Mashenene Malima

This study characterized the fatty acid composition of cottonseed oil in six commercial cotton varieties from Türkiye and fourteen F2 hybrids, focusing on palmitic, stearic, oleic, linoleic, and linolenic acids. Genetic variation was quantified to assess parental–hybrid relationships and identify genotypes with potential for improving cottonseed oil quality. Fatty acid composition was determined using gas chromatography–mass spectrometry (GC–MS). Significant variation was detected among parental varieties and F2 hybrids. In parental varieties, palmitic acid ranged from 3.4 to 29.9%, stearic acid from 0.2 to 1.3%, oleic acid from 12.2 to 22.4%, linoleic acid from 53.5 to 66.0%, and linolenic acid from 0.0 to 12.4%. Among F2 hybrids, palmitic acid ranged from 5.2 to 45.5%, stearic acid from 0.2 to 5.6%, oleic acid from 0.9 to 20.2%, and linoleic acid from 50.3 to 89.3%; linolenic acid was not detected. Correlation analysis indicated a moderate positive association for stearic acid (r = 0.45, p = 0.62), while other fatty acids showed weak or negligible correlations. Principal component analysis and hierarchical clustering revealed strong concordance, grouping genotypes with similar fatty acid profiles. Overall, these genotypes provide valuable genetic resources for breeding programs targeting improved cottonseed oil composition, enhanced nutritional quality, and desirable fatty acid profiles.

A two-year field study underscores the importance of integrating genotype selection with optimized Mepiquat Chloride (MC) management to enhance cotton performance under a split–split–plot design. Significant genotype × environment × management interactions were observed in cotton growth, yield, and fiber quality responses MC application. Plant height was significantly affected by year × variety interaction (p < 0.01), with the tallest plants in Selin (2023) and Sezener (2022). Leaf area was higher in 2022, while 800 cc. ha^-1 enhanced leaf expansion. Monopodial branches were significantly greater in 2023 (9.59 plant^-1), with early MC application favoring branch initiation. Seed cotton yield was peak in Selin (3623 kg ha^-1), 25% greater than Sezener, with split application (400 + 400 cc. ha^-1) yielding best results. Boll number and individual fiber weight were higher in Selin and Sezener, respectively, with the latter showing a 48% increase under 400 cc. ha^-1. Seed index was significantly higher in Sezener, and fiber moisture increased in 2023 (8.94%). Fiber quality traits revealed pronounced year, genotype, and application timing effects: fiber length peaked in Sezener (30.33 mm), elongation reached 5.80%, and micronaire increased to 4.89 µg inch^-1 under split MC application. Fiber strength increased by 13.07% in 2023, and while uniformity (85.62%) maximized with later application. Short fiber content decreased by 14.81% in 2023. These findings highlight that MC concentration, timing, and genotype interactions significantly modulate morphophysiological traits, yield components, and fiber quality, with split or moderate-dose applications enhancing productivity and fiber properties under Mediterranean conditions.

Objective: A field study was undertaken to examine the effect of reduced Mepiquat chloride (MC) dosage applied at different times to enhance the yield and quality attributes of cotton at the Eastern Mediterranean Agricultural Research Institute, Adana, Türkiye, during the 2022 cropping season. Material and Methods: A split-split plot experiment following a randomized complete block design (RCBD) with three replications was employed.Varieties (Sezener and Selin) were assigned to the main plots, application times (before and after flowering) to the sub-plots, and MC concentrations (0, 40, 40+40 and 80 cc/da) to the sub-sub-plots. Results: Results shown that Sezener outperformed Selin across metrics: higher fiber yield (490.6 vs 447.5 kg/ha), reflectance (69.8 vs 63.5), and yellowness (11.9 vs 10.8). Under Sezener, the 80 cc/da dosage at 60 days after sowing maximized yield (530.2 kg/ha). Selin showed poorest yield (360.3 kg/ha) and highest trash (2.60%), while Sezener had lowest (0.57%). Mepiquat chloride doses effected quality parameters differently for both varieties. The effect changed within application time. It has been determined that the application of Mepiquat chloride has different effects on the quality parameters in two varieties, and the effect varied according to the time of application. As a matter of fact, in the yellowness parameter, unlike other quality parameters, Selin variety had the lowest, while Sezener had the highest value. Conclusion: Although most effects were not statistically significant, certain variety-application time interactions revealed practical differences that may inform future studies. Therefore, to maximize monetary returns, further research is needed to enhance yield and quality parameters in the Mediterranean region of Türkiye. In addition, more comprehensive studies should be carried out to understand the change in the effect of Mepiquat chloride application on the basis of varieties.

Germination and seedling growth periods have a very important function in plant life. Especially in cases where abiotic stress conditions occur, these periods are of vital importance for the sustainability of plant life. Taking this into account, this research was conducted to determine the most suitable temperature for germination and seedling growth parameters of cotton varieties. In this research conducted under controlled conditions, germination and seedling development parameters of two cotton varieties (May-344 and Candia) were tested at 8 different temperature levels (8, 12, 16, 20, 24, 28, 32 and 36°C). It was determined that the germination percentage was 45.17-16.17%, the germination time was 4.06-3.94 days and the emergence rate index was 1.89-0.58 in May-344 and Candia cotton varieties, respectively. Moreover; root length 37.89-16.43 mm, stem length 44.69-41.00 mm, root fresh weight 22.40-19.51 mg, stem fresh weight 90.37-131.80 mg and the root/stem ratio was 0.26-0.16 mg/mg in May-344 and Candia cotton varieties, respectively. The results of the experiment revealed that most of the tested parameters were significantly affected by temperature. The highest germination rate, as the average of the two varieties and for both varieties separately, was obtained at 20 oC and no germination occurred at 8 oC. Except root to shoot ratio, other seedling growth parameters were maximum between 20-32 oC and decreased at higher temperatures.