Heterosis and combining ability studies in tomato (Solanum lycopersicum L.)
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Date
2014-08
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was carried out at Vegetable Research Centre (VRC), G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhandduring Spring-summer season of 2012 and 2013. The major objectives of the study were to know the extent of heterosis, combining ability and various genetic parameters in tomato. Thirty crosses were evolved in a line x tester mating design with 10 genotypes as female parents (lines) and 3 genotypes as male parents (testers). The hybrids, PT-11 x PT-3 and PT-20 x Punjab Chhuhara were most promising for earliness exhibiting highest negative heterosis. With respect to plant height, hybrids, PT-09-06 x PT-3 and PT-20 x Roma were most promising for tallness and dwarfness, respectively. Hybrid combination, PT-09-06 x PT-3 exhibited most promising results with respect to heterosis for fruit yield per plant and total fruit yield per hectare. Most promising hybrid for number of locules was PT-20 x Roma which exhibited negative heterosis. The best hybrids with respect to heterosis were PT-2009-02 x PT-3 for average fruit weight, PT-09-06 x Punjab Chhuhara for number of fruits per plant, PT-1 x Punjab Chhuhara for number of seeds per gram, PT-20 x Punjab Chhuhara for pericarp thickness, PT-20 x Roma for number of locules, PT-20 x Punjab Chhuhara for pericarp thickness and fruit width, PT-09-06 x Punjab Chhuhara for fruit shape index, S-06-1 x Punjab Chhuhara for TSS at turning and red ripe stage. The most promising general combiners were PT-2009-02 for fruit yield per hectare, fruit yield per plant, average fruit weight, number of locules and pericarp thickness, S-816 for plant height, branches per plant and number of locules, PT-1 exhibited the highest general combining ability for days to first harvest and days to last harvest. PT-20 for plant height, fruit length and fruit width, PT-09-06 for number of seeds per gram and number of fruit per plant, S-06-1 for TSS at immature stage, turning stage and red ripe stage. Most promising hybrids exhibiting significant sca effects were, PT-19 x Punjab Chhuharafor fruit yield per hectare, fruit yield per plant and average fruit weight, PT-41 x Punjab Chhuhara for dwarfness and number of locules, PT-19 x PT-3 and PT-11 x PT-3 for earliness, PT-41 x Roma for number of fruit per plant and tallness, PT-20 x Pumjab Chhuhara for fruit length ripe stage, fruit width for higher number of seeds per gram, PT-1 x Punjab Chhuhara for fruit width and PT-09-06 x Punjab Chhuhara for pericarp thickness.The combining ability analysis indicated the importance of both additive and non-additive gene action for different growth, yield and fruit quality characters.
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Thesis-PhD
Keywords
heterosis, combining ability, tomatoes, Solanum lycopersicum, hybrids