Genetic Variability Studies and Isolation of Transgressive Segregants Adaptable to Moisture Stress in Bread Wheat (Triticum aestivum L.)
- Dharwad University of Agricultural Sciences 2024
- 143 32 Cms
ABSTRACT
The study aimed to identify transgressive segregants with enhanced yield under moisture stress. The parents, UAS 375 (a rainfed variety), CWYT_609 (with strong root architecture), and HTWYT_66 (NDVI > 0.74 under stress), were hybridized to develop two populations: UAS 375 × CWYT_609 and UAS 375 × HTWYT_66. A total of 125 F3:4 progeny lines were evaluated under restricted irrigation during the Rabi 2023-24. Significant genetic variation among genotypes was observed, allowing for effective selection. Traits like peduncle length, flag leaf length, grains spike-1 and grain yield exhibited high heritability and genetic advance, suggesting additive gene action, making them ideal for direct selection. Positive but significant correlations between grain yield and traits such as plant height, peduncle length, flag leaf length, spike length, tillers per plant, 1000 grain weight and grains spike-1 indicated that improving these traits could boost yield under moisture stress. Early maturity was negatively associated with yield, suggesting that early-maturing varieties perform better in stress conditions. Path coefficient analysis revealed grains per spike (0.349) in the UAS 375 × CWYT_609 cross and 1000 grain weight (0.409) in the UAS 375 × HTWYT_66 cross as key traits for selection. Principal component analysis showed that four components explained 65.4 per cent of the variation in UAS 375 × CWYT_609 and three components explained 61.5 per cent in UAS 375 × HTWYT_66. Hence, carefully choosing genotypes from such groups can improve ability of wheat to survive moisture stress. Selection indices based on traits like plant height, grains spike-1, 1000 grain weight and grain yield resulted in high genetic gains and selection efficiency. Promising segregants, F4: 23-24 (77) in UAS 375 × CWYT_609 and F4: 23-24 (11) and F4: 23-24 (71) in UAS 375 × HTWYT_66, demonstrated high yields making them potential donor lines for breeding under moisture stress conditions.