Heterosis for Fruit Yield and Heat Tolerance Traits in Tomato (Lycopersicon Lycopersicum Mill.) Under Field Conditions

Field experiments were conducted at the National Horticultural Research Institute, Bagauda in the Sudan Savannah and Institute for Agricultural Research, Samaru in the Northern Guinea Savanna ecological zones of Nigeria between July-October, 2014 rainy season to estimates heterosis for fruit yield and heat tolerance traits of tomato under field conditions. The experiment comprised two heat tolerant (Icrixina and Rio Grande) and four heat susceptible tomato (Tima, Tropimech, Petomech and Roma Savana) which were crossed using half diallel mating design in the screen house. The resultant 15 hybrids, their parental lines along with four checks were laid out in partially balanced lattice design with three replications. Analysis of variance revealed significant variation among the genotypes for all traits except fruit diameter and cell membrane thermostability, indicating sufficient variability existed among the genotypes. The cross combinations Icrixina × Rio Grande, Icrixina × Tima, Icrixina × Roma Savana and Icrixina × Petomech were found heterotic over better parent for fruit yield and heat tolerance traits (Number of branches per plant, number of clusters per plant, number of flowers per cluster, number of fruits per cluster, number of fruits per plant, percentage fruit set and chlorophyll content) among the hybrids. These hybrids were superior over better parent have the potentiality to be exploited for developing commercial heat tolerant tomato hybrid under field conditions.