Cytogenetic and morphological characterization of lima bean germplasm from the Brazilian Northeast region with a focus on genetic resource conservation

Abstract

In Brazil, lima bean is mainly grown in the Northeast region, where it is widely consumed and is of major economic importance. We evaluated different Phaseolus lunatus accessions from the Northeast of Brazil using agromorphological markers and CMA/DAPI fluorochrome banding techniques. All the accessions showed CMA⁺ blocks of pericentromeric constitutive heterochromatin (CH). At least one pair of CMA⁺⁺ terminal marks corresponds to the nucleolus organizer region (NORs). Characterization of the seeds suggests that the two Andean and Mesoamerican Phaseolus cultigroups are represented in the Brazilian germplasm analyzed. Most of them belong to the "Big Lima" group. Characterization studies of lima bean germplasm are important for increasing knowledge of the diversity and variability of the species and for generating useful information for breeding and conservation of this economically important legume.

Keywords:
Phaseolus lunatus; karyotype analysis; CMA and DAPI fluorochromes; heterochromatin; seed characterization