Novel Genetic Variation in Common Bean from the Iberian Peninsula

Abstract

The common bean (Phaseolus vulgaris L.) was introduced from the Americas into the Iberian Peninsula approximately 500 yr ago. Considerable genetic variation for morphological traits, allozymes, phaseolin protein, and reaction to bacterial, fungal, and viral diseases exist in the germplasm. Our objective was to identify novel genetic variation in a collection from the Iberian Peninsula. Three hundred forty-seven accessions were characterized for seven morphological traits, phaseolin protein, and eight allozymes at the Misión Biológica de Galicia, Pontevedra, Spain, between 1998 and 2005. All 347 accessions were cultivated common bean of which 102 were typical Andean and 52 were Middle American, corresponding to the two major gene pools. Nine groups could be identified among the remaining 193 accessions. Twenty-eight accessions with the Middle American phaseolin formed four groups: 13 large (41–55 g 100 seed weight–1), five very large (56–70 g 100 seed weight–1), two extra-large (>70 g 100 seed weight–1), and eight inter–gene pool recombinants. The latter had one or more morphological and allozyme traits of the Andean gene pool. Similarly, 165 accessions with the Andean phaseolin formed five groups: 19 extra-large, 30 very large, 80 medium (25–40 g 100 seed weight–1), 10 small (<25 g 100 seed weight–1), and 26 inter–gene pool recombinants. Seed yield potential and physiological, breeding, genetics, and evolutionary significance of these novel forms and recombinants need to be determined.