ANALYSIS OF PEACH GERMPLASM IN MEXICO

A wide range of peach [Prunus persica (L.) Batsch] germplasm was colle cted from the most important peach growing regions in Mexico and some Latin American countries, as well as from breeding programs in the Uni ted States, Europe, and South Africa. Budded trees, seedlings derived from selfing cultivars and selections, and seed samples from various g rowing regions were propagated and planted in central Mexico. Twenty e ight morphological or phenological variables were recorded on 52 acces sions representing different geographic regions. The highest degree of variability was observed for traits related to bud density and distri bution, and to phenological variables associated with temperature requ irements such as budbreak and harvest seasons, leaf fall, fruit develo pment, and seed stratification period. Principal component analysis (P CA) integrated groups of phenotypes based mainly on growth habit, shoo t diameter, bud and leaf size, as well as resistance to powdery mildew , rust, and frost. PCA provides support for the development of objecti ves and breeding strategies in the search for germplasm and cultivars for nontraditional peach growing regions.