SEED AND SEEDLINGS PHYSICAL CHARACTERISTICS AND SEEDS GERMINATION OF WILD AND DOMESTICATED COMMON BEAN (Phaseolus vulgaris L.) AND THEIR PROGENY

The source of the tolerance to biotic and abiotic factors of currently consumed common bean (Phaseolus vulgaris L.) cultivars could be found in their wild counterparts. But they and their progeny should first be characterized. The aim of this study was to evaluate the physical characteristics of the seed, seed germination and seedling emergence of wild and domesticated common bean (P vulgaris L.) and their progeny. The hypothesis was that one or more characteristics of the progeny are outstanding compared to cultivars. In random samples from three wild accessions (Typical Durango, Chihuahua and S13), two cultivars (Bayo Mecentral and Negro Tacana) and five progenies (3.3, 11.1, 51b, 53b, and 118b) of the wild S13 and cv. Negro Tacana: biomass, width, thickness, length, proportion of cotyledons, embryonic axis and seed coat, of the seeds, and percentage of seed germination and seedling emergence were evaluated. The experimental design was completely randomized, ten treatments (three wild accessions, two cultivars, and five progeny derived from crossing the cultivar Negro Tacana and wild S13) with 100 replicates, each seed being an experimental unit. The results were analyzed with size frequency curves, ANOVA and multiple comparisons of means with the Tukey test (p <= 0.05). Seed biomass (67 to 124 mg), width (4.36 to 5.72 mm), length (2.65 to 4.92 mm) and thickness (6.81 to 8.47 mm) showed a gradient from wild variants and progeny to domesticated variants. Wild seeds and progeny had higher proportion of embryonic axis (1.74% and 2.12%) than domesticated (1.34 %). Seed germination and seedling emergence did not differ between the variants. Only some characteristics of the progeny, as the proportion of cotyledons and embryonic axis in seeds, were higher than in the cultivars.