Estimation of magnitude of heterosis for seed yield and various morphological traits in sunflower hybrids (Helianthus annuus L.) using L × T mating design

The hybrids were developed by employing line × tester mating design involving four lines and eight testers during Rabi 2023-2024. The resultant 32 hybrids along with 12 parents and one check Mahodaya were evaluated in randomized block design with three replications and four meter single raw of each genotype under four various environments viz., Centre for Oilseeds Research Station, SDAU, Sardarkrushinagar (E1, 5th March 2024), Regional Research Station, Kothara (E2, 7th March 2024), Centre for Maize Research Station, Bhiloda (E3, 16st March 2024) and College of Agriculture, Tharad (E4, 06st March 2024) during summer 2024. The analysis of variance in pooled over various environments unveiled of substantial amount of genetic variability among the genotypes for all twelve traits. This significant genetic variability manifested the potential for exploiting diverse genetic resources for further enhancement of sunflower cultivars. Notably, the existence of overall heterosis became apparent, with the significant genotype × environment interactions observed for all the traits, indicating a differential response of genotypes to varying environmental conditions. Significant standard heterosis was observed for seed yield per plant, rendering the potential benefits of heterosis breeding in achieving superior yield performance. Noteworthy hybrids, such as COSF 7A × GMU 756 at Sardarkrushinagar (E1); COSF 6A × R-630 at Kothara (E2), Tharad (E4) as well as in pooled and COSF 3A × RHA-297 at Bhioloda (E4) environments recorded the highest significant positive standard heterosis for seed yield per plant, which indicated specific performance of these hybrids across different growing conditions.