Hybridisation between cherry tomato (small fry) and Petomech for shortened fruit maturation, size and earliness

Abstract

Tomato (Lycopersicon esculentum var. cerasiforme) is among the most important vegetable crops grown world wide providing good nutritional requirements and boost incomes, especially in sub-Saharan Africa. The objective of this study was to determin the heritability of shortened fruit maturation (SFM) period in a hybrid from a cross between cherry (Small fry) tomato and Petomech. A field experiment was carried out at the Crops Research Institute (CRI), Kwadaso. A cross was made between Petomech and Small fry. Fruit maturation period (FMP) (days from anthesis to the breaker stage of fruit Colour) was 42 days for Small fry and 52 days for Petomech. Parental, F₁, F₂, and backcross generations differed in FMP, yield, estimates of broad- and narrow-sense SFM heritabilities of 61.4 and 38.8%, respectively, on a single-plant basis. A test for midparent heterosis also showed significance (P<0.05). Genetic control of SFM was quantitative in nature, and highly dominant. The F₁ and F₂ generations had FMP of 47.2 and 49.5 days, respectively. F₁, F₂, and backcross generations all differed in number of fruits per plant, giving broad- and narrow-sense heritabilities of 69.73 and 55.67%, respectively. With a mean per fruit weight of 150.1 g Petomech recorded the highest fruit weight, while Small Fry recorded the lightest fruit weight of 81.4 g. Estimated broad-and narrow sense heritability for fruit weight was 71.76 and 41.68%, respectively. There was a significant difference between Small Fry and Petomech, as well as the BC₁ and BC₂ in terms of fruit size. The highest heterotic effect was found in number of fruits per plant (27.6%) over mid-parent. The highest yield was recorded by Petomech (18.9 t ha^-1), while Small Fry recorded the lowest value of (14.3 t ha^-1).

Keywords: Genetics, heterosis, heritability, Lycopersicon esculentum