Research Journal of Agricultural Sciences
An International Journal
In semi-arid areas, the yield of post-rainy (rabi) sorghum is significantly limited by the combined impact of terminal drought and key biotic stresses, such as stem borer, aphid, shoot bug and rust. This study assessed the success of conventional backcross breeding in enhancing yield and related traits by specifically introducing multi-stress tolerance into elite rabi sorghum varieties. Nineteen advanced backcross-derived lines (BC2F4), developed using six recurrent parents and seven trait-specific donor parents, were evaluated along with their respective parents during the Rabi 2024–25 at the Centre on Rabi Sorghum, ICAR–Indian Institute of Millets Research (ICAR-IIMR), Solapur, India, using a randomized complete block design with three replications. Analysis of variance revealed highly significant differences among genotypes for all agronomic and physiological traits, indicating substantial genetic variability generated through backcross breeding. Grain yield per plant ranged from 19.04 to 57.93 g with a population mean of 39.41 g, while panicle weight varied from 24.55 to 73.40 g. In the BC2F4 lines, several surpassed their recurrent parents, with the line BC2F4-4 {(BJV-44 × SLR-31) × BJV-44} achieving the highest grain yield of 57.93 g, representing an approximate 37.7% increase over its recurrent parent, which produced 42.07 g. Similarly, BC2F4-14 {(SPV-2217 × SLR-10) × SPV-2217} (52.01 g) and BC2F4-8 {(CSV-29R × SLR-10) × CSV-29R} (50.17 g) showed yield advantages of approximately 42.0% and 4.4%, respectively, over their corresponding recurrent parents. The harvest index ranged from 37.63% to 54.92%, with the superior lines exhibiting improved assimilate-partitioning efficiency. Physiological traits also showed significant variation, with relative water content ranging from 54.62% to 82.19% and SPAD values from 35.49 to 67.68. Lines such as BC2F4-18 {(Parbhani Jyoti × RNTT- 8-32) × Parbhani Jyoti} and BC2F4-19 {(BJV-44 × RNTN-13-37) × BJV-44} maintained a higher RWC (>77%) and stable chlorophyll content, indicating enhanced drought adaptive capacity. The superior performance of the selected BC2F4 lines, surpassing both recurrent and donor parents in terms of yield and physiological efficiency, indicates transgressive segregation and successful recombination of favorable alleles. Overall, this study demonstrated that conventional backcross breeding is an effective approach for improving the yield potential and stress resilience of rabi sorghum. The identified superior backcross-derived lines are promising candidates for near-isogenic line development and multilocation evaluation of varietal release.
Research Article | Published online : 03-Jul-2026