A BIOCHEMICAL TRAIT HELPS TO RECOGNIZE PHASEOLUS PARVIFOLIUS FREYTAG IN THE GENE POOL OF TEPARY BEAN

摘要

The section of Phaseolus currently including the tepary bean, i.e. the Acutifolii, consists of two species: Phaseolus acutifolius A. Gray (with three varieties: var. acutifolius, var. latifolius and var. tenuifolius) and P. parvifolius Freytag (Freytag & Debouck 2002). Schinkel & Gepts (1989) could not separate these varieties by nine allozyme assays. Garvin & Weeden (1994a) reported limited polymorphism for aconitase, apparently with no relationship with foliar attributes. Jaaska (1996) found a unique electromorph for three out of six accessions of var. tenuifolius, now classified in CIAT as 'parvifolius'. In a study of 91 accessions with ten enzyme systems, Florez (1996) found that the allele Aat-295 uniquely separates the twelve "parvifolius" materials from the rest of wild teparies. Zink & Nagl (1998) reported a minor difference in banding pattern of microsatellites between P. parvifolius and accessions of P. acutifolius. Munoz et al. (2002) found in a diversity study with help of AFLPs that P.parvifolius forms a group separating from other wild teparies at the level of separation of common bean genepools. The purpose of this study was to find a biochemical marker ("diagnostic isoenzyme") for the recognition of either one of the varieties oftepary bean.