Evaluation of F1 Hybrid Tomato Cultivars for Earliness, Fruit Size, and Yield Using Diallel Analysis1

Abstract

Abstract Twelve cultivars and one breeding line of tomatoes, (Lycopersicon esculentum Mill.) which varied in maturity from early to late cultivars, were crossed in a diallel to estimate general and specific combining ability for earliness, fruit size, and yield using Griffing's method II, model II. General combining ability mean squares for earliness at 3 stages expressed as growing degree days (GDD) (10–32°C); and for number of days were larger than specific combining ability mean squares except for the index of first flowering stage to first fruit set. Days from seeding to first flowering and of first fruit set to first ripe fruit were positively correlated with each other and with total earliness. However, days from first flowering to first fruit set was not correlated either with the period from first fruit set to first ripe fruit or with total earliness. Fruit sizes, measured at the 3 different times were positively correlated with each other and with overall average size. A positive correlation resulted between the September 1st and October 1st yields and total yield. There was no significant correlation between fruit size and yield. General and specific combining ability mean squares were estimated on August 1st, September 1st, and October 1st for fruit size and yield. Broad sense heritability estimates were high and narrow sense heritability estimates were low, for both fruit size and yield.