Genetic variability, correlation and path analysis in mutant lines of rabi sorghum [Sorghum bicolor (L.) Moench] cv. TSV-32

Abstract

The study involved 60 sorghum mutants of M3 generation derived from selfed seed of individual panicles of M2 generation from each treatment i.e. 12 mutants from each treatment viz., 100Gy, 200Gy, 300Gy, 400Gy and 500Gy along with 1 parent control (TSV-32) and 3 checks. The experiment was conducted on PG Experimental Farm at Department of Genetics and Plant Breeding, VNMKV, Parbhani, during rabi, 2023-24. The results found with significantly higher mean performance in checks for most characters, including grain production, with wide variation in GCV and PCV estimates for M3 generation and high heritability, medium GCV, PCV and GAM for grain yield per plant. Correlation analysis revealed alterations in trait relationships compared to the control, indicating that mutagenic treatments effectively modified the genetic architecture. This provides a promising strategy for yield improvement through targeted selection. Significant positive correlations between grain yield per plant and traits such as grains per primary, primaries per panicle, panicle length, panicle width, leaf area and flag leaf area demonstrated the potential of these traits to enhance yield. These findings emphasized the effectiveness of mutagenic treatments in shifting character associations favourably, offering valuable insights for breeding programs aimed at improving grain yield. Path analysis demonstrated that days to 50% flowering had the strongest positive direct effect on grain yield at both genotypic and phenotypic levels. Further, traits such as plant height, relative water content and chlorophyll content showed significant positive direct effects on grain yield at the genotypic level, highlighting their importance as key contributors to yield improvement. Thus, the study identified several promising mutant rabi sorghum lines viz., 200-19, 100-10, 200-16, 100-6, 100-1 and 500-58, which exhibited superior performance across most traits. Additionally, mutants 300-25, 100-2 and 100-9 demonstrated exceptional performance in drought tolerance-related physiological traits. These genotypes hold potential for developing high-performing varieties or hybrids with improved yield and enhanced drought tolerance in future breeding programs.