Analysis of tomato agronomic traits using generation mean

Information on inheritance of agronomic traits and lack of tomato (Solanum lycopersicum L.) a robust breeding programme in Kenya, has led to dependency on imported tomato varieties. The objective of this study was to assess the inheritance of growth attributes of tomato lines in Kenya and identify cross family with great potential for further breeding. Six generations; namely P1, P2, F1, F2, BC1P1 and BC1P2‚ were developed from five parental lines. A split-plot design with crosses as main plots and generations as subplots was used in two sites (Kabete Field Station and Mwea Research Station), located in Kenya. Cross Roma VF x AVTO1424 and Roma VF x AVTO1314 were the earliest (33 days) to reach 50% flowering; while BC1P2‚ of Roma VF (38 days) was the latest to flower. Mwea Station had plants with the tallest plants, with a mean height of 62 cm at 50% flowering, compared to Kabete Station with a mean height of 48 cm. A significant increase (>10%) in plant height was registered in F1 generations compared to parental lines. Plant height at maturity across the environments ranged from 82 cm for shorter parent, Roma VF, to 120 cm for taller offspring BC1P1. Significant genotype x environment interactions were observed in Roma VF x AVTO1314 and Roma VF x AVTO1429 for days to 50% flowering, plant height, and number of trusses per plant. The importance of gene effects for agronomic trait inheritance was in additive and dominance-additive portions, which implied that traits were inherited

HETEROSIS AND COMBINING ABILITY FOR RELATED TRAITS IN TOMATO

Tomato ( Solanum lycopersicum L.) yields have continued to plummet in Kenya due to biotic stresses and reliance on low yielding varieties. This study aimed at determining heterosis and combining ability for fruit yield and yield components among tomato genotypes and select F1 hybrids combining high fruit yield and other market demanded traits under Kenyan conditions. Ten parental genotypes and their 45 F1 hybrids were studied using 10 710 half diallel mating design, excluding the reciprocals and the self\u2019s. The experiment was set up in Kiambu and Kirinyaga Counties in Kenya. Out of 45 F1 hybrids evaluated, 89% had reduced (negative heterosis) days to 50% flowering and 11% days to maturity, compared to their better parents. Higher heterosis (-9%) was recorded on days to flowering in AVTO1429 x Cal J VF) and -5% for maturity in Roma VF x AVTO1314. All the F1 hybrids had positive heterosis for number of trusses per plant and fruit yield. F1 hybrid AVTO1429 x AVTO1314 had the highest positive heterosis of 114.39% for fruit weight per plant yield. The results showed high significant difference among the ten genotypes for general and specific combining ability effects (male x female) for all the traits evaluated. There was additive and non-additive gene action for the traits, which are important aspects in developing a tomato breeding programme.Les rendements de la tomate (Solanum lycopersicum L.) ont continu\ue9 de chuter au Kenya en raison des stress biotiques et de la d\ue9pendance aux vari\ue9t\ue9s qui donnent le faible rendement. Cette \ue9tude visait \ue0 d\ue9terminer l\u2019h\ue9t\ue9rosis et \ue0 combiner la capacit\ue9 de rendement en fruits et les composants de rendement parmi les g\ue9notypes de tomates et s\ue9lectionner des hybrides F1 combinant un rendement \ue9lev\ue9 en fruits et d\u2019autres caract\ue9ristiques demand\ue9es par le march\ue9 dans les conditions kenyanes. Dix g\ue9notypes parentaux et leurs 45 hybrides F1 ont \ue9t\ue9 \ue9tudi\ue9s \ue0 l\u2019aide d\u2019un plan d\u2019accouplement 10 7 10 demi-diall\ue8le, \ue0 l\u2019exclusion de la s\ue9lection r\ue9currente r\ue9ciproque et autof\ue9condation. L\u2019exp\ue9rience a \ue9t\ue9 mise en place dans les comt\ue9s de Kiambu et Kirinyaga au Kenya. Les 89\ua0% de 45 hybrides F1 \ue9valu\ue9s avaient des jours r\ue9duits (h\ue9t\ue9rosis n\ue9gatif) \ue0 50\ua0% de floraison et 11\ua0% de jours jusqu\u2019\ue0 maturit\ue9, par rapport \ue0 leurs meilleurs parents. Une h\ue9t\ue9rosis plus \ue9lev\ue9e (-9 %) a \ue9t\ue9 enregistr\ue9e sur les jours pr\ue9c\ue9dant la floraison chez AVTO1429 x Cal J VF) et -5 % pour la maturit\ue9 chez Roma VF x AVTO1314. Tous les hybrides F1 avaient une h\ue9t\ue9rosis positive pour le nombre de grappes par plante et le rendement en fruits. L\u2019hybride F1 AVTO1429 x AVTO1314 pr\ue9sentait l\u2019h\ue9t\ue9rosis positive la plus \ue9lev\ue9e de 114,39 % pour le rendement en poids de fruit par plante. Les r\ue9sultats ont montr\ue9 une diff\ue9rence significative \ue9lev\ue9e entre les dix g\ue9notypes pour les effets de capacit\ue9 de combinaison g\ue9n\ue9raux et sp\ue9cifiques (m\ue2le x femelle) pour tous les traits \ue9valu\ue9s. Il y avait une action g\ue9nique additive et non additive pour les traits qui sont des aspects importants dans le d\ue9veloppement d\u2019un programme de s\ue9lection de tomates