Jornal de Genética e Melhoramento Vegetal

Abstrato

Analysis of Tomato Agronomic Traits using Generation Mean

Francis Kamau Kathimba, Paul Macharia Kimani, Rama Devi Narla, Leonard Muriithi Kiriika

This study aimed at determining inheritance of agronomic traits viz. plant height, days to 50% flowering, inter truss spacing and number of trusses per plant in local and introduced tomato lines. Six generations; P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂ were developed for each of four bi-parental crosses between five genetically diverse parental lines; AVTO1429, Roma VF, AVTO1424, AVTO1314 and Valoria. A split-plot design, crosses as main plots and generations as subplot with three replicates was used in two sites during 2019, long rain season. Cross Roma VF x AVTO1424 and Roma VF x AVTO1314 were the earliest to 50% flowering in 33 days while Roma VF x Valoria select was the latest in 35 days. F1 hybrid of Roma VF x AVTO1314 showed flowering within 32 days whereas 35 days in P1 (Roma VF). Mwea Station had the tallest mean plant heights of 62cm (at 50% flowering) compared to Kabete Station with 48cm in all crosses and generations. A significant increase (>10%) in plant height at 50% flowering in comparison to parental genotypes was registered in F1 generations. Final plant height across the environments ranged from 82cm for shorter parent (Roma VF) of Roma VF x AVTO1429 to 120 cm for taller offspring, BC₁P₁. Notably, both inter truss spacing and number of trusses per plant were not significantly different (P≤0.05) for crosses evaluated in both sites. Agronomic traits which showed significant genotype x environment interaction in Roma VF x AVTO1314 were days to 50% flowering, final plant height, and number of trusses per plant whereas, in Roma VF x AVTO1429 it was plant height at 50% flowering 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 the traits were inherited.