STUDY ON COMBINING ABILITY FOR YIELD AND YIELD CONTRIBUTING TRAITS IN WATER STRESS TOLERANT GENOTYPES OF TOMATO (SOLANUM LYCOPERSICUM L.)
Sayda Rehana, Md. Harun-Or-Rashid, Naheed Zeba, Mohammad Zahir Ullah, Nabila Narzis, Asmaul Husna and Abu Bakar Siddique
The experiment was conducted to develop tomato hybrids by identifying parental lines with estimation of good combining ability effects and their variances through line x tester analysis of 44 genotypes including 32 F1 cross combinations using 12 parents after selfing (8 lines and 4 testers). The genotypes were evaluated for the yield and contributing traits. The analysis of variance (ANOVA) showed highly significant difference for all the characters suggesting the presence of genetic variability among the studied materials. The variance values of general combining ability (GCA) were lower than the specific combining ability (SCA) for all the traits except plant height. This indicates that these traits were under the control of non-additive (non-fixable) gene effects and could be exploited by heterosis breeding. The lines L1, L2, L3, L5, and testers T2, and T4 showed a desirable significant negative GCA effect for days to first flowering and days to maturity. The line L5 showed a positive significant GCA effect for most of the traits except fruit per cluster and L4 for plant height, cluster per plant, fruit per cluster, fruit per plant, fruit diameter, and yield per plant. Based on GCA effects across ten traits L4 and L5 were identified as the most promising parental lines for inclusion in hybridization programs. Outstanding crosses based on SCA effects across ten traits were L6XT1, L2XT3, L7XT2, and L4XT4. These crosses could be considered the most promising specific combiner for most traits which can be used to develop elite tomato varieties.
General Combining Ability, Specific Combining Ability, Yield Contributing Traits, HYV Tomato