Genetic studies for root and physiological traits for drought tolerance and identification of promising stable genotypes in rabi sorghum (sorghum bicolor l. Moench)
Karthik R.
Genetic studies for root and physiological traits for drought tolerance and identification of promising stable genotypes in rabi sorghum (sorghum bicolor l. Moench) - P hd (Agri) - Dharwad University of Agricultural Sciences, Dharwad 2024 - 290 32 Cms
Drought stress, exacerbated by climate change, poses a significant threat to global agriculture, necessitating climate-smart strategies and drought-tolerant crops. Sorghum, a naturally drought-tolerant cereal, plays a crucial role in food, forage, and biofuel production, particularly in water-scarce regions. However, prolonged droughts severely impact its productivity, especially during Rabi cultivation, which relies on receding soil moisture. In this study, 156 sorghum genotypes were evaluated both invitro and under field conditions with induced drought to identify high-yielding and stable drought-tolerant genotypes. Osmotic stress induced significant reductions in seedling growth parameters, such as germination rate and root and shoot length. Genotypes SPV-2831, SVD-1528R, TSLC-25 and IC-343570 exhibited superior performance during early growth under osmotic stress invitro. A high degree of variability was observed in productivity and physiological traits, highlighting potential opportunities for their improvement through selective breeding. Based on the germplasm's performance under field conditions, Thirty five genotypes were selected for root phenotyping using polyvinyl chloride (PVC) pipes to assess their drought response with a focus on root traits. A broad spectrum of variation was observed in the recorded root traits, indicating potential scope for improvement through targeted selection and breeding. The promising genotypes under moisture stress were superior for productivity traits like, panicle width, panicle weight, hundred grain weight and for physiological traits like, photosynthetic rate, relative water content and chlorophyll meter reading and also for root traits like, root length, root length density and root to shoot ratio under stress indicating their importance for drought tolerance. Physiological traits, including photosynthetic rate, transpiration rate, and relative water content, positively correlated with yield under stress, emphasizing their role in enhancing drought tolerance. Molecular diversity analysis using 50 SSR markers revealed high polymorphism, clustering the germplasm into three groups and validating the genetic variability within the genotypes. Ten SSR markers have shown high polymorphic information content (PIC) of more than 0.8. These markers are ideal for genetic diversity studies, parentage analysis, or population structure studies. We evaluated the top 20 promising genotypes for yield under stress, along with standard checks, across multiple locations and moisture regimes to identify stable genotypes with consistent performance. Genotype-by-environment interaction (GEI) analysis using the AMMI model identified IC-420956, IC-392141 and IS-24361 as stable and high yielding genotypes. The study highlights the integration of physiological, root, and productivity traits for enhancing drought tolerance in sorghum. The identified promising genotypes and key traits provide a robust framework for breeding resilient varieties, addressing the dual challenges of sustaining agricultural productivity and ensuring food security in the face of climate change. These findings affirm sorghum's potential as a critical crop for sustainable agriculture in drought-prone regions.
581.56 / KAR
Genetic studies for root and physiological traits for drought tolerance and identification of promising stable genotypes in rabi sorghum (sorghum bicolor l. Moench) - P hd (Agri) - Dharwad University of Agricultural Sciences, Dharwad 2024 - 290 32 Cms
Drought stress, exacerbated by climate change, poses a significant threat to global agriculture, necessitating climate-smart strategies and drought-tolerant crops. Sorghum, a naturally drought-tolerant cereal, plays a crucial role in food, forage, and biofuel production, particularly in water-scarce regions. However, prolonged droughts severely impact its productivity, especially during Rabi cultivation, which relies on receding soil moisture. In this study, 156 sorghum genotypes were evaluated both invitro and under field conditions with induced drought to identify high-yielding and stable drought-tolerant genotypes. Osmotic stress induced significant reductions in seedling growth parameters, such as germination rate and root and shoot length. Genotypes SPV-2831, SVD-1528R, TSLC-25 and IC-343570 exhibited superior performance during early growth under osmotic stress invitro. A high degree of variability was observed in productivity and physiological traits, highlighting potential opportunities for their improvement through selective breeding. Based on the germplasm's performance under field conditions, Thirty five genotypes were selected for root phenotyping using polyvinyl chloride (PVC) pipes to assess their drought response with a focus on root traits. A broad spectrum of variation was observed in the recorded root traits, indicating potential scope for improvement through targeted selection and breeding. The promising genotypes under moisture stress were superior for productivity traits like, panicle width, panicle weight, hundred grain weight and for physiological traits like, photosynthetic rate, relative water content and chlorophyll meter reading and also for root traits like, root length, root length density and root to shoot ratio under stress indicating their importance for drought tolerance. Physiological traits, including photosynthetic rate, transpiration rate, and relative water content, positively correlated with yield under stress, emphasizing their role in enhancing drought tolerance. Molecular diversity analysis using 50 SSR markers revealed high polymorphism, clustering the germplasm into three groups and validating the genetic variability within the genotypes. Ten SSR markers have shown high polymorphic information content (PIC) of more than 0.8. These markers are ideal for genetic diversity studies, parentage analysis, or population structure studies. We evaluated the top 20 promising genotypes for yield under stress, along with standard checks, across multiple locations and moisture regimes to identify stable genotypes with consistent performance. Genotype-by-environment interaction (GEI) analysis using the AMMI model identified IC-420956, IC-392141 and IS-24361 as stable and high yielding genotypes. The study highlights the integration of physiological, root, and productivity traits for enhancing drought tolerance in sorghum. The identified promising genotypes and key traits provide a robust framework for breeding resilient varieties, addressing the dual challenges of sustaining agricultural productivity and ensuring food security in the face of climate change. These findings affirm sorghum's potential as a critical crop for sustainable agriculture in drought-prone regions.
581.56 / KAR
