24.1 ± 0.9 cd
15	‘Reinette Harbert’	8.9 ± 2.0 ef	1.4 ± 0.2 d	3.0 ± 0.3 d	18.5 ± 3.0 e
16	‘Reinette Osnabruck’	8.6 ± 0.7 ef	1.2 ± 0.2 f	4.5 ± 0.4 b	24.9 ± 0.8 c
17	‘Reinette du Canada’	11.6 ± 1.9 d	1.7 ± 0.5 b	3.2 ± 1.7 cd	20.8 ± 5.7 d
18	‘Wagener’	12.9 ± 0.7 c	1.4 ± 0.1 d	3.2 ± 0.9 cd	21.6 ± 2.7 cd
19	‘Baujade’	16.9 ± 1.2 a	1.6 ± 0.1 c	4.0 ± 0.5 c	27.8 ± 1.8 b
20	‘Champion’	13.7 ± 1.1 c	1.6 ± 0.2 c	3.2 ± 0.3 cd	23.5 ± 1.9 cd
21	‘Elstar’	6.2 ± 2.0 fg	1.2 ± 0.2 f	1.5 ± 0.4 fg	11.0 ± 2.8 g
22	‘Enterprise’	11.0 ± 0.7 d	1.5 ± 0.1 cd	2.5 ± 0.5 e	18.6 ± 1.4 e
23	‘Florina’	10.1 ± 0.9 e	1.3 ± 0.1 e	2.0 ± 0.1 ef	16.1 ± 0.7 e
24	‘Golden Orange’	8.2 ± 1.2 ef	1.4 ± 0.2 d	2.0 ± 0.4 ef	14.5 ± 1.6 ef
25	‘Goldrush’	10.7 ± 2.3 de	1.3 ± 0.2 e	3.4 ± 0.8 c	21.2 ± 4.1 d
26	‘Granny Smith’	12.8 ± 2.1 cd	1.7 ± 0.4 b	3.1 ± 0.4 cd	23.3 ± 1.5 cd
27	‘Judor’	7.1 ± 1.1 f	1.1 ± 0.1 g	2.0 ± 0.1 ef	14.1 ± 0.4 f
28	‘Juliana’	9.6 ± 0.8 e	1.6 ± 0.2 c	3.0 ± 0.4 cd	19.8 ± 1.6 de
29	‘Jurella’	14.9 ± 0.4 b	1.2 ± 0.2 f	4.6 ± 0.7 b	28.1 ± 1.8 b
30	‘Red Delicious Redkan’	11.9 ± 1.0 d	1.3 ± 0.1 e	2.9 ± 0.3 cd	20.2 ± 0.3 de
31	‘Sir Prize’	7.7 ± 0.6 f	1.3 ± 0.1 e	1.6 ± 0.4 f	12.6 ± 1.3 f
32	‘T107’	9.7 ± 1.2 e	1.5 ± 0.2 cd	3.1 ± 0.7 cd	20.0 ± 2.4 de
33	‘T194’	10.7 ± 0.9 de	1.1 ± 0.1 g	2.3 ± 0.3 e	17.0 ± 2.0 e
34	‘T195’	7.8 ± 1.0 f	1.3 ± 0.2 e	2.5 ± 0.9 e	15.5 ± 1.4 ef

* 1–5: autochthonous (Romanian) cultivars; 6–18: international ’classic’ (old) cultivars; 19–31: international modern cultivars; 32–34: new selections. Working according to Duncan’s test (α < 0.05), there is no significant difference between any two means in a column when followed by the same letter for each trait.

). The average values of these traits were as follows: peel hardness—10.0 N; toughness—1.4 mm; flesh hardness—2.9 N; hardness work—19 mJ. The extreme values of peel hardness ranged between 5.8 and 16.9 N. The varieties recording the highest values in the trait were ‘Baujade’, ‘Jurella’, and ‘Champion’, while the varieties with the lowest values were ‘James Grieve’ and ‘Elstar’. The limits of variation for toughness ranged between 1.1 and 2.1 mm, with the cultivars with the highest values being ‘Belle de Boskoop’ and ‘Kaltherer Böhmer’. At the opposite pole were ‘T194’, ‘Golden Delicious’, and ‘Judor’.

Among the varieties tested, the highest level of fruit flesh hardness was identified in ‘Belle de Boskoop’ and ‘Jurella’. In contrast to these, the values of ‘James Grieve’ and ‘Elstar’ were recorded. The flesh hardness had a relatively wide amplitude among the varieties tested, with the lower limit being 1.2 N and the upper limit being 5.5 N. For hardness work, the variation in traits among the analyzed genotypes was between 10.2 and 31.2 mJ; the varieties with the highest values were ‘Belle de Boskoop’ and ‘Jurella’. Lower hardness values were recorded in the following varieties: ‘James Grieve’, ‘Elstar’ and ‘Sir Prize’.

The average value of the fruits’ moisture throughout all genotypes was 84.2%, and the limits of variation within the 34 cultivars ranged between 79.3% and 89.5% (

Table 3. The main chemical characteristics of the fruits of 34 apple cultivars, categorized into four groups.

No *	Cultivar	Moisture (%)	Ash Content (%)	TSS ** (%)	TA *** (%)	Carotenoids (mg/100 g)
1	‘Crețesc Auriu’	86.3 ± 0.8 b	0.82 ± 0.2 d	12.4 ± 0.2 f	0.49 ± 0.01 cd	3.00 ± 0.08 d
2	‘Domnesc’	82.9 ± 0.4 d	0.32 ± 0.0 f	15.3 ± 0.2 de	0.45 ± 0.03 cd	1.70 ± 0.03 f
3	‘Patul’	82.2 ± 0.8 de	0.54 ± 0.4 e	15.9 ± 0.5 d	0.68 ± 0.20 c	1.60 ± 0.00 f
4	‘Poinic’	82.6 ± 0.3 d	0.37 ± 0.0 ef	14.8 ± 0.1 e	0.22 ± 0.01 e	0.79 ± 0.03 g
5	‘Sovari’	86.2 ± 0.1 b	0.72 ± 0.0 d	14.5 ± 0.7 e	0.21 ± 0.01 e	2.60 ± 0.01 de
6	‘Belle de Boskoop’	80.9 ± 0.1 e	1.40 ± 0.3 c	17.7 ± 0.4 c	0.92 ± 0.07 b	1.40 ± 0.03 f
7	‘Cox’s Orange Pippin’	84.6 ± 0.2 c	0.50 ± 0.4 e	18.6 ± 0.6 b	0.37 ± 0.01 d	1.70 ± 0.01 f
8	‘Golden Delicious’	81.2 ± 0.6 de	0.31 ± 0.0 ef	17.1 ± 0.5 c	0.46 ± 0.01 cd	1.40 ± 0.01 f
9	‘Grimes Golden’	83.9 ± 0.1 c	0.43 ± 0.0 e	14.9 ± 1.1 de	0.34 ± 0.00 d	2.10 ± 0.01 e
10	‘James Grieve’	79.3 ± 0.0 f	1.86 ± 0.4 b	20.7 ± 1.3 a	0.51 ± 0.04 cd	1.10 ± 0.04 fg
11	‘Jonathan’	85.3 ± 0.2 c	0.58 ± 0.0 e	15.0 ± 0.7 de	0.40 ± 0.06 d	1.50 ± 0.01 f
12	‘Kaltherer Böhmer’	83.9 ± 0.6 c	0.30 ± 0.1 ef	14.5 ± 0.7 e	0.40 ± 0.01 d	1.20 ± 0.08 fg
13	‘Pearmain’	80.4 ± 0.3 e	2.25 ± 0.4 a	18.4 ± 0.4 b	0.41 ± 0.05 d	1.40 ± 0.00 f
14	‘Reinette de Champagne’	86.2 ± 0.4 b	0.60 ± 0.0 e	12.4 ± 0.1 f	0.34 ± 0.01 d	6.60 ± 0.010 a
15	‘Reinette Harbert’	87.0 ± 0.2 b	0.81 ± 0.1 d	14.2 ± 0.8 e	0.54 ± 0.04 cd	2.50 ± 0.04 e
16	‘Reinette Osnabruck’	82.8 ± 0.4 d	0.91 ± 0.0 d	14.0 ± 0.1 e	1.16 ± 0.02 a	2.50 ± 0.02 e
17	‘Reinette du Canada’	81.4 ± 0.3 e	1.68 ± 0.3 bc	15.5 ± 0.2 d	0.56 ± 0.03 cd	2.60 ± 0.02 e
18	‘Wagener’	86.3 ± 0.5 b	0.22 ± 0.1 f	17.4 ± 1.9 c	0.40 ± 0.04 d	1.90 ± 0.01 f
19	‘Baujade’	88.3 ± 0.0 ab	1.34 ± 0.0 c	10.6 ± 0.5 h	0.62 ± 0.00 c	4.60 ± 0.04 b
20	‘Champion’	80.7 ± 0.7 e	0.57 ± 0.1 e	16.8 ± 1.2 c	0.36 ± 0.01 d	1.10 ± 0.01 g
21	‘Elstar’	85.3 ± 0.3 c	0.50 ± 0.0 e	18.9 ± 2.7 b	0.43 ± 0.02 d	0.61 ± 0.11 g
22	‘Enterprise’	82.4 ± 0.5 d	0.51 ± 0.3 e	14.1 ± 0.1 e	0.34 ± 0.01 d	2.60 ± 0.05 de
23	‘Florina’	84.9 ± 0.0 c	1.50 ± 0.1 c	17.4 ± 1.9 c	0.34 ± 0.02 d	1.70 ± 0.06 f
24	‘Golden Orange’	82.9 ± 0.4 d	0.63 ± 0.0 e	17.1 ± 2.4 c	0.41 ± 0.01 d	1.10 ± 0.01 g
25	‘Goldrush’	86.2 ± 0.1 b	0.17 ± 0.0 f	13.2 ± 0.3 f	0.36 ± 0.02 d	1.30 ± 0.01 f
26	‘Granny Smith’	86.9 ± 0.0 b	0.51 ± 0.0 e	11.8 ± 0.3 g	0.50 ± 0.01 d	2.80 ± 0.09 de
27	‘Judor’	82.5 ± 0.9 d	0.60 ± 0.2 e	19.9 ± 1.1 a	0.62 ± 0.04 c	0.35 ± 0.02 g
28	‘Juliana’	80.6 ± 0.7 e	1.61 ± 0.6 bc	19.4 ± 0.3 ab	0.71 ± 0.02 c	2.20 ± 0.00 e
29	‘Jurella’	89.5 ± 0.3 a	0.34 ± 0.2 ef	13.4 ± 0.1 f	0.64 ± 0.04 c	2.00 ± 0.01 ef
30	‘Red Delicious Redkan’	85.2 ± 0.4 c	0.53 ± 0.0 e	15.0 ± 0.3 d	0.20 ± 0.02 e	1.40 ± 0.08 f
31	‘Sir Prize’	88.8 ± 0.4 a	0.94 ± 0.3 d	12.8 ± 0.5 fg	1.10 ± 0.04 a	3.80 ± 0.01 c
32	‘T107’	83.2 ± 0.5 d	1.78 ± 1.1 b	15.1 ± 0.3 d	0.42 ± 0.01 d	0.67 ± 0.01 g
33	‘T194’	85.2 ± 0.7 c	0.82 ± 0.3 d	17.8 ± 0.6 bc	0.30 ± 0.01 de	2.50 ± 0.05 de
34	‘T195’	87.6 ± 0.7 b	0.05 ± 0.0 g	13.5 ± 1.1 f	0.21 ± 0.01 e	0.70 ± 0.01 g

* 1–5: autochthonous (Romanian) cultivars; 6–18: international ‘classic’ (old) cultivars; 19–31: international modern cultivars; 32–34: new selections. ** total soluble solids (%). *** titratable acidity (% malic acid). According to Duncan’s test (α < 0.05), there is no significant difference between any two means in a column when followed by the same letter for each trait.

). The maximum limit was recorded for ‘Jurella’, followed closely by ‘Sir Prize’ and ‘Baujade’. The lower moisture value was presented by ‘James Grieve’, and values close to it were also presented by ‘Pearmain’ and ‘Juliana’. The ash content of the fruits was between 0.05 and 2.25%, with the average of all genotypes being 0.8%. Genotypes ‘Pearmain’, ‘James Grieve’, and ‘T107’ stood out for the high ash content of the fruits. At the other extreme were genotypes ‘T195’, ‘Goldrush’, and ‘Wagener’, which had the fruits with the lowest ash content. The content of total soluble substances in the fruits varied quite widely, in a range between 10.6 and 20.7%. ‘James Grieve’, ‘Judor’ and ‘Juliana’ were distinguished by a rich content in total soluble substances. On the contrary, ‘Baujade’ and ‘Granny Smith’ were recorded as displaying the lowest content in terms of total soluble substances. Titratable acidity as a percentage of malic acid had limits in the range of 0.20 and 1.16%, and the average over the entire experience was 0.5%. The genotypes with the highest titratable acidity were ‘Reinette Osnabruck’ and ‘Sir Prize’, while in opposition to them were ‘Red Delicious Redkan’, ‘Sovari’, and ‘T195’. Wide limits of variability were recorded for the carotenoid content of fruits, with the amplitude ranging between 0.35 and 6.60 mg/100 g. ‘Reinette de Champagne’ and ‘Baujade’ were noted for the highest carotenoid content, while ‘Judor’ and ‘Elstar’ were recorded as displaying the lowest content.

Among the genotypes tested, 22 were also analyzed for chlorophyll content in their fruits. Among these 22 cultivars, a large variation in chlorophyll a, chlorophyll b, and total chlorophyll content was identified, highlighted by significant differences (

Table 4. Fruit content in chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (Chl total) in μg/g in 22 apple cultivars.

No *	Cultivar	Chl a (µg/g)	Chl b (µg/g)	Chl Total (µg/g)
1	‘Crețesc Auriu’	83.2 ± 1.2 cd	59.3 ± 3.4 cd	142.4 ± 4.6 c
2	‘Domnesc’	45.0 ± 2.4 d	17.0 ± 0.6 ef	62.0 ± 3.0 ef
3	‘Patul’	92.8 ± 3.2 c	93.9 ± 7.5 a	186.7 ± 10.7 b
4	‘Poinic’	49.5 ± 3.0 d	26.1 ± 0.1 e	69.3 ± 4.9 de
5	‘Sovari’	93.1 ± 9.7 c	66.0 ± 3.8 c	159.1 ± 13.5 c
6	‘Grimes Golden’	95.2 ± 7.9 bc	40.0 ± 1.5 de	135.1 ± 9.3 c
7	‘James Grieve’	44.9 ± 3.2 d	21.2 ± 2.2 ef	66.2 ± 3.3 e
8	‘Kaltherer Böhmer’	49.4 ± 4.0 d	39.6 ± 5.9 de	89.0 ± 9.9 d
9	‘Reinette de Champagne’	105.6 ± 0.1 b	53.1 ± 4.1 d	158.7 ± 4.2 c
10	‘Reinette Harbert’	88.8 ± 1.1 c	56.4 ± 1.8 cd	145.3 ± 2.9 c
11	‘Reinette du Canada’	111.6 ± 5.5 b	39.3 ± 4.3 de	150.8 ± 9.3 c
12	‘Baujade’	144.8 ± 10.2 a	76.6 ± 8.9 b	221.4 ± 18.1 a
13	‘Enterprise’	68.9 ± 7.0 d	30.7 ± 1.3 e	99.6 ± 8.2 d
14	‘Goldrush’	35.1 ± 4.0 de	33.1 ± 1.4 e	68.2 ± 4.9 e
15	‘Granny Smith’	106.6 ± 3.8 b	62.3 ± 4.5 c	169.0 ± 7.6 bc
16	‘Judor’	56.0 ± 1.6 d	20.4 ± 4.0 ef	76.4 ± 5.6 de
17	‘Juliana’	30.3 ± 3.9 e	15.2 ± 3.2 f	45.5 ± 7.1 f
18	‘Jurella’	70.5 ± 8.3 d	40.6 ± 0.4 de	111.1 ± 8.7 d
19	‘Sir Prize’	61.1 ± 2.9 d	46.6 ± 8.6 d	107.7 ± 11.5 d
20	‘T107’	27.1 ± 3.9 e	14.9 ± 4.0 f	42.0 ± 7.9 f
21	‘T194’	88.2 ± 3.2 c	50.8 ± 5.0 d	139.1 ± 5.2 c
22	‘T195’	36.7 ± 4.6 de	12.4 ± 3.5 g	49.1 ± 8.1 f

* 1–5: autochthonous (Romanian) cultivars; 6–11: international ‘classic’ (old) cultivars; 12–19: international modern cultivars; 20–22: new selections. According to Duncan’s test (α < 0.05), there is no significant difference between any two means in a column that are followed by the same letter for each trait.

). The mean values of the chlorophyll parameters were as follows: 72.0 µg/g for chlorophyll a, 41.6 µg/g for chlorophyll b, and 113.3 µg/g for total chlorophyll. The limits of variation for the chlorophyll content of the fruits ranged between the following levels: 27.1–144.8 µg/g for chlorophyll a, 12.4–93.9 µg/g for chlorophyll b, and 42.0–221.4 µg/g for total chlorophyll.

Figure 3 illustrates the data produced by classifying genotypes into three unique groups—traditional Romanian varieties, classic international varieties, and contemporary international varieties—when employing boxplot for data analysis. The most important characteristics of the fruits were chosen from all the traits assessed. However, we excluded a group of new selections due to their insufficient number (only three genotypes), rendering such a group unrepresentative. Statistical analysis did not reveal significant differences (p < 5%) for the examined traits between groups in terms of the provenance and origin of genotype categories. In addition, the differences between groups were not significant for the other analyzed characteristics not depicted in this figure.

However, boxplots provide a suggestive picture of the groups of cultivars in the form of minimum values, lower quartiles, median, upper quartiles, and maximum values of the parameters per group. In addition, inside the boxes, ‘x’ represents the mean of the trait, and for some traits there are also outliers that are revealed by the boxplots. Cultivars from the international old ‘classic’ group had the highest mean for five of the eight traits that were displayed. Cultivar groups, highlighted by the boxplot with outliers, were recorded for the following traits: fruit weight, fruit volume, and titratable acidity. In the case of the last trait, three outliers appeared.

3.2. Results of Multivariate Analyses

Due to the large number of analyzed traits, principal component analysis (PCA) was employed to compare and categorize the examined apple genotypes (Figure 4) into specific characteristic groups, including the morphological traits of the fruits (Figure 4a); the textural attributes of the fruit pulp and skin (Figure 4b); the quantity of analyzed chemical elements in the fruits (Figure 4c); and the chlorophyll content of the fruits (Figure 4d).

In terms of the morphological attributes of the fruits, the first principal component (PC1) of the PCA accounted for the majority of the overall variance at 65.3%, whilst the second principal component (PC2) accounted for 23.6%. Fruit width, volume, and weight were situated in proximity inside the second quadrant of the PCA figure (Figure 4a), but fruit height and shape index were positioned in the first quadrant. Based on the physical qualities of the fruits, the most divergent varieties were ‘Sir Prize’ and ‘Belle de Boskoop’, positioned diagonally in quadrants 1 and 3, while ‘Patul’ was opposed to the pair of ‘Golden Orange’ and Reinette de Canada and was situated in quadrants 4 and 2.

The fruit texture and skin attributes exhibited specific characteristics, with PC1 explaining 70.7% of the total variation and PC2 contributing 20.8%. ‘James Grieve’ and ‘Belle de Boskoop’ were positioned separately from the other types in isolated locations within the upper quadrants (Figure 4b). ‘James Grieve’ was in opposition and situated far from ‘Jurella’, as well as from ‘Reinette de Champagne’, ‘Reinette Osnabruck’, and ‘Golden Delicious’.

The main chemical components examined were distributed rather evenly throughout three of the four quadrants of the PCA (Figure 4c). ‘James Grieve’, ‘Pearmain’, and ‘Juliana’ were located furthest from the intersection of the two primary axes in quadrant one, whereas selection ‘T195’ was situated in quadrant three, and ‘Sir Prize’ and ‘Baujaude’ were found in quadrant four. In quadrant four, positioned somewhat far yet near the horizontal axis, were ‘Granny Smith’, ‘Jurella’, and ‘Reinette de Champagne’. Principal component PC1 accounted for 46.3% of the overall variation, whereas PC2 represented 26.0%.

In the PCA plot of the three elements of chlorophyll content, chlorophyll a and b and total chlorophyll were spread at quite equal intervals in quadrants one and two (Figure 4d). Total chlorophyll was positioned nearly equidistant between the two components a and b. The dimensionality reduction in data from the 22 cultivars used in the PCA for chlorophyll content revealed the varieties most distant from the plot’s center: ‘Patul’ in quadrant one and ‘Baujade’ in quadrant two. Additionally, at a considerable distance from the intersection of the two primary axes were the selections ‘T107’ and ‘T195’, situated to the left of the graph and near the horizontal axis. PC1 accounted for the majority of the overall variation, at 92.9%, whereas PC2 represented just 6.7%.

Multivariate analysis, specifically hierarchical clustering utilizing Ward’s method and the Euclidean similarity index, was conducted using the mean values of the analyzed parameters. This analysis reveals noteworthy relationships among the 34 apple genotypes, as illustrated in the column dendrogram, as well as the proximity or distance of certain analyzed characteristics, represented in the row dendrogram (Figure 5).

The column dendrogram displays the cultivars, organized into two primary clusters, each containing multiple secondary branches. The left cluster comprises two subclusters: one is only represented by the ‘Sir Prize’ variety, and the other by two branches, one with branched subclusters and the other with a pair of varieties, namely, ‘Reinette Osnabruck’ and ‘Reinette du Canada’. In the second subcluster, close relationships appear at the pair level, typically exhibiting a lack of predictability, as detailed below: ‘Crețesc Auriu’ is paired with ‘Reinette Harbert’; ‘Enterprise’ combines with ‘Red Delicious Redkan’; ‘Kaltherer Böhmer’ is seen alongside ‘Granny Smith’; ‘Florina’ is associated with ‘T194’; ‘Sovari’ is linked with ‘Jonathan’; and ‘Poinic’ is connected with Green Golden. The main cluster on the right has two branching subclusters. Within these, there are close pairs between the following cultivars: ‘Wagener’ is with ‘Cox’s Orange Pippin’; ‘Patul’ is with ‘Golden Delicious’; ‘Elstar’ is with ‘Judor’; ‘James Grieve’ is with ‘Pearmain’; ‘Reinette de Champagne’ is with ‘Baujade’.

In the horizontal dendrogram, the characters are grouped into two main sub-clusters, the bottom one comprising the morphological characteristics of the fruits, grouped into two pairs: height with fruit diameter; fruit volume with weight. In the other subcluster, hardness pairs with flesh hardness, total acidity pairs with carotenoids, and fruit ash content pairs with toughness.

The heat map illustrates the physical characteristics that enhance the commercial attractiveness of fruits (size, weight, volume) of the cultivars in the primary cluster on the left. Warm hues predominate for these varieties in terms of fruit appearance. They encompass Romanian old varieties, classic and modern international varieties, and the three selections developed from the breeding process.

On the right, Figure 6 illustrates the strong correlations among all attributes examined through the fruit organoleptic evaluation bulletins, indicating that every element influencing fruit quality, as a commercial aspect or intrinsic characteristic of the pulp, texture, juiciness, taste, and flavor, contributes to the final and comprehensive score of apple quality. The only exceptions that registered insignificant correlations between organoleptic and morphological characteristics were the relationships between aroma and fruit size, as well as between juiciness and fruit shape. Positive and predictable correlations were recorded between the main characteristics of the fruits concerning their dimensions and size. These were also recorded between peel hardness and toughness and flesh hardness, and between flesh hardness and hardness work. Less predictable were the significant correlations between fruit and pulp color with fruit size and volume, and fruit shape and carotenoid content with peel hardness.

Significant negative correlations were also recorded, reflecting inversely proportional relations between some of the analyzed attributes. Thus, fruit height was negatively correlated with toughness, flesh hardness, hardness work, and total soluble solids (TSS). TSS was negatively correlated with peel hardness, hardness, and fruit moisture. Other negative correlations were recorded between fruit ash content and moisture, respectively, and between titratable acidity and carotenoid content.

3.3. Organoleptic Properties of Fruits

The organoleptic evaluations of the fruits, which were conducted by creating assessment sheets of the main characteristics that contribute to the commercial appearance of the fruits as well as the intrinsic peculiarities of the fruit pulp, taste, and aroma, revealed substantial variations between the tested cultivars (

Table 5. Average scores and standard error of the mean (mean ± SEM) for the main attributes influencing fruit quality derived from organoleptic assessments conducted on 34 apple cultivars.

No *	Cultivar	Fruit Size	Fruit Shape	Fruit Color	Pulp Color	Consistency	Juiciness	Taste	Aroma
1	‘Crețesc Auriu’	2.6 ± 0.2	2.6 ± 0.3	4.2 ± 0.2	3.0 ± 0.3	2.6 ± 0.3	3.6 ± 0.3	10.2 ± 0.8	3.0 ± 0.4
2	‘Domnesc’	2.6 ± 0.3	2.8 ± 0.4	3.0 ± 0.4	2.9 ± 0.6	2.6 ± 0.3	3.0 ± 0.4	9.3 ± 0.7	3.1 ± 0.5
3	‘Patul’	1.4 ± 0.1	2.2 ± 0.2	3.4 ± 0.2	2.4 ± 0.3	2.5 ± 0.4	4.0 ± 0.5	11.8 ± 0.9	4.1 ± 0.3
4	‘Poinic’	2.5 ± 0.3	2.3 ± 0.2	2.1 ± 0.1	1.4 ± 0.1	1.6 ± 0.3	2.1 ± 0.2	6.0 ± 0.5	2.5 ± 0.4
5	‘Sovari’	2.3 ± 0.3	2.3 ± 0.3	3.9 ± 0.6	2.8 ± 0.8	2.3 ± 0.3	3.0 ± 0.3	9.0 ± 0.9	2.6 ± 0.3
6	‘Belle de Boskoop’	2.8 ± 0.1	2.8 ± 0.3	4.2 ± 0.7	3.0 ± 0.3	2.6 ± 0.4	3.6 ± 0.5	11.2 ± 0.7	3.6 ± 0.5
7	‘Cox’s Orange Pippin’	1.9 ± 0.2	2.1 ± 0.2	3.0 ± 0.3	2.6 ± 0.4	2.6 ± 0.4	4.4 ± 0.4	13.3 ± 1.0	4.3 ± 0.4
8	‘Golden Delicious’	2.9 ± 0.2	3.0 ± 0.3	3.6 ± 0.7	2.8 ± 0.4	2.9 ± 0.5	4.5 ± 0.8	13.9 ± 0.9	4.6 ± 0.4
9	‘Grimes Golden’	2.1 ± 0.1	2.4 ± 0.3	2.6 ± 0.3	2.7 ± 0.9	2.8 ± 0.4	2.7 ± 0.3	9.8 ± 0.7	3.6 ± 0.5
10	‘James Grieve’	2.3 ± 0.4	2.0 ± 0.3	2.2 ± 0.1	2.3 ± 0.3	2.0 ± 0.3	3.3 ± 0.3	10.3 ± 0.8	3.2 ± 0.5
11	‘Jonathan’	2.8 ± 0.2	2.7 ± 0.2	4.4 ± 0.5	3.0 ± 0.3	2.8 ± 0.3	4.5 ± 0.5	14.0 ± 0.9	4.6 ± 0.6
12	‘Kaltherer Böhmer’	3.0 ± 0.5	3.0 ± 0.2	4.9 ± 0.5	3.0 ± 0.3	2.9 ± 0.5	3.9 ± 0.3	13.6 ± 1.1	4.3 ± 0.4
13	‘Pearmain’	1.5 ± 0.2	2.0 ± 0.4	1.3 ± 0.1	2.1 ± 0.2	2.0 ± 0.3	2.5 ± 0.4	8.0 ± 0.7	3.1 ± 0.5
14	‘Reinette de Champagne’	2.5 ± 0.3	2.1 ± 0.3	2.3 ± 0.3	2.5 ± 0.4	2.8 ± 0.3	4.5 ± 0.6	12.3 ± 0.9	4.3 ± 0.7
15	‘Reinette Harbert’	2.0 ± 0.1	1.1 ± 0.2	2.0 ± 0.4	2.2 ± 0.4	2.1 ± 0.4	2.6 ± 0.3	5.1 ± 0.5	2.0 ± 0.3
16	‘Reinette Osnabruck’	2.3 ± 0.4	2.6 ± 0.4	2.5 ± 0.3	2.8 ± 0.3	2.3 ± 0.3	3.7 ± 0.2	10.0 ± 0.7	3.8 ± 0.6
17	‘Reinette du Canada’	3.0 ± 0.2	2.8 ± 0.2	2.9 ± 0.2	2.1 ± 0.3	1.8 ± 0.3	2.3 ± 0.3	6.1 ± 0.7	2.7 ± 0.5
18	‘Wagener’	2.4 ± 0.3	2.6 ± 0.3	2.9 ± 0.3	2.7 ± 0.3	2.8 ± 0.3	4.0 ± 0.6	11.3 ± 0.8	3.8 ± 0.5
19	‘Baujade’	2.8 ± 0.5	2.9 ± 0.2	3.2 ± 0.4	2.0 ± 0.3	2.0 ± 0.3	3.2 ± 0.3	7.3 ± 0.6	2.3 ± 0.3
20	‘Champion’	2.8 ± 0.4	2.6 ± 0.3	2.1 ± 0.3	2.7 ± 0.3	2.7 ± 0.5	4.0 ± 0.3	11.8 ± 1.1	3.9 ± 0.5
21	‘Elstar’	1.5 ± 0.2	2.1 ± 0.4	3.1 ± 0.4	2.5 ± 0.4	2.4 ± 0.4	3.8 ± 0.5	11.9 ± 0.7	4.0 ± 0.6
22	‘Enterprise’	1.6 ± 0.2	2.0 ± 0.3	3.2 ± 0.5	2.6 ± 0.3	1.8 ± 0.2	3.4 ± 0.3	8.0 ± 0.7	2.6 ± 0.3
23	‘Florina’	2.6 ± 0.3	2.8 ± 0.2	4.5 ± 0.9	2.9 ± 0.5	2.5 ± 0.3	4.1 ± 0.5	13.1 ± 0.9	4.5 ± 0.5
24	‘Golden Orange’	2.9 ± 0.2	2.9 ± 0.5	4.6 ± 0.3	3.0 ± 0.3	3.0 ± 0.5	4.9 ± 0.6	15.0 ± 1.1	5.0 ± 0.6
25	‘Goldrush’	2.7 ± 0.6	2.6 ± 0.4	3.4 ± 0.5	2.9 ± 0.5	2.8 ± 0.5	3.4 ± 0.5	11.8 ± 0.9	3.6 ± 0.6
26	‘Granny Smith’	2.8 ± 0.2	2.8 ± 0.2	4.4 ± 0.5	2.6 ± 0.3	2.3 ± 0.4	3.4 ± 0.6	8.5 ± 0.6	3.0 ± 0.5
27	‘Judor’	1.3 ± 0.2	2.0 ± 0.3	1.7 ± 0.4	2.1 ± 0.2	2.2 ± 0.3	3.0 ± 0.5	8.2 ± 0.7	2.9 ± 0.3
28	‘Juliana’	1.4 ± 0.3	1.9 ± 0.2	2.3 ± 0.2	1.8 ± 0.2	1.3 ± 0.3	1.6 ± 0.2	4.0 ± 0.3	1.5 ± 0.2
29	‘Jurella’	1.3 ± 0.2	2.4 ± 0.4	2.7 ± 0.5	2.2 ± 0.3	2.6 ± 0.4	2.9 ± 0.4	11.1 ± 0.9	3.1 ± 0.5
30	‘Red Delicious Redkan’	2.7 ± 0.4	3.0 ± 0.2	4.2 ± 0.3	2.4 ± 0.2	2.5 ± 0.2	2.6 ± 0.3	11.8 ± 0.5	3.4 ± 0.3
31	‘Sir Prize’	1.6 ± 0,3	2.0 ± 0,3	2.4 ± 0.3	2.2 ± 0.4	1.6 ± 0.4	2.8 ± 0.5	7.0 ± 0.3	3.0 ± 0.5
32	‘T107’	2.3 ± 0.3	2.3 ± 0.4	3.6 ± 0.5	2.9 ± 0.3	2.7 ± 0.3	3.9 ± 0.4	12.4 ± 1.2	4.1 ± 0.6
33	‘T194’	2.8 ± 0.2	2.7 ± 0.2	3.7 ± 0.3	2.6 ± 0.4	2.7 ± 0.2	4.3 ± 0.5	14.1 ± 0.9	4.5 ± 0.6
34	‘T195’	2.4 ± 0.3	2.4 ± 0.3	1.8 ± 0.4	2.6 ± 0.3	1.4 ± 0.3	2.8 ± 0.4	7.0 ± 0.6	1.9 ± 0.3
	Scoring range	1−3	1−3	1−5	1−3	1−3	1−5	1−15	1−5
	Minimum value	1.3	1.1	1.3	1.4	1.3	1.6	4.0	1.5
	Maximum value	3.0	3.0	4.9	3.0	3.0	4.9	15.0	5.0
	Mean value	2.3	2.4	3.1	2.5	2.4	3.4	10.2	3.4

* 1–5: autochthonous (Romanian) cultivars; 6–18: international ’classic’ (old) cultivars; 19–31: international modern cultivars; 32–34: new selections.

).

The highest scores for visually assessed fruit color were recorded for cultivars ‘Kaltherer Böhmer’, ‘Golden Orange’, and ‘Florina’. Cultivars ‘Golden Orange’, ‘Golden Delicious’, and ‘Kaltherer Böhmer’ recorded the highest scores for fruit consistency. The highest scores for optimal fruit juiciness were achieved by ‘Golden Orange’, ‘Golden Delicious’, ‘Jonathan’, and ‘Reinette de Champagne’. In terms of taste quality, ‘Golden Orange’, ‘T194’, ‘Jonathan’, and ‘Golden Delicious’ scored the best grades. ‘Golden Orange’, ‘Golden Delicious’, and ‘Jonathan’ received the highest ratings for flavor quality.

Depending on the commercial aspect of the fruits, the highest scores were recorded by varieties ‘Kaltherer Böhmer’ and ‘Golden Orange’ (

Table 6. Hierarchy of general scores for appearance (commercial aspect), pulp attributes (intrinsic fruit value), and total score (overall fruit quality), derived from organoleptic assessments * conducted on 34 apple cultivars.

No.	Cultivar—Appearance Score (Mean ± SEM) and Significance			Cultivar—Pulp Score (Mean ± SEM) and Significance			Cultivar—Total Score (Mean ± SEM) and Significance
1	‘K. Böhmer’	3.63 ± 0.30	a	‘Golden Orange’	6.18 ± 0.38	a	‘Golden Orange’	5.16 ± 0.30	a
2	‘Golden Orange’	3.47 ± 0.29	ab	‘Jonathan’	5.78 ± 0.37	b	‘Jonathan’	4.85 ± 0.31	b
3	‘Granny Smith’	3.33 ± 0.22	b	‘Golden D.’	5.74 ± 0.35	b	‘K. Böhmer’	4.83 ± 0.30	b
4	‘Jonathan’	3.30 ± 0.20	b	‘T194’	5.64 ± 0.32	b	‘Golden D.’	4.78 ± 0.25	b
5	‘Florina’	3.30 ± 0.22	b	‘K. Böhmer’	5.54 ± 0.33	b	‘T194’	4.68 ± 0.27	b
6	‘R.D. Redkan’	3.30 ± 0.21	b	‘Cox’s Orange P.’	5.44 ± 0.31	b	‘Florina’	4.63 ± 0.29	b
7	‘Boskoop’	3.27 ± 0.20	b	‘Florina’	5.42 ± 0.30	b	‘Cox’s Orange P.’	4.28 ± 0.28	c
8	‘Golden D.’	3.17 ± 0.19	bc	‘R. Champagne’	5.28 ± 0.32	bc	‘T107’	4.28 ± 0.24	c
9	‘Crețesc A.’	3.13 ± 0.18	bc	‘T107’	5.20 ± 0.31	bc	‘Boskoop’	4.23 ± 0.27	c
10	‘T194’	3.07 ± 0.19	c	‘Champion’	5.02 ± 0.30	c	‘R. Champagne’	4.16 ± 0.28	c
11	‘Baujade’	2.97 ± 0.15	cd	‘Patul’	4.96 ± 0.29	c	‘Goldrush’	4.15 ± 0.24	c
12	‘Goldrush’	2.90 ± 0.18	cd	‘Wagener’	4.92 ± 0.28	c	‘Champion’	4.08 ± 0.29	c
13	‘R. Canada’	2.90 ± 0.14	cd	‘Elstar’	4.92 ± 0.29	c	‘R.D. Redkan’	4.08 ± 0.22	c
14	‘Domnesc’	2.80 ± 0.16	d	‘Goldrush’	4.90 ± 0.27	c	‘Wagener’	4.06 ± 0.21	c
15	‘Sovari’	2.79 ± 0.15	d	‘Boskoop’	4.80 ± 0.25	c	‘Patul’	3.98 ± 0.20	c
16	‘T107’	2.73 ± 0.18	d	‘R.D. Redkan’	4.54 ± 0.29	cd	‘Crețesc A.’	3.98 ± 0.23	c
17	‘Wagener’	2.63 ± 0.17	de	‘R. Osnabruck’	4.52 ± 0.28	cd	‘Elstar’	3.91 ± 0.24	cd
18	‘Champion’	2.50 ± 0.15	e	‘Crețesc A.’	4.48 ± 0.30	cd	‘R. Osnabruck’	3.75 ± 0.25	d
19	‘R. Osnabruck’	2.47 ± 0.14	e	‘Jurella’	4.38 ± 0.25	d	‘Granny Smith’	3.73 ± 0.21	d
20	‘Grimes G.’	2.37 ± 0.17	e	‘Grimes G.’	4.32 ± 0.24	d	‘Domnesc’	3.66 ± 0.22	d
21	‘Patul’	2.33 ± 0.16	e	‘James Grieve’	4.22 ± 0.27	d	‘Grimes G.’	3.59 ± 0.23	d
22	‘Cox’s Orange P.’	2.33 ± 0.15	e	‘Domnesc’	4.18 ± 0.26	d	‘Jurella’	3.54 ± 0.21	d
23	‘Poinic’	2.30 ± 0.14	e	‘Granny Smith’	3.96 ± 0.25	de	‘Sovari’	3.50 ± 0.20	d
24	‘R. Champagne’	2.30 ± 0.15	e	‘Sovari’	3.93 ± 0.28	de	‘James Grieve’	3.45 ± 0.21	d
25	‘Enterprise’	2.27 ± 0.16	e	‘Enterprise’	3.68 ± 0.27	e	‘Baujade’	3.21 ± 0.23	de
26	‘Elstar’	2.23 ± 0.15	e	‘Judor’	3.68 ± 0.29	e	‘Enterprise’	3.15 ± 0.20	de
27	‘T195’	2.20 ± 0.14	ef	‘Pearmain’	3.54 ± 0.30	e	‘R. Canada’	2.96 ± 0.18	e
28	‘James Grieve’	2.17 ± 0.15	ef	‘Baujade’	3.36 ± 0.16	e	‘Judor’	2.93 ± 0.19	e
29	‘Jurella’	2.13 ± 0.13	ef	‘Sir Prize’	3.32 ± 0.19	e	‘Sir Prize’	2.83 ± 0.18	e
30	‘Sir Prize’	2.00 ± 0.12	f	‘T195’	3.14 ± 0.17	f	‘Pearmain’	2.81 ± 0.17	e
31	‘Juliana’	1.87 ± 0.11	fg	‘R. Canada’	3.00 ± 0.15	f	‘T195’	2.79 ± 0.14	e
32	‘R. Harbert’	1.70 ± 0.09	g	‘R. Harbert’	2.80 ± 0.18	fg	‘Poinic’	2.56 ± 0.12	ef
33	‘Judor’	1.67 ± 0.08	g	‘Poinic’	2.72 ± 0.11	g	‘R. Harbert’	2.39 ± 0.11	f
34	‘Pearmain’	1.60 ± 0.09	g	‘Juliana’	2.04 ± 0.12	h	‘Juliana’	1.98 ± 0.10	g
	Minimum value	1.60			2.04			1.98
	Maximum value	3.63			6.18			5.16
	Mean value	2.62			4.40			3.73

* Appearance is the weighted average of the following characteristics: fruit size, fruit shape, and fruit color. Pulp is the weighted average of the following characteristics: pulp color, consistency, juiciness, taste, and aroma. Total is the weighted average of the appearance and pulp traits, respectively, reflecting the overall quality of the fruits assessed organoleptically by the tasters. According to Duncan’s test (α < 0.05), there is no significant difference between any two values in a column when followed by the same letter for each trait.

). Scores reflecting the favorable particularities that contribute to the commercial aspect were also obtained by the varieties ‘Granny Smith’, ‘Jonathan’, ‘Florina’, ‘Red Delicious Redkan’, ‘Belle de Boskoop’, ‘Golden Delicious’, and ‘Crețesc Auriu’. ‘Golden Orange’ distinguished itself through its inherent fruit quality attributes in an ensemble represented by pulp color, consistency, juiciness, taste, and aroma. Despite the pulp qualities of ‘Golden Orange’ significantly surpassing all evaluated cultivars, it was closely followed by ‘Jonathan’, ‘Golden Delicious’, ‘T194’, ‘Kaltherer Böhmer’, ‘Cox’s Orange Pippin’, and ‘Florina’. Ultimately, based on the organoleptic attributes of the fruits, the panel of tasters determined the subsequent ranking of the most appreciated cultivars out of the 34 analyzed: ‘Golden Orange’, ‘Jonathan’, ‘Kaltherer Böhmer’, ‘Golden Delicious’, ‘T194’, and ‘Florina’.

The comparative analysis among the three primary groups of cultivars reveals that, in six out of the eight organoleptic characteristics assessed, superior results were achieved by the second group, comprising classic international cultivars developed prior to the 20th century (Figure 7). The color of the fruits was the only organoleptic feature valued by tasters, with the highest average score for the group represented by traditional (old) Romanian cultivars.

Analysis by group reveals that for the commercial aspect, the best organoleptic score as a sum of the grades for the specific traits was noted in the old Romanian varieties and for internal traits of fruit in the classic international varieties (Figure 8). The comprehensive evaluation of fruit sensorial quality reveals that classic international cultivars were predominant for the total score (for overall fruit quality), followed by new or modern international ones, and subsequently by traditional Romanian old cultivars.

4. Discussion

The examination of the germplasm resource, comprising 34 apple cultivars, revealed substantial variations among the studied genotypes in terms of important organoleptic, biochemical, and morphological traits of the fruit. The study indicated considerable variation among cultivars for most fruit attributes, which are of significant interest for apple breeding, apple cultivation, and fruit uses. For each characteristic analyzed, varieties that stood out for their superior values or attributes were highlighted so that they could be used for different purposes. It is known that, depending on their characteristics, different varieties may be more suitable for certain destinations or fruit uses, namely, for fresh consumption, home or industrial processing, and use in cakes, tarts, pies, jams, compotes, purees, juices, jellies, vinegar, cider, alcohol, etc. [23,41,57]. Therefore, varieties highlighted for different attributes may be primarily applied for uses in which they seem more suitable.

The association of the main morphological characteristics of the fruits (dimensions, shape, weight, volume) with those appreciated sensorially (size, shape, color) provided a general picture of the cultivars with an attractive commercial appearance. It is interesting to note that, among the respective cultivars, there were old varieties, including the international ones considered ’classic’ (for example ‘Jonathan’, ‘Kaltherer Böhmer’, and ‘Golden Delicious’), but also some old Romanian varieties. ‘Crețesc Auriu’, a clonal selection from a very old Romanian native variety, ‘Crețesc’, is a suggestive example, dating from the period of “empirical” apple breeding. The very good appreciation enjoyed by some varieties from the classic international assortment in Romania, such as ‘Jonathan’, but also others such as ‘Kaltherer Böhmer’ in some areas of Transylvania, probably also reflects their good adaptation to local environmental conditions. In addition, the commercial quality given by their generally attractive appearance, namely, the intense and bright color that the fruits acquire, especially in long and beautiful autumns with warm and sunny days and cooler nights, is complemented by the good gustatory quality and flavor of the fruits. Certainly, the intrinsic peculiarities of the fruits and their wide variation depend on both the genotype and the environmental conditions and the interactions between the genotype and the environment [58,59,60]. Both the characteristics of the fruit skin and the texture of the fruit pulp, as well as the biochemical composition of the fruits, highlight significant differences between the analyzed cultivars. The investigation of apple peel and texture revealed significant variation among cultivars in peel hardness, flesh firmness, and fruit toughness, traits that may influence storability and consumer preferences [61,62].

The wide amplitude for total soluble solids (10.6–20.7%), as well as the water and ash content of the fruits, or titratable acidity, especially the content in total carotenoids (0.35–6.60 mg/100 g), was both due to the differences related to the cultivars (as genotypes) and a direct consequence of the ecological and technological conditions in which the fruits were obtained, which can influence the chemical content [63,64,65]. This is probably how the differences between the numerous studies conducted on apples for similar biochemical characteristics and the rather wide limits between which they can vary can be explained [13,66]. Other influences can be added due to the maturity of the fruit harvest, the storage period of the fruit and the storage conditions until the analyses are performed, the procedures by which the analyses were performed, the methods used, etc. [67,68,69]. However, the importance of apples for human health and their nutritional values is expressed not only through the consumption of fresh fruit but also through various other ways of use and processing [19,70,71,72].

The classification of the cultivars analyzed in the present study into three main groups provided interesting information and perhaps even a surprise compared to a previously unformulated hypothesis, even if it is one which is considered self-evident. Thus, we expected to identify significant genetic progress between the three distinct groups of cultivars that represent three different eras from a historical point of view and the evolution of apple breeding and cultivation. However, statistically, no significant differences were recorded between the three groups regarding the main elements that contribute to the overall quality of apples. However, it can be considered a surprise that it was not the group of modern varieties that recorded the best results for the morphological, biochemical, and sensory characteristics of the fruits, but the group of classic international varieties, represented by varieties originating mostly from the 18th and 19th centuries. After all, the explanations could be due to the good adaptation of these cultivars to the pedoclimatic conditions in Romania and, of course, to the fact that the analyzed cultivars represented only small samples of the extremely large number of apple varieties existing internationally [73,74].

Another objective pursued in the present study was to identify possible parental forms for new breeding works through hybridization. Artificial hybridization remains one of the main methods of causing the variability necessary for the selection of new superior genotypes and the creation of new cultivars [75,76]. The efficiency of the selection of new varieties depends directly on the value of the parental forms used in directed crosses and on the pertinent selection of maternal or paternal parents [77]. Assortment studies, such as the one we conducted to identify possible parents with superior quality fruits and suitability for a specific destination, are crucial for the success of apple breeding [78].

Our study confirms the exceptional qualitative value of the fruits of numerous cultivars from the classic international assortment, which continue to enjoy very good appreciation and are extremely well rated in terms of quality in the world or in Romania. The ‘Jonathan’ variety is widespread and appreciated among Romanian growers and consumers. In addition, it has been used as a parental form in numerous artificial hybridizations, giving rise to new native cultivars. Many Romanian varieties from the so-called ’modern’ era of apple breeding, including some obtained in Cluj-Napoca, such as ‘Aromat de vară’, ‘Ardelean’, ‘Feleac’, ‘Ancuța’, and ‘Roșu de Cluj’, had ‘Jonathan’ as a common parent [75]. ‘Golden Delicious’ is also very well appreciated, which, unlike ‘Jonathan’, remains a basic variety in the current cultivated assortment in Romania. ‘Golden Delicious’, like ‘Jonathan’, has also participated in complex hybridizations, even several times as a common parental form of the same new cultivar, such as the ‘Precoce de Ardeal’, with a complex origin (Figure 9), obtained at SCH Cluj-Napoca [79]. Although ‘Precoce de Ardeal’ lacks the Vf resistance gene for apple scab (overcome later), it shares a partially shared lineage with varieties resulting from Crandall’s early 20th-century cross between Malus floribunda 821 and ‘Rome Beauty’ [80]. Such selection schemes demonstrate the complex processes of apple breeding and the numerous generations of hybridization or backcrossing and successive selection needed to create a new variety. At the same time, it also reflects the narrowing of the genetic endowment of varieties through the excessive and repeated use of the best-rated varieties worldwide as parents. In addition, the inbreeding that inevitably occurred during the selection processes and a strong intensity of selection for generally common breeding objectives (yield, fruit quality, resistance to biotic and abiotic stressors) impacted and contributed to the narrowing of the gene pool of current cultivars and the increase in genetic vulnerability [81,82,83].

Many of the native Romanian varieties have lost competition with the varieties from the international assortment. As such, some have been lost, while some have a very limited share of the current distribution or are maintained as sources of germplasm. Other varieties that represented childhood apples for many generations in Northwestern Transylvania have proven to be poor parents when used in apple breeding work. Apples of the ‘Poinic’ variety, once widespread in Transylvania but almost extinct today, were found in the schoolbags of many children in past decades. It was famous for its spherically flattened green fruits, with a dense, hard, compact pulp, meaning children would beat them to soften them. The resistant skin did not allow the fruit to break, but inside, the texture of the pulp broke, and the fruit was filled with juice with an incredible taste and flavor. Unfortunately, our prior research has demonstrated that this variety does not possess the necessary traits to be considered a valuable parent in breeding programs, transmitting to its descendants the great vigor and branching growth of the trees, susceptibility to diseases, especially to apple scab, and other less desirable characteristics, including poor fruit quality. Similar to ‘Poinic’, numerous ancient varieties are underutilized due to the subpar quality of their fruits, which frequently fail to satisfy the increasing standards of consumers and processors. Additionally, these varieties exhibit other inferior biological characteristics, such as vulnerability to pathogens and pests, inadequate yield, alternate bearing, and inappropriate tree habits for intensive orchards. Nonetheless, they constitute a vital and dynamic gene repository. However, due to the appreciation of the fruit and the nostalgia of some consumers, ‘Poinic’ (as well as other ancient cultivars) is currently propagated in some nurseries in Transylvania, but this is generally based on relatively small orders directed to private gardens and uses franc rootstock. Nevertheless, the qualitative attributes of the ‘Poinic’ variety, along with other traditional Romanian and classic international apple varieties, highlight their suitability for fresh consumption, home processing, and cooking. Meanwhile, modern varieties, with their refined quality, meet the requirements of the fruit market, while those richest in beneficial compounds are also ideal for industrial processing [84].

Multivariate analyses provide extremely useful information for apple breeding and the selection of new parental forms, useful in causing the variability necessary for the creation of new varieties. In addition, multivariate data analysis approaches can successfully evaluate the sensory qualities and chemical profiles of apple cultivars [85,86,87]. Correlations identified between characters of interest can provide useful information for apple breeding and cultivation. In apple breeding, phenotypic correlations, especially if complemented by genotypic correlations, can be used as selection indices. Thus, an indirect selection can be applied by which selection for a character can be carried out in tandem with another character of interest with which the first is closely correlated. A similar procedure can be used for negatively correlated characters, when selection can be made against a character with which the first is in an inversely proportional relationship [88,89,90]. PCA and hierarchical cluster analyses revealed some unexpected associations for fruit quality between varieties with different historical and geographical origins, all the more surprising as the varieties appeared to be very different in terms of both commercial appearance and sensory value evaluation or recognition (‘Sovari’ with ‘Jonathan’; ‘Poinic’ with Green Golden; ‘Patul’ with ‘Golden Delicious’). The dimensionality reduction in the data in the dendrogram, which encompass all analyzed characteristics, including sensory attributes and the overall organoleptic quality assessment of the fruits (Figure A1), reveals a limited number of cultivars that are closely related by origin. Among the traditional Romanian varieties, ‘Domnesc’ and ‘Crețesc Auriu’ exhibit a close relationship within a paired cluster. ‘Cox’s Orange Pippin’ is paired with ‘Wagener’, while ‘James Grieve’ is paired with ‘Pearmain’, among the classic international varieties. Among the modern genotypes, ‘Florina’ and ‘T194’, as well as ‘Elstar’ and ‘Judor’, constitute pairs. Instead, some close links appear between cultivars from different historical periods: ‘Jonathan’ (which seems to date back to 1826) forms a pair with ‘Golden Orange’ (released in 1996, based on the famous ‘Golden Delicious’), and ‘Kaltherer Böhmer’ (probably originating in Bolzano, northern Italy, before 1810) forms a pair with ‘Goldrush’ (New Jersey, USA, introduced to the market in 1994). The dendrogram created for all examined traits delineates the classification into significantly overlapping subclusters of the morphological, biochemical, and sensory attributes of the fruits (Figure A2), underscoring the significance of pulp attributes, taste, aroma, and juiciness. The commercial appearance is significantly associated with the fruit’s color in a distinct subcluster. The dendrogram’s separation for color and appearance versus overall quality yields crucial insights for the apple quality assessment, but also for apple breeding: regardless of the esthetic appeal of a hybrid’s fruits during the selection process, it cannot attain a varietal status unless the fruits possess exceptional organoleptic qualities, particularly a superior taste.

The closeness of some cultivars belonging to different areas of origin and historic periods, revealed by multivariate analyses based on a very large number of elements contributing to the overall quality of the fruits, may contradict the variability highlighted previously. Or, perhaps, the respective variability is only apparent at the level of amplitudes between genotypes, since the closeness of the cultivars may actually reflect the narrowing of the genetic pool of the cultivated types and the common ancestral origin of many apple cultivars, even if they come from different historical eras and geographical areas of the temperate climate [73]. This genetic narrowing is probably also a consequence of the assiduous selection practiced throughout historical eras of apples for the size of the fruits, their better gustatory quality, their biochemical content in useful substances, and their superior nutritional value, all of which are also associated with resistance or tolerance to abiotic and biotic stress factors of the trees. Numerous studies highlight genetic erosion or genetic vulnerability due to the narrowing of the apple gene pool and the fact that although there are an impressive number of apple varieties, their common origin constitutes a risk factor in the future [83,91,92]. The numerous threats to cultivated species are all the more acute in apple due to intense selection for fruit quality traits including fruit size, for the allogamy and heterozygosity of the apple, and for vegetative propagation by grafting [2,51,93,94].

Modern orchards, characterized by superintensive monoculture systems with insufficient genetic diversity and a restricted array of types, are vulnerable to numerous climatic risks, pests, and diseases. Utilizing wild species in hybridization can enhance genetic diversity and resilience to biotic and abiotic stressors. The methodology was implemented at SCH Cluj, utilizing various Malus species [95,96]. Moreover, phenotypic selection may be integrated with molecular markers in breeding programs [37,77,97,98]. The drawback of utilizing wild species is the significant reduction in the size and quality of the fruit in their progeny. Consequently, the selection process is prolonged in subsequent generations to restore the size and taste quality of the fruits.

This study highlighted the quality of the fruits of many varieties with a rich history and spread nationally or worldwide. Due to the longevity of the trees and vegetative propagation by grafting, many such old apple varieties remain in the assortment and are still well appreciated [99,100]. At the same time, traditional varieties remain a vital gene pool for new apple breeding efforts [101,102,103]. Future research should integrate molecular and genetic approaches to enhance selection processes and ensure adaptability to changing climatic conditions and consumer preferences [104,105]. In addition, to address the limitations of this study, future research should explore several key areas, including yield performance, cultivation costs, and the impact of ecological and cultural factors on fruit quality. Additionally, investigations into market demands, pricing trends, consumer preferences for specific varieties, and emerging directions in the fruit industry are essential. Understanding these aspects will provide valuable insights into current and future trends, helping to guide the development of strategies that align with market dynamics and consumer expectations.

5. Conclusions

This study provides a detailed analysis of 34 apple cultivars, including ancient Romanian varieties, internationally recognized classic and modern cultivars, and new selections. The findings highlight the significant morphological, biochemical, and organoleptic variability among these cultivars, emphasizing the importance of genetic diversity in apple breeding programs. From a morphological perspective, substantial differences were observed in fruit size, shape, and weight. While international classic cultivars exhibited the highest average values for these traits, Romanian autochthonous varieties displayed distinctive features. However, the lack of statistically significant differences among the first three major groups suggests that fundamental traits are preserved over time. The biochemical analysis revealed significant differences in moisture content, total soluble solids, titratable acidity, carotenoid levels, and mineral composition. Certain old Romanian and international cultivars demonstrated highly valuable biochemical profiles, making them suitable for both fresh consumption and processing. For instance, varieties like ‘Reinette de Champagne’ and ‘Baujade’ showed high carotenoid content, enhancing their potential as functional foods with superior nutritional benefits. Additionally, variations in acidity and soluble solids content influence the suitability of different cultivars for specific market demands and consumer preferences. Texture analysis showed notable variability in peel hardness, flesh firmness, and overall toughness, impacting storage and transport resilience. Moreover, the organoleptic evaluation highlighted that cultivars such as ‘Golden Orange,’ ‘Jonathan,’ ‘Kaltherer Böhmer,’ and ‘Golden Delicious’ stood out in terms of flavor, texture, and consumer appeal. In conclusion, this study underscores the necessity of preserving and utilizing both traditional and modern apple cultivars to maintain a diverse and resilient apple industry. The findings provide essential data for breeding programs, orchard management, and market strategies, supporting fruit quality optimization while ensuring the conservation of valuable genetic resources.