Genetic studies in bread wheat (Triticum aestivum L.) under moisture - stress conditions
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Date
2020
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CSKHPKV Palampur
Abstract
The present investigation entitled “Genetic studies in bread wheat (Triticum aestivum L.) under moisture - stress conditions” was undertaken during rabi 2018-19 at Rice and Wheat Research Centre, Malan with the objectives to study genetic parameters for moisture-stress tolerance and yield attributes in wheat and also the inter-relationships among agro-morphological and biomass accumulation traits. The experimental material comprised of thirty five diverse genotypes and data were recorded on the traits, namely, grain yield per plant (g), grains per spike, 1000-grain weight (g), flag leaf area (cm²), plant height (cm), days to 50 per cent flowering, days to 75 per cent maturity, biological yield per plant (g), harvest index (%), stem reserve mobilization (%); drought susceptibility index and drought response index under field conditions. Root length (cm), coleoptile length (cm), shoot length (cm), seedling vigour index and seedling survival after desiccation were recorded only under controlled conditions at seedling stage.
Analysis of variance revealed that mean squares due to genotypes were significant for all the traits studied under field and controlled conditions, which indicated the presence of sufficient genetic variability amongst genotypes for these traits. High heritability and genetic advance were observed for biomass at anthesis both under non-stress and moisture-stress conditions indicating importance of this trait for selection. Flag leaf area under E1 and E2 and biomass at tillering under E1 exhibited high heritability coupled with moderate genetic advance, indicating moderate expected genetic gain through selection under environments. Based on correlation coefficient and path analysis, biomass at maturity and harvest index emerged to be the important selection criteria under both non-stress and moisture-stress conditions because they had a high direct effect and indirect effect by other traits on grain yield. However, grains per spike, flag leaf area, stem reserve mobilization and days to flowering also appeared to be the important traits based on significant correlations and indirect contributions towards grain yield under moisture-stress conditions. Among the seedling traits, shoot length and coleoptile length showed high heritability coupled with high genetic advance, indicating high genetic response to selection. Whereas, root length and seedling vigor index showed high heritability coupled with moderate genetic advance, indicating moderate response to selection. Root length and seedling survival after desiccation showed significant positive correlation with drought response index and grain yield under moisture-stress conditions, implying thereby that selection for these traits may be fruitful to select high yielding genotypes. Ranking of the genotypes based on DRI and DSI under field and controlled conditions indicated that drought tolerance of ‘JW 3020’ was most tolerant followed by HPW 318, IC 594377, UP 2526, Tarmori, HPW 89, HPW 314, WH 1080 and Desi Mundla. These genotypes may be used in hybridisation programme for development of drought tolerance genotypes.