Seeds

The use of cattle manure wastewater for microalgae cultivation is beneficial, as it contains nutrients such as N, P, K, Mg, Zn, and Fe. Therefore, different species of algae were isolated and cultivated, and nutrient analyses were conducted, including microalgae Watanabea sp., which resulted in higher biomass production (1.5 g L⁻¹), 36% protein, and 40% carbohydrates, although the ash fraction was only 8%, the lowest. In a TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) analysis, this species was selected from among the isolates because it demonstrated the best performance for use as a biostimulant for chili germination. After that, optimal conditions were established for cultivating Watanabea sp. microalgae in six polypropylene photobioreactors with a capacity of 2.9 L were used and tested at pH values of 7.0, 7.5, 8.0, 8.5, 9.0, and 9.5, at T = 25 °C, under constant light at 850 µE∙m⁻²∙s⁻¹, and different dilution rates from 0.1 until 0.9%. The highest biomass production was achieved at pH 7.5 and a dilution rate of 0.1%, indicating that slightly alkaline conditions favored biomass accumulation. These conditions were associated with enhanced nitrate and phosphate assimilation. Furthermore, the effect of Watanabea sp. biomass on stimulating the germination of agricultural chili (Capsicum annuum L.) seeds was evaluated. Three methods of application (grounding and ungrounding freeze-lyophilized and fresh biomass) and concentrations of microalgal biomass (0.5, 1.0, and 1.5 g L⁻¹) and a control (distilled water) were used at two temperatures (25 and 35 °C). The microalgae Watanabea sp. grounding freeze-lyophilized and treated chili seeds increased the final germination percentage and slightly earlier with better vigor and root growth at both temperatures. Further studies are needed to evaluate its effects on seedling establishment and field performance.

Increasing demand for eco-friendly biopolymers requires expanding species’ genotype bases through targeted breeding and detailed screening. The amount and quality of mucilage depend on environmental conditions and on genotype. This study aimed to evaluate the influence of nine oil-type flax varieties, seed fractionation (seeds sorted according to their thickness), and cultivation year on the yield of fresh (FLSM) and lyophilised (LLSM) linseed mucilage. Agram and Astella were characterised by low production of FLSM and LLSM. Lola, Agriol, and Raciol had high levels of LLSM and FLSM production. Libra had high production of FLSM and low production of LLSM. A statistically significant difference in the amount of FLSM and LLSM between the small and large seed fractions was not observed. The results confirmed that the growing season influenced the weight of FLSM but not LLSM. However, differences in the growing season were observed between varieties. The results highlight that some morphological traits in linseeds (solidity, small size of seed, and area of seed) can serve as indicators of lyophilised mucilage production. Differences in the morphological structure of the lyophilised mucilage on macro- and microscopic levels were observed. Our study highlights the need for detailed screening of the flax genetic resources, given the enormous potential of linseed mucilage and its properties.

Climatic variability and recurrent drought increasingly threaten rainfed sunflower production in south-eastern Europe, highlighting the need for practical adaptation strategies. This study evaluated the effects of two sowing dates, early sowing on 24 March (SD1) and conventional sowing on 14–15 April (SD2), corresponding to the common sowing practice in the region, on sunflower productivity and seed quality during three consecutive growing seasons (2023–2025) under rainfed no-till conditions in the Dobrogea Region of Romania. A randomized complete block design with three replications was used, while all agronomic practices remained identical except for sowing date. Crop performance was assessed through yield, oil content, plant density, plant height, seed weight per capitulum, thousand-grain weight (TGW), test weight, and seed moisture, and data were analyzed using ANOVA, Student’s t-test, Pearson correlation, and redundancy analysis (RDA). Early sowing resulted in higher mean values than conventional sowing, increasing seed yield by 25.4% (1341.65 vs. 1070.20 kg ha⁻¹), oil content from 44.80% to 45.90%, TGW from 47.39 to 53.96 g, test weight from 37.46 to 41.64 kg hL⁻¹, and seed weight per capitulum from 34.45 to 38.72 g. The magnitude of the sowing-date response varied among growing seasons, highlighting the importance of considering naturally occurring interannual variability when interpreting treatment effects. RDA indicated that precipitation showed the strongest association with variation in agronomic performance. Advancing sowing by approximately three weeks was associated with improved crop performance across the three growing seasons, which were characterized by naturally occurring interannual meteorological variability. These findings provide site- and hybrid-specific evidence to inform sowing-date decisions for rainfed no-till sunflower production.