EFFECT OF REPEATED POLLINATION ON TOMATO HYBRID SEED YIELD UNDER FIELD CONDITIONS.

Hybrid seed yield in tomato is strongly influenced by temperature variations. In this regard a study was conducted to estimate the effect of repeated pollination on fruit setting percentage and number of seeds / fruit under variable natural temperature during the year 2017-18 at Vegetable Research Institute, Ayub Agricultural Research Institute (AARI), Faisalabad, Pakistan. The female parent of commercial indeterminate tomato hybrid (Saandal F1) was emasculated. Pollination was done once (T1), twice (T2) and thrice (T3) keeping the interval of 24 hours between each pollination on daily basis and continued for 22 days under field conditions. Analysis of data revealed that there were significant differences among treatments, temperatures and treatment x temperature interaction for both traits. At the temperature range of 17°C - 28.6°C, there was considerable increase in fruit setting in T2 (30.2 %) and T3 (37.7 %) as compared to T1. Linear model was used to explain the behavior of T1. However, for T2 and T3, second degree polynomial model was used. Graphic representation also revealed increase in fruit setting percentage and number of seeds/fruit in to T2 and T3 treatments. However, at higher temperature range of 30°C - 33°C, T2 and T3 responded negatively with the reduction of -7.0 and -23.1% in fruit setting, respectively as compared to T1. For number of seeds/fruit, T2 and T3 showed 50.2 and 58.7% increase, respectively as compared to T1 at temperature range of 17°C - 28.6°C. However, at 30°C - 33°C temperature range, T2 exhibited 50.4% increase over T1 whereas; T3 showed decline in number of seeds/fruit (-14.0 %) in comparison with T1. It was concluded that at low temperature range (17°C-28.6°C) two times pollination (T2) could be more effective for traits that ultimately contribute in higher seed yield. [ABSTRACT FROM AUTHOR]