CHARACTERIZATION AND CLASSIFICATION OF DIFFERENT GENOTYPES IN A POPULATION OF CUCUMIS-MELO BASED ON THEIR ABILITY TO REGENERATE SHOOTS FROMLEAF EXPLANTS

Variability of the in vitro organogenic response from leaf explants of a seed population of Cucumis melo L. cv. Cantaloupe Charentais was an alyzed to detect genotypic variability among individual seeds for shoo t regeneration. Variation in shoot regeneration frequency among plants from different seeds was compared to that found among clonal replicas of each original plant. Clonal propagation was performed using in vit ro culture of apical and axillary buds of axenic plants to avoid somac lonal variation. Results demonstrate the existence of highly significa nt differences among plants from the seed population. Regeneration fre quency of leaf explants derived from clonally propagated sets of a sin gle plant can be described by a binomial distribution for each origina l plant coming from one seed. Using data from stochastic simulation, w e studied the accuracy of different analyses to detect the presence of genotypic heterogeneity in a population. These analyses, together wit h our experimental design, allowed the separation of genotypes differi ng up to 5% in their regeneration ability. Results of this work should allow researchers to hypothesize about those genotypes that differ wi thin a population and their frequency.