MORPHOLOGICAL DIVERSITY OF CULTIVATED SQUASH FROM CENTRAL-EASTERN YUCATÁN, MÉXICO

Abstract

Current morphological and genetic variability of squash in the “milpa” system at Yucatan has been scarcely studied. In this study 36 squash landraces of the C. argyrosperma and C. moschata species, cultivated at the central-western region of Yucatán, were characterized in association with a local maize variety (Zea mays L.) of the “Xnuc nal” type grown at 40 000 plant/ha, in Yaxcabá, Yucatán, during 2003. Landraces were planted following a lattice design in plots with 8 plants (72 m² ), and a 3 m distance between plants; the experiment was carried out based on farmer’s local practices. Qualitative (11) and quantitative (14) traits of plant, fruit and seed were analyzed with principal components, correspondence, and cluster multivariate methods. Both species split clearly into two large groups based on morphological traits; within each species subgroups with differential characteristics were formed. Seed length and width, 100 seeds weight, days to female flowering, fleshy thickness, and fruit length and width explained most of the quantitative variation; leaf shape, fruit longitudinal shape, and colour intensity of leaf spots explained most of the qualitative variation. C. moschata landraces had small seeds with thin margin, growth season from intermediate to late, different fruit sizes and forms, thick flesh and abundant stem pubescence. In contrast, C. argyrosperma landraces were early flowering plants which produced larger and heavier seeds with thick margin, small to medium round fruits, and scarce stem pubescence.