Combining ability analysis for growth and yield traits in semi-indeterminate tomato (Solanum lycopersicum L.) under protected condition

A diallel design was employed to assess the combining ability in semi-indeterminate tomato, aiming to improve growth and yield by identifying the desirable cross-combinations for their further exploitation. Five semi-indeterminate tomato genotypes (VRT13, EC15127, EC362941, EC521061 and EC521069) were crossed in diallel mating fashion during kharif 2020. Crosses and the parents were examined for combining ability under naturally ventilated polyhouse during Rabi 2020-2021. The GCA/SCA ratio was less than unity for most traits, indicating that non-additive gene action predominantly influenced their expression, making them suitable for hybrid breeding. However, exceptions were observed for the number of fruits per cluster, number of fruits per plant, fruit length, fruit volume, and average fruit weight, where additive gene action played a significant role. Analysing the GCA values for each parent and trait revealed that no parent consistently exhibited superior performance across all traits. The study identified EC 15127 as a good general combiner for plant height and leaf area, while VRT 13 for stem girth, early flowering, and fruits per plant. EC 521069 showed good combining ability for fruits per cluster, and EC 362941 performed well for yield per plant, fruit length, fruit diameter, fruit volume, and average fruit weight. The SCA values of the traits differed profoundly between the crosses. EC 15127 × VRT 13 had the highest SCA for plant height, EC 362941 × EC 521069 excelled in leaf area, and EC 15127 × EC 521061 showed good SCA for earliness. For fruit traits, EC 15127 × EC 521061 performed well for fruits per cluster and per plant. EC 362941 × EC 15127 contributed to yield per plant. EC 362941 × VRT 13 also excelled in average fruit weight. From the study it was concluded that best general combiners for various growth and yield related traits were EC 362941 and VRT 13. Based on SCA best specific combiner for growth and yield traits EC 362941 x EC 521069, EC 362941 x VRT 13 and EC 362941 x EC 15127. Hence, these hybrids can be exploited directly or can be used further for development of improved commercial lines.