Heterosis and combining ability evaluation for fruit yield and maturity in tomato under mid hill conditions of Himachal Pradesh.

Abstract

The hybrid vigour and combining capacity of nine (9) elite tomato genotypes and their 36 hybrids (developed via diallel crossing, excluding reciprocals) were evaluated for nine agronomic characters in the mid-hill conditions in Himachal Pradesh at the RHR&TS, Bajaura-Kullu. A commercially successful hybrid, Naveen 2000+, was used as a control to assess heterosis and identify parents with strong combining ability, ideal for developing new F₁’s with high yield potential, earliness, quality traits and off-season suitability. The study found that most traits displayed significant levels of heterosis when compared to both the superior parent and the commercial check variety (Naveen-IAHS). The crosses Arka Abha × H-7998 and Solan Lalima × BajT-4 showed the greatest degree of heterosis for early maturity, whereas Solan Lalima × BajT-4, Solan Lalima × Arka Meghali and H-7998 × BajT-4 demonstrated the highest fruit yield per plant. Additive and non-additive genetic effects influenced trait expression, with additive effects being dominant. Although GCA and SCA were uncorrelated, GCA sums predicted heterosis for certain traits more effectively than SCA. Solan Lalima and BajT-4 were identified as the best general combining parents for fruit yield, with BajT-4 also showed superior performance in terms of fruit number per plant, fruits in cluster and fruit average weight. Specific crosses, including Solan Lalima × BajT-4, Solan Lalima × Arka Meghali and H-7998 × BajT-4 were found to be optimal for maximizing marketable yield. Predictability ratios (<1 for most traits) highlighted the predominance of non-additive gene action, providing valuable insights for selecting superior parents and hybrid combinations.