Identification of tolerant sources against high temperature in tomato (Solanum lycopersicum L.)

Abiotic stresses are major limiting factors for cultivation of tomato during summer season in Northern part of India. Tomato is successively grown in its main season but it has need for cultivation throughout season because its nutritional and commercial importance, heat stress is one of the most important constraints on crop production and adversely affects the vegetative and reproductive processes of tomato and ultimately reduces yield and fruit quality. Considering this problem, an investigation was conducted at the research farm of Indian Institute of Vegetable Research, Varanasi during the summer seasons of 2009 and 2010. Fourty eight tomato genotypes were transplanted in field at the spacing of 45 x 60 cm in three replication during second week of February in both years. All the agronomical practices were followed for raising a good crop. Horticultural and metrological data were recorded weekly, when average temperature and relative humidity range was 23.9 to 33.18⁰C and 41.5 to 45.5 %, respectively. Highly significant differences were observed among the genotypes between both seasons for most of the characters such as plant height, per cent fruit set, number of fruits per plant, fruit length, fruit diameter and average fruit weight. Among the all test genotypes only four viz. ,  Suncheery, Superbug, IIHR-2201 and Pusa Sadabahar got success in flower and fruit set at the average maximum day temperature (33.18⁰C) and relative humidity (45.5 %) and tolerate to high temperature in both years. Therefore, these heat tolerant tomato genotypes can be used for cultivation and breeding program on high temperature, successively.