STUDY OF GENETIC DIVERSITY OF NATIVE AVOCADO IN NUEVO LEÓN, MÉXICO

Abstract

The State of Nuevo León in México is the center of origin of Persea americana Mill. spp. drymifolia, as evidenced by the remains of fruits found in caves of Nuevo Leon’s Sierra Madre Oriental mountains. Within the state, native avocado plants have been found in the wild with different characteristics to the current varieties cultivated in family orchards. This diversity represents a valuable source of genes and genetic combinations that can be used in Persea breeding programs. Because this genetic diversity has not been studied, an analysis of 42 native avocado samples on the basis of the fruit traits: weight, length and diameter of fruit; weight, length and diameter of seed and length and diameter of the seed cavity; and relations between length/diameter of fruit and weight seed/weight fruit was carried out. Only seed weight, fruit weight, length of seed cavity and fruit length were useful for classification of the species. The results made clear that the classification based on morphological fruits traits did not represent the variability. Characterization by molecular markers offers the possibility to evaluate directly the genetic diversity. AFLP analysis allowed to distinguish five different varieties and the separation of varieties with the same local name, thus demonstrating genetic differences within varieties of the Mexican race. When the molecular data were analyzed together with the morphological data, eleven varieties were differentiated and the separation of varieties with the same local name was possible again. The utility of AFLP in the analysis of genetic diversity between varieties of avocados of the Mexican race has been demonstrated with these results