LEAF-AREA, GROWTH AND PHOTOSYNTHESIS IN RELATION TO HETEROSIS IN TOMATO

Relationship between assimilatory surface, growth rates and net photosynthetic rate (P(N)) of the tomato (Lycopersicon esculentum Mill.) hybrid FM Hy-1 and its parents IHR 932 and IHR 837 was studied under controlled environmental conditions. Total leaf area and biomass were greater in FM Hy-1 than in its parents. According to growth analysis, heterosis greatly affected early development of the hybrid. Greater net assimilation rate (NAR) of the hybrid during early growth suggested a greater P(N) per unit leaf area. Maximum P(N) was observed in the hybrid during the flowering stage. Among the parents, IHR 837 had the maximum P(N). Early growth of the hybrid and higher growth rates were responsible for higher dry matter production and yield per plant.