~ 1992 ~ International Journal of Chemical Studies 2018; 6(2): 1992-1996 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2018; 6(2): 1992-1996 © 2018 IJCS Received: 22-01-2018 Accepted: 26-02-2018 Nidhish Gautam Department of Vegetable Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, H.P., India Manish Kumar Department of Vegetable Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, H.P., India Dharminder Kumar Department of Vegetable Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India Sandeep Kumar Department of Vegetable Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India Amit Vikram Department of Vegetable Science, Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India Rajesh Kumar Dogra Department of fruit science, Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India Shikha Sharma Department of Biotechnology Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India Correspondence Nidhish Gautam Department of Vegetable Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India Combining ability and gene action studies for important quality traits in tomato ( Solanum lycopersicum L.) Nidhish Gautam, Manish Kumar, Dharminder Kumar, Sandeep Kumar, Amit Vikram, Rajesh Kumar Dogra and Shikha Sharma Abstract Diallel analysis revealed highly significant differences among different tomato genotypes for number of locules per fruit, pericarp thickness, whole fruit firmness, total soluble solids, ascorbic acid and lycopene content. Significant mean squares for general combining ability (GCA) and specific combining ability (SCA) indicated joint role of both additive and non-additive gene effect for the expression of quality traits. The predictability ratio of GCA/SCA variance was found less than one for number of locules per fruit, pericarp thickness, whole fruit firmness, total soluble solids, ascorbic acid and lycopene content showing preponderance of non-additive gene effects. Among parents, UHFT-9, UHFT-10 and UHFT-55 were found good general combiners there for traits studied whereas hybrids viz. UHFT-9 x Solan Lalima, UHFT-10 x Solan Lalima, UHFT-22 x Solan Lalima and UHFT-55 x EC-2798 had more and significant SCA effects for suggesting a scope for the presence and exploitation of heterosis, with regards to the various quality traits in the crosses. Keywords: Diallel (excluding reciprocals), Gene action, General Combining Ability (GCA), Specific Combining Ability (SCA), Additive and non additive effects Introduction Tomato (Solanum lycopersicum L.) is second most important fruit vegetable crop under cultivation after potato belonging to the family Solanaceae. In Himachal Pradesh it is grown as summer as well as off season vegetable. Tomato is a rich source of vitamin A, C and minerals like Ca, P and Fe (Dhaliwal et al., 2003) [8] . Tomatoes are major contributors of antioxidants such as carotenoid (especially, lycopene and β-carotene), phenolics, ascorbic acid (vitamin C) and small amounts of vitamin E in daily diets (Rai et al., 2012, Gautam et al., 2016) [12, 11] . Tomato is highly self pollinated (Gautam et al., 2018) [12] . Present day Pure line varieties of tomato are unable to meet the domestic demand due to their low genetic potential, susceptibility to various biotic and abiotic stresses, limited area under cultivation, intolerance to water stress and competition with major crops (Saleem et al., 2011; Sajjad et al., 2011; Akhtar et al., 2012) [22, 21, 2] . In contrast, Hybrid variety (F1 population) In general gives 3 to 4 times more yield along with good quality fruits to that of Pure line variety (Tiwari & Choudhury, 1986). The superior characters of F1 hybrids are also lost during future generations while purifying and stability of segregating generation therefore; growers need to buy single generation hybrid seed every time when they grow tomato plant. Main reason for slow progress in tomato hybrid breeding in India is lack of good general combiner parents to be crossed for exploitation of heterosis. India is facing higher imports of tomato seed due to limited quality seed producing agencies that can fulfill domestic seed requirements. Different biometrical techniques are now available to select successful parental lines to be involved in crossing and suitable for hybrid seed production. Diallel analysis technique developed and illustrated by Hayman (1957) [15] and Jinks (1956) [16] provides guideline for the assessment of relative breeding potential of the parents and has been extensively used to identify good combiner parents in various crops like hot pepper (Legesse, 2001) [19] , tomato (Chishti et al., 2008) [5] and okra (Wammanda et al., 2010) [30] . This technique provides precise information on gene action controlling the expression of desired traits. Based on this information on combining ability and gene action, the desirable selected lines can be combined either to exploit hybrid vigor by accumulating non-additive gene effects or to evolve cultivars