Evaluation of Some Field-Grown Tomato Hybrids Using Multivariate Statistical Methods for Breeding Programs

Tomato (Solanum lycopersicum L.) is one of the important horticultural crop species world-wide. Identifying superior genotypes with a high yield and acceptable fruit quality can pave the way for breeding programs. In order to identify the best tomato cultivars for some of fruit quality and yield related traits, a 3-replicate experiment with 20 commercial tomato hybrids in randomized complete block design was conducted in research field of Tarbiat Modares University in Tehran, in 2017. The examined traits included number of days to flowering, number of days to first fruit-set, plant height, number of primary branches, number of primary clusters, number of fruits per plant, fruit yield per plant, leaf chlorophyll index, fruit juice acidity, fruit electrical conductivity, water salinity, total dissolved solids, percentage of brix and fruit lycopene content. Hybrids were compared by two methods of the heatmap clustering and the analytical hierarchy process as a multivariate indicator. Among the 14 tested traits, four traits including number of days to flowering, leaf chlorophyll index, water salinity, and total dissolved solids, indicated low heritability and genotypic/phenotypic correlation with fruit yield and hence were denied for multivariate analysis. Hybrids Hypeel 108 and Queenty were superior to the other hybrids in fruit lycopene content and fruit yield, respectively, and both hybrids had an acceptable fruit juice acidity for processing in the food industry. Hybrids Queenty, Adora, Berlina, and Hypeel 108 indicated the highest AHP values and the highest genetic distances. Thus, they were found to be the most suitable genotypes for cultivating in areas with similar climatic conditions and formation of next breeding generation. These hybrids were superior to other hybrids, not only in fruit yield but also in a great majority of the traits.