Abstract
Studies were carried out on the morphological characterization and genetic diversity of 150
accessions of hyacinth bean collected from Bangladesh and 16 other countries. Experiments
were also conducted to develop a reproducible regeneration protocol for hyacinth bean. The
accessions showed colour variations in hypocotyl, epicotyl, main stem, leaf and leaf vein.
Variations were also observed in terminal leaflet shape, plant growth pattern, edible pod
colour, shape and curvature, seed colour, shape and size among the 150 accessions. Low to
high phenotypic diversity index (0.14 to 0.99) was found among the characters. Variations
were observed in leaf length and width, days to flowering, length of rachis and peduncle,
number of flowering nodes, node density, number of pods per rachis, edible pod length, width
and weight, number of pods per plant and seeds per pod, seed length and width and hundred
seed weight (5.30 to 43.87% phenotypic co-efficient of variation). All the 150 accessions
from 17 countries were grouped into ten clusters using D2 values. Inter-cluster distance
ranged from 1.45 to 12.14. No relationship was found between geographic origin and genetic
diversity. Molecular characterization in 65 accessions was conducted using 13 Simple
Sequence Repeat markers (SSR). A total of 47 polymorphic alleles were counted. Two to five
alleles per primer were detected with an average of 3.62. Polymorphism information content
values ranged from 0.21 to 0.72 with a mean of 0.53. Average gene diversity was 0.59
ranging from 0.24 to 0.76. Phylogenetic analysis classified the 65 accessions into 8 groups.
Comparatively greater diversity was exhibited among the accessions of Bangladesh than
those from abroad. In vitro regeneration potential of three accessions was examined in MS
and B5 media. Shoot development was better in immature embryo cultured on MS medium
than on other media compositions like half strength MS, MS with 15%CW, half and full
strength of B5, and also MS medium supplemented with NAA (0, 0.1, 0.5 mg/l) with BAP
(0.5, 1.0, 2.5 mg/l). Shoot tip culture was superior in medium supplemented with 0.1 mg/l
BAP to the remaining treatments. Shoot development through node culture was better in MS
medium than that containing ВAР (0.5, 1.0, 2.5 mg/l) with NAA (0, 0.1 mg/l) while
cotyledonary node culture was superior in MS medium with 0.2 mg/l BAP, to MS and B5
media and also MS medium with 0.1 mg/l BAP. The accession BD-8001 performed better in
shoot development through immature embryo, shoot tip and cotyledonary node culture while
BD-122 performed better in node culture. Root development was superior in MS from
immature embryo culture while MS containing 0.1 mg/l IBA was the superior from in vitro
developed shoot. The Accession BD-8001 performed better in root development than the
remaining two accessions. The combination of 0.5 mg/l BAP and 0.5 mg/l Kn with BD-122
as well as 3.0 mg/l 2,4-D and 1.0 mg/l BAP with BD-8001 in MS was superior for callus
development through immature cotyledon culture. The breeders can select the promising
accessions BD-122, BD-8770, BD-8785, BD-9446 and BD-9457 for hybridization program
and claim sovereign right from SSR findings. Immature embryo explants of accession BD8001 cultured on MS medium without growth regulators performed the best for regeneration.
The protocol developed has the applicability in capturing the hyacinth bean diversity through
collection of immature edible pod directly from the market.