Studies of gene action and heritability of the percentage of fruiting in tomato, cultivar Nagcarlang under conditions of heat stress

Abstract

Poor fruit set induced by high temperatures is the main cause of yield losses in tropical and subtropical regions. The present study was aimed to estimate gene action and the heritability of fruit set in heat tolerant Nagcarlang cultivar. Thus, fruit set percentage was evaluated over the optimal and spring-summer periods of the F1, F2 populations and the backcrosses with each parent of the cross between Nagcarlang and the beat sensitive AN-104-1 inbred line. Mean percentage of fruit set of the F exceeded midparent values are not significantly different from those of Nagcarlang, indicating complete dominance from heat tolerance. Generation means analysis showed that a model including simple and additive dominance is not adequate to explain inheritance of percentage of fruit set. The best fitting model included epistatic interactions. Heritability estimated in the broad sense was intermediate. The narrow sense heritability was lower in springsummer periods. The low narrow sense heritability for percentage of fruit set suggest that simple plant selection in the F₂ for high temperatures tolerance from crossed involving Nagcarlang is not effective to predict the progress by selection in tomato crosses in order to obtain heat tolerant  cultivars and the selection should be based on in more advanced generations.