Search Results (68)

Background/Objective: Maize (Zea mays L.) is a globally important cereal crop widely cultivated for food, feed, fodder, biofuel production, and various industrial applications. Maize landraces represent a valuable source of genetic diversity that supports adaptationand resilience across diverse agroecological environments. However, evidence on phenotypic diversity based on agro-morphological traits in these landraces remains fragmented across regions and varying analytical approaches. This review synthesized global evidence on phenotypic variation, heritability patterns, experimental designs, statistical methods, and the extent of integration between phenotypic and molecular data. Methods: A systematic literature search was conducted in GoogleScholar, ScienceDirect, PubMed and AGRIS for studies published between 2000 and 2025 evaluating phenotypic diversity in maize landraces. The review followed PRISMA 2020 guidelines, and f50 studies from 30 countries met the eligibility criteria. Results: Substantial and structured phenotypic diversity was consistently reported across studies, with flowering time, plant architecture, and ear and kernel traits emerging as major contributors to landrace differentiation. Traits with moderate to high heritability were mainly morphological and phenological, suggesting relative genetic control and potential suitability for phenotypic selection. In contrast, grain yield showed greater environmental sensitivity and variable heritability, reflecting complex inheritance and genotype × environment interactions. Although molecular markers were incorporated in a some studies, integrative analyses linking phenotypic and genetic data remained limited. Conclusions: Phenotypic evaluation remains a reliable approach for characterizing maize landrace diversity. However, standardized methodologies, greater integration with molecular data and cross-environment validation are needed to strengthen inference and utilization in breeding and conservation. The review also provides recommendations for improving agro-morphological assessment in maize landraces. Full article

Drought is regarded as the most significant environmental factor affecting the productivity of maize (Zea mays L.) worldwide. The integration of maize landraces, conserved in germplasm bank collections, into elite breeding programs could increase the resilience of modern hybrids to drought and mitigate the genetic erosion identified within the genetic base of cultivated maize. In this study, seeds of fifteen Croatian maize landraces were exposed to four levels of drought stress induced by polyethylene glycol (PEG) to evaluate the effect of drought on their seed germination and seedling root parameters. Analysis of variance revealed significant differences among landraces (G) and applied drought stress treatments (PEG) for all traits, as well as a significant PEG × G interaction for all traits except germination potential. The application of the highest drought stress level, caused by a 20% PEG water solution, reduced germination percentage by 51%, germination potential by 99%, root length by 87%, root diameter by 26%, root area by 91% and root volume by 93% compared to the control. Three landraces, MAK7, MAK11 and MAK15, showing high germination potential, long roots and large root area and volume under drought conditions, were identified as pre-breeding candidates for possible reintroduction into modern breeding programs aimed at increasing drought tolerance. The applied method of PEG-induced drought effectively identified drought-tolerant landraces and can be used for rapid screening of drought tolerance in large numbers of genebank accessions conserved in genebanks. Full article

Pod corn (Zea mays var. tunicata) bears leafy glumes that enclose kernels, resembling a partial reversion to wild-forms, yet remains poorly characterized in situ in Mexico. We evaluated Mexican accessions at two contrasting locations to quantify morphological/phenological diversity and to assess functional traits via proximate kernel composition. Standard descriptors captured variation in plant architecture, tassel/ear traits (including glume length), and reproductive timing. Accessions showed strong plasticity and significant accession × environment effects on ear morphology and maturation. Grain yield ranged from 6.32 to 10.78 t ha⁻¹, with peak values comparable to commercial hybrids and above-typical yields reported for native Mexican races (2.7–6.6 t ha⁻¹). Proximate analysis showed that milling with the tunic increased moisture/ash (up to 3.07% vs. 1.80% in dehulled grain), tended to lower fat and protein, and yielded lower crude fiber than dehulled samples (0.78–0.96% vs. 1.59–1.77%); protein varied widely (1.05–6.64%). Thus, the tunic modulates elemental composition, informing processing choices (with vs. without tunic). Our results document a spectrum of morphotypes and highlight developmental diversity and field adaptability. The observed accession × environment responses provide a practical baseline for comparisons with native and improved varieties, and help guide product development strategies. Collectively, these data underscore the high productive potential of pod corn (up to 10.78 t ha⁻¹ under optimal management) and show that including the tunic substantially alters proximate composition, establishing a quantitative foundation for genetic improvement and food applications. Overall, pod corn’s distinctive ear morphology and context-dependent composition reinforce its value for conservation, developmental genetics, and low-input systems. Full article

Aflatoxins (AFs) and fumonisins (FUMs) are among the most prevalent and toxic mycotoxins affecting maize production globally. In Mexico, their co-occurrence poses a significant public health concern, as maize is not only a dietary staple but also predominantly grown and consumed at the household level. This review examines the multifactorial nature of AFs and FUMs contamination in Mexican maize systems, considering the roles of maize germplasm, agricultural practices, environmental conditions, and soil microbiota. Maize landraces, well-adapted to diverse agroecological zones, exhibit potential resistance to AFs contamination and should be prioritized in breeding programs. Sustainable agricultural practices and biocontrol strategies, including the use of atoxigenic Aspergillus flavus strains, are presented as promising interventions. Environmental factors and soil characteristics further influence fungal proliferation and mycotoxin biosynthesis. Advances in microbiome engineering, biological breeding approaches, and predictive modeling offer novel opportunities for prevention and control. The synergistic toxicity of AFs and FUMs significantly increases health risks, particularly for liver cancer, highlighting the urgency of integrated mitigation strategies. While Mexico has regulatory limits for AFs, the lack of legal thresholds for FUMs remains a critical gap in food safety legislation. This comprehensive review underscores the need for biomarker-based exposure assessments and coordinated national policies, alongside multidisciplinary strategies to reduce mycotoxin exposure and enhance food safety in maize systems. Full article

While irrigation is generally required for most summer crops in the Mediterranean region, increasingly scarce water supplies are leading to a demand for more efficient irrigation infrastructure. Here, we assess how three irrigation volumes—100 mm/week (simulating excess water), 55 mm twice per week (moderate supply), and a variable amount adjusted on a weekly basis according to crop water demand (AMP) applied once or twice weekly via drip irrigation—impacted the growth, yield, and ear traits of a local maize variety under low-input farming in central Portugal. We found that irrigation management significantly influenced grain yield and irrigation water use efficiency (IWUE), with the 55 mm treatment applied twice weekly achieving the highest yield (3504 kg ha⁻¹) and IWUE (7.2 kg ha⁻¹ mm⁻¹). The highest irrigation treatment (100 mm/weekly) impaired yield (996 kg ha⁻¹ and 1973 kg ha⁻¹, when water was applied in one or two events), likely due to nutrient leaching, and resulted in the lowest IWRU (1.2 kg ha⁻¹ mm⁻¹ and 2.5 kg ha⁻¹ mm⁻¹, respectively). Biweekly applications tended to increase crop height. Irrigation rate and frequency significantly affected kernel number and size, but not total ear weight or cob-to-ear weight ratio. These findings highlight the importance of irrigation frequency based on crop water demand over blanket approaches based on volume alone. Full article

Purple totomoxtle (maize husk) in native maize represents a phenotypic trait of cultural and agronomic significance within traditional Mesoamerican agroecosystems. This study evaluated the phenotypic expression of anthocyanins in vegetative and reproductive tissues of ten native maize genotypes, including inter-parental crosses derived from both pigmented and non-pigmented lines. Field trials were conducted under rainfed conditions in Chiapas, Mexico. Visual and quantitative assessments included pigmentation intensity, chlorophyll and carotenoid content, ear traits and appearance, grain health, and yield performance. Genotypes exhibiting the purple phenotype showed consistent pigment accumulation in stems, nodes, leaf sheaths, tassels, and bracts (totomoxtle), with statistically significant differences compared to non-pigmented controls. Anthocyanin content in totomoxtle increased by 30% during late developmental stages, whereas chlorophyll and carotenoid levels peaked during early vegetative growth. Pigmented materials displayed healthier grain, enhanced ear appearance, and higher yields, with the JCTM × LLMJ cross reaching 6.60 t ha⁻¹. These findings highlight the functional value of purple totomoxtle and its potential in agroecological programs aimed at resilience, genetic conservation, and integral resource utilization, providing useful criteria such as stable pigment expression and superior yield to guide sustainable reproduction strategies. Full article

Meeting the rising demand for staple grains now requires cultivars that combine high yield, enhanced nutritional value, and strong chemical resilience. Blue-kernel landraces from central Mexico are rich in anthocyanins yet remain highly susceptible to post-emergence herbicides, whereas modern hybrids detoxify these compounds through cytochrome P450 (CYP450) enzymes. We crossed the anthocyanin-rich variety Polimaize with a CYP450-tolerant hybrid and evaluated the two parents and their F₁ segregants (designated “White” and “Yellow”) under greenhouse applications of mesotrione (75 g a.i. ha⁻¹), nicosulfuron (30 g a.i. ha⁻¹), and their mixture. Across 160 plants, the hybrid retained 95% of control dry matter and showed ≤7% foliar injury under all treatments, whereas Polimaize lost 28% biomass and exhibited 36% injury after nicosulfuron. The Yellow class matched hybrid performance while maintaining a blue pericarp and a β-carotene-rich endosperm, demonstrating that nutritional and agronomic traits can be stacked. The White class displayed heterosis-driven compensatory growth, exceeding its untreated biomass by 60% with nicosulfuron and by 82% with the mixture despite transient bleaching. Chlorophyll and carotenoid fluorescence revealed rapid, zeaxanthin-linked photoprotection in all tolerant genotypes, consistent with accelerated CYP450-mediated detoxification. These findings show that broad-spectrum herbicide tolerance can be introgressed into pigment-rich germplasm through conventional breeding, providing a non-transgenic path to herbicide-ready, anthocyanin-rich maize. The strategy preserves local biodiversity while delivering cultivars suited to intensive, weed-competitive agriculture and offers a template for integrating metabolic resilience into other native crops. Full article

The launch of a successful quality-oriented breeding program requires both mining the residual diversity in grain quality parameters contained in the elite, high-yielding breeding material with good agronomic performance and introgression of new germplasm, such as local landraces, with a high level of targeted quality parameters per se. This study analyzed the combining abilities of 31 maize landraces and two divergent inbred lines–testers (ZPL217 and ZPL-255/75-5) regarding the yield and protein, starch, and lipid content, assessed by Near Infrared Reflectance (NIR) spectroscopy as a fast, non-destructive, and cost-effective method. The general combining ability (GCA) defines the average behavior of genotype in hybrid combination, resulting from additive gene action, so positive GCA values of landraces AN13 and AN197 for protein, AN632 for lipids, and AN594 for starch content indicate that they can be valuable sources of the mentioned properties in quality-oriented maize breeding programs. The obtained correlation between starch content and protein and yield (−0.948 **; 0.587 **) pointed out that an increase in the protein content during breeding will be accompanied by a decrease in the starch content and yield. The specific combining ability (SCA) of the testers used, suggests their possible application in establishing and improving quality breeding programs’ initial material. Full article

In Mesoamerica, maize is one of the most important food crops, with México being the center of its origin, domestication, and diversity. The state of Chiapas in southern Mexico is one of the areas with the highest maize landrace diversity. However, information on its genetic diversity, conservation status, and the potential use of maize landraces throughout the entire Chiapas region is lacking. One region where local farmers use and preserve a wide diversity of maize landraces is the Zoque region. Until now, however, the genetic diversity of these maize landraces has not been studied. The aim of this study was to analyze the diversity and genetic structure of maize cultivated in the Zoque region, from Chiapas, Mexico, by using 17 landraces and 48 ISSR loci. The analysis revealed two genetic groups based on geographical origin. The genetic diversity level was moderate (Hbay = 0.29 and I = 0.36) and distributed mainly within landraces (70%). The maize landrace blanco belongs to the Tuxpeño race and Bacalito blanco belongs to the Olotillo race from the Miguel Hidalgo municipality have greater diversity values (Hbay = 0.36, I = 0.45 and Hbay = 0.35, I = 0.45, respectively). The results indicated that the maize landraces cultivated in the Zoque region, Chiapas, Mexico, constitute a valuable genetic resource that can be used for genetic improvement and in conservation programs. Full article

The root system plays an important role in the efficient absorption of nitrogen (N), but there is limited understanding of the growth characteristics of maize roots of different genotypes and their dynamic response to N supply. In this study, landraces in the 1950s and modern hybrids, modern hybrids and their parents, inbred lines with different N efficiency and standard inbred line B73 were used, combined with the dynamic culture method, to observe the dynamic changes in root growth under long-term N stress conditions. The results showed that there were genotypic differences in the response of maize roots to low N. Low N enhances root growth earlier than the increases in shoot-to-root dry matter allocation. With the extension of low N stress, the root biomass of each genotype basically increased significantly from 3 to 6 days and then was gradually reversed by high N on the 12th day. As for shoot biomass, 11 genotypes began to decrease significantly from 6 to 9 days after low-N stress. The total axial root length, primary root length, seminal root length, and the first and second whorl crown root length of seven genotypes were increased more or less under low N. With the extension of N stress, the number of third and fourth whorl crown roots decreased significantly, which indicated that regulation of root elongation is earlier than that of crown root initiation. As the degree of low-N stress increased, the trend of total lateral root length changes in different genotypes could be divided into three categories, indicating that the response of lateral root growth to low-N stress is genotype-dependent. With the advancement of the breeding process, the roots of modern hybrids become smaller but more responsive to low-N stress. The root phenotypes of Zhengdan958 and Xianyu335 come from different genetic models. Compared with embryonic roots, the crown roots of B73 have a more active role in adapting to low-N stress. Shoot N concentration may reflect plant internal N status, which plays a regulatory role in root morphogenesis. Full article

Maize production is deficient in arid countries such as Tunisia. To assess maize yield and estimate productivity gaps among Tunisian farmers in consideration of climate change challenges, a survey was conducted that included 50 farms in 10 governorates, focusing on agronomic practices, seed type adoptions, and socioeconomic parameters. The yield gaps related to water resources and farmers’ technical efficiency represented 26.8% and 32.9%, respectively, while for water productivity, the gaps related to water resources and technical efficiency were 32.2% and 31.3%, respectively. Hybrid varieties were among the 25% yield increase compared to local landraces. Farmers retain local landraces mainly for their food quality. Favorable climatic conditions in the northern regions of Tunisia are among the reasons for higher yield compared to the central and southern areas, which registered a yield reduction of 9.2% and 17%, respectively. The Tobit analyses showed that sowing rate, geographic location, type of variety, and fertilization are the most significant factors contributing to technical inefficiencies. For further increases in maize yield in Tunisia, improving agricultural practices, water management, and using high-yielding varieties are essential. Full article

In the framework of a Collaboration Agreement between CREA and ARSIAL, a morpho-phenological, chemical, and genetic characterization of maize populations native to the Lazio region was carried out. During 2022 and 2023, a set of 50 accessions, belonging both to ARSIAL and CREA maize collections, were multiplied in Bergamo. Morpho-phenological descriptors were recorded in the field: plant height, ear height, and male and female flowering time. The grain chemical composition in terms of protein, lipid, starch, ash and fiber was evaluated by near-infrared spectroscopy (NIRS). A double-digest restriction-site-associated DNA sequencing (ddRADseq) strategy was used to genotype the landraces. The two collections were not significantly different in terms of grain chemical composition. On the other hand, the ARSIAL and CREA germplasm showed a different distribution in the three cluster-based population structure obtained by ddRADseq, which largely corresponded to the distribution map of their collection sites. The materials from the Lazio region maintained by ARSIAL and CREA were revealed to be different. The comparison between the two groups of landraces showed the importance of characterizing germplasm collections to promote the recovery and valorization of local biodiversity. Full article

Southern corn rust (SCR) is one of the most destructive foliar diseases in maize (Zea mays L.), resulting in significant yield losses. Therefore, the continuous identification of disease-resistant germplasm and the deployment of resistant hybrids is essential for durably controlling SCR. The objective of this research was to identify and characterize resistance loci against SCR in maize to expand disease management strategies. Here, we identified a maize landrace with high resistance to SCR ‘Silunuo’ (SLN) approaching complete immunity. We backcrossed it with a susceptible inbred line, N531, to generate a stable SCR-resistant introgression line N531_R. By crossing it with F35 (a susceptible inbred line), we created a large F₂ segregating population and mapped a major SCR-resistant locus on chromosome 10, known as RppSLN. Based on the genome assembly and annotation, we found that RppSLN harbors two NBS-LRR (nucleotide binding site–leucine-rich repeat) genes, namely Zmays10G000430 and Zmays10G000440. These NBS-LRR genes were significantly induced during artificial inoculation with Puccinia polysora, suggesting that they might be candidate genes collectively contributing to the resistance level at this locus. In conclusion, this study identified a major SCR resistance locus directly isolated from a landrace, providing valuable support and information for expanding new disease-resistant germplasms and promoting the utilization of landraces. Full article

The plant seed-borne microbiome comprises microorganisms vertically inherited from the mother plant. This microbiome is often linked to early-life protection and seedling growth promotion. Herein, we compare the seed-borne bacteriomes of a commercial hybrid (Santa Helena) and a landrace maize variety (Sol da Manhã). The landrace variety displays a more diverse seed-borne microbiome, featuring a variety of taxa across samples with an average Shannon’s diversity index of 1.12 compared to 0.45 in the hybrid variety. The landrace variety also showed a greater alpha diversity of 165.8, in contrast to 144.1 in the hybrid. Although both microbiomes lack a functional nitrogen fixation apparatus, we found a remarkably distinct presence of genes associated with phytohormone production and phosphate solubilization, particularly in the landrace variety. In addition, we recovered 18 metagenome-assembled genomes (MAGs), including four from potentially novel species. Collectively, our results allow for a better understanding of the contrasting diversity between maize varieties. The higher potential for phytohormone production in landraces, the absence of nif genes in both varieties, and the identification of core microbiome taxa offer valuable insights into how microbial communities impact plant health and development. This knowledge could pave the way for more sustainable and innovative agricultural practices in crop management. Full article

Root system architecture is pivotal for the acquisition of water and nutrients in maize, serving as an essential foundation for achieving high and stable yields. Identification of the genetic components and natural variations determining root traits may facilitate molecular breeding of maize varieties with better root traits. Melatonin plays an important role in plant physiology and development. In this study, nine melatonin biosynthesis genes were re-sequenced in 348 inbred lines, 68 landraces, and 32 teosintes to investigate variations related to maize root traits. The analysis of nucleotide diversity suggested that these genes may have undergone selection, particularly within their promoter regions. Marker–trait association analysis identified 26 variants significantly associated with six root traits. Five variations within the ZmTDC4 promoter were significantly correlated with both total root length (TRL) and lateral root length (LRL). Among these, SNP-1784 explained the most phenotypic variation of root traits, including TRL and LRL, that has undergone selection throughout maize domestication and improvement. Furthermore, knockout of ZmTDC4 in maize resulted in a pronounced reduction in root length, underscoring its critical role in root development. Collectively, these findings elucidate the role of melatonin synthesis genes in root development and identified favorable alleles, thus providing key loci for breeding maize varieties with superior root systems. Full article