COMBINING ABILITY OF TOMATO GENOTYPES FOR IMPROVED SALT TOLERANCE
The combining ability of four tomato genotypes (Lycopersicon esculentum Mill.) for salt tolerance was determined by investigating the progeny from a 4 × 4 diallel cross. Sixteen progenies (F1s, selfs and reciprocals) were evaluated at three levels of salinity (0%, 1.0%, 1.5%) in a complete block design with four replications under greenhouse conditions. The analysis of the genetic component revealed that the mode of inheritance of salt tolerance appeared to be different to that of plant characters and salinity levels as measured by plant height and fruit yield components. However, the fruit count was consistently controlled by additive gene effects. The specific crosses Moneymaker (MM) × Red Alert (RA) and Ailsa Craig (AC) × Gardener's Delight (GD) produced the highest yield. The small-fruited parents, Red Alert and Gardener's Delight, had higher general combining ability value for salt tolerance than the large-fruited, Ailsa Craig and Moneymaker, for fruit yield components. RA and GD were superior parents in transmitting salt tolerance. The study revealed that plant selection could be used to improve varietal performance for salt tolerance. It is also suggested that the potential variation in commercial cultivars could be exploited to improve adaptability to more saline growing conditions till resistant cultivars are developed through crosses with the wild species or genetic transformation with optimum management practices.