Heterosis and Combining Ability via Line × Tester Analysis for Seed Yield and Yield-Contributing Traits in Safflower (Carthamus Tinctorius L.)

Abstract

Aims: The experiment was conducted to study the general combining ability (GCA) of the parental lines and the specific combining ability (SCA) of the hybrids. Study Design: Randomised block design Place and Duration of Study: The study was conducted at the Field Experimentation Centre of the Department of Genetics and Plant Breeding, Naini Institute of Agriculture, Sam Higginbottom University of Agriculture, Technology & Sciences, Prayagraj (UP), during 2022-23 and 2023-24. Methodology: Four lines and five testers raised in a crossing block were crossed using the line x tester method to produce 20 hybrids during the year. The resultant 20 hybrids, along with nine parents and the check Sharda, were evaluated in a randomised block design with three replications. Results: The analysis of variance showed highly significant differences among the 30 genotypes for all the characters studied. The hybrid SSF-1870×SSF-1240 showed the highest standard heterosis for seed yield (27.95%), number of capitula (23.83%) and number of secondary branches (17.46%). The hybrid SSF-1870×SSF-18123 showed the maximum relative heterosis of 67.84% for seed yield. The hybrid SSF-1871×SSF-1704 showed the maximum standard heterosis for oil content (14.15%), and the highest heterosis over the mid-parent for oil content was recorded by the hybrid SSF-1870×SSF-1872 (32.89%). Combining ability analysis indicated that the mean sums of squares due to SCA were higher than those due to GCA for all the traits studied, indicating the predominance of non-additive gene action among the hybrids. Among the parents, SSF-1870 and SSF-1883 emerged as consistently good general combiners across several traits, whereas none of the hybrids exhibited consistently high specific combining ability across the majority of the traits studied. Conclusion: Among the parents, the line SSF-1870 and the tester SSF-1883 were found to be good general combiners for most of the traits, including number of secondary branches, number of capitula, harvest index, seed yield per plant, and number of seeds per capitulum.