Studies on heterosis using heat tomato tolerant lines

Abstract

Fruit set in tomato is reduced markedly, when average maximum day and night temperatures go above 32°C and 21°C, respectively. In North-Western plains of India, if the tomato crop is transplanted in March, flowering and fruit set period coincides with high day (~37°C) and night temperatures (~25°C), which markedly reduces fruit yield and quality. Therefore, the present study was carried out to identify the heterotic hybrids in tomato, tolerant to heat stress conditions. The 66 F1 hybrids showed useful heterosis for almost all characters studied. Based on per se performance and heterosis estimates under high temperature condition, the best performing cross is LST-36-1 × LST-35-1 (P6 × P7) for maximum fruit firmness; LST-37-1 × LST-36-1 (P5 × P6) for maximum Endosperm Utilization Efficiency (EUE) and the cross combination, LST-6 × CLN 5915-206 (P8 × P11) for maximum total fruit yield. The hybrid, P8 × P11 had fruit yield of 1.17 kg per plant and it showed 193.3 per cent increase over better parent and 291.11 per cent increase over standard check TH-1.