MULTIVARIATE-ANALYSIS OF VARIATION AMONG SOLANUM-COMMERSONII (-TUBEROSUM SOMATIC HYBRIDS WITH DIFFERENT PLOIDY LEVELS() SOLANUM)

In order to integrate the outcomes of interspecific somatic fusion exp eriments in breeding schemes, it is important to understand factors in volved in the variability observed among regenerated plants. With such a purpose in mind, a population of Solanum commersonii (+) S. tuberos um somatic hybrids was examined by means of discriminant and cluster a nalyses. Data were collected on 56 hybrids with different ploidies and on the two diploid parents grown in a greenhouse. The ploidy group wa s used as discrimination criterion. Three significant canonical variab les were extracted by discriminant analysis; they were mainly correlat ed with the number of leaflets and stems, degree of flowering, plant h eight, and leaf length. After cluster analysis carried out with the si gnificant canonical variables, parental and hybrid clones were grouped in 7 clusters. In the canonical space of reduced dimensions, patterns of morphological variation depended mainly on ploidy level and non-ad ditive gene interactions. Hybrids were in general more similar to the cultivated than to the wild species, suggesting a good chance of fast introgression of useful traits from S. commersonii into the S. tuberos um genetic background.