Studies on Heterosis Using heat Tolerant Lines in Tomato

Twelve parents half diallel set involving heat tolerant lines were studied for yield and yield attributing traits under heat stress conditions. The resulting sixty six F₁ hybrids were tested for heterosis over respective better parents. Useful heterobeltiosis was observed for almost all the characters studied. Out of 66 crosses, studied for number of flowers per cluster, 14 crosses showed significant positive heterosis over respective better parents. For harvesting span, the cross combination P₈ x P₁₁ took longest duration of 31 days and showed 30.99 per cent heterosis over better parent. The cross combination P₆ x P₇ showed maximum heterobeltiosis of 29.13 per cent for days from fruit setting to turning stage. The cross combinations P₁ x P₂, P₈ x P₁₁ and P₈ x P₁₂ were the best crosses for marketable yield and they showed 160.8, 328.8 and 156.09 per cent heterosis over better parents, respectively.