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

Relationship between assimilatory surface, growth rates and net photos ynthetic rate (P(N)) of the tomato (Lycopersicon esculentum Mill.) hyb rid FM Hy-1 and its parents IHR 932 and IHR 837 was studied under cont rolled environmental conditions. Total leaf area and biomass were grea ter in FM Hy-1 than in its parents. According to growth analysis, hete rosis greatly affected early development of the hybrid. Greater net as similation rate (NAR) of the hybrid during early growth suggested a gr eater 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 maximu m P(N). Early growth of the hybrid and higher growth rates were respon sible for higher dry matter production and yield per plant.