AFLPs and morphological diversity of Phaseolus lunatus L. in Cuban home gardens: approaches to recovering the lost ex situ collection

Abstract

The genetic diversity of 76 accessions of lima bean (Phaseolus lunatus L.), collected mostly from home gardens, was assessed with AFLPs and seed descriptors to evaluate the potential for recovering a lost ex situ collection in Cuba. The sample contained 60 accessions collected from 25 home gardens in the three main geographical regions of Cuba and represented the three cultivated types found on the island. Four more accessions were part of the former ex situ collection and the remaining 12 accessions were selected from the world bean collection held at the International Center for Tropical Agriculture. Some morphological measurements discriminated among cultivated types. The analysis of 62 polymorphic bands obtained with two AFLP primer combinations indicated that the three cultivated bean types were comparable in terms of molecular diversity and that no pattern of variation was associated with geographical distribution. However, a multiple correspondence analysis with the same molecular data detected different genetic groups. Three of these groups included all the cultivated accessions collected from home gardens, but could not be explained by the seed descriptors. The results therefore suggest that a scientifically sound collecting strategy to recover the former Cuban ex situ gene bank should consider combining geographical, morphological, and molecular data. The findings also suggest that any proposed methodologies should be considered before developing a conservation strategy based on an ex situ or combined ex situ and in situ approaches.

Qualidade física e fisiológica de sementes de Phaseolus lunatus L.

“…A diversidade encontrada no presente estudo, em relação à morfologia das sementes, foi relatada por Castiñeiras et al (2007), que avaliaram 76 acessos de P. lunatus, e classificaram o feijão-fava em oito grupos distintos quanto ao tamanho, comprimento, largura e circunferência das sementes.…”

“…Os marcadores moleculares permitiram identificar os acessos em três grupos de feijão-fava cultivados (Sieva, Sieva/Papa e Papa) e suas origens geográficas (norte, centro e sul), já os morfológicos permitiram separar apenas os grupos cultivados, devido à característica fenotípica ser grandemente influenciada pelo fator ambiental e grande pressão de seleção exercida pelos agricultores (Castiñeiras et al, 2007). Guimarães et al (2007) separaram 22 acessos oriundos dos Estados do Ceará, Paraíba e Pernambuco em dois grupos diferentes utilizando marcadores RAPD, já com a utilização de marcadores morfológicos, como a massa de 100 sementes não foi possível separar os acessos devido a influência ambiental e a existência de troca de sementes entre agricultores geograficamente próximos.…”

Genetic erosion and in situ conservation of Lima bean (Phaseolus lunatus L.) landraces in its Mesoamerican diversity center

“…This difference may be due to the low representativity of the plant material used by Nienhuis et al (1995). Castiñeiras et al (2007), using AFLP molecular markers, analyzed the genetic diversity of Potato-Sieva landraces planted in the Cuban home gardens. They reported a genetic diversity (h = 0.119) similar to the one reported by Nienhuis et al (1995).…”

Genetic structure of Lima bean (Phaseolus lunatus L.) landraces grown in the Mayan area

“…Lioi et al (1998) reported H E = 0.13 for 60 cultivated accessions that included both Mesoamerican and Andean landraces. Castiñeiras et al (2007), using AFLP markers, reported H T = 0.13 for 65 cultivated accessions from Cuba. Montero-Rojas et al (2013) reported H E = 0.337 and H O = 0.403 for 50 landraces collected directly from Haiti, Puerto Rico and the Dominican Republic.…”