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GENETIC STUDIES AND IDENTIFICATION OF MOLECULAR MARKERS FOR SEED COAT PERMEABILITY IN SOYBEAN

KrishiKosh

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Title GENETIC STUDIES AND IDENTIFICATION OF MOLECULAR MARKERS FOR SEED COAT PERMEABILITY IN SOYBEAN
 
Creator SUBHASH CHANDRA
 
Contributor Akshay Talukdar
 
Subject null
 
Description t-9786
Soybean (Glycine max L. Merrill) is an important source of quality oil and protein in
India. Maintaining prescribed level of soybean seed germination in ambient storage is
critical in humid environment. Seed coat permeability is an important physical property
that influences electrolyte leaching and seed longevity. In the present study, seeds of 125
soybean genotypes including 105 genotypes of cultivated type (Glycine max), 19
accessions of annual wild type (Glycine soja) and one accession of perennial wild type
Glycine tomentella, were screened for seed coat permeability after 6hrs (SCPH) and
7days (SCPD) of imbibition. All the cultivated genotypes had permeable seed coat both
under SCPH and SCPD. Seed coat of G. soja accession DC2008-1 and the G. tomentella
accession were impermeable under SCPH but semi-permeable under SCPD. Based on
germination potential after two years of ambient storage, 22 genotypes of cultivated type
were identified as good storers. Out of 19 wild type accessions, 14 had more than 70%
germination after three years of ambient storage. The 100-seed weight and seed coat
permeability were found to have negative correlation with seed germination. Electrical
conductance from seed leachates was found as good indicator for seed longevity in
soybean. Soft -seeded, poor storers genotypes showed more rate of imbibition than hardseeded,
good storing genotypes. Scanning Electron Microscopy (SEM) revealed presence
of cracks and minute pores on cuticle of seed coat surface of soft seeded genotypes. The
hourglass cells were uniform in shape and distribution in the good-storing genotypes
compared to those in the poor-storing genotypes. Inheritance of seed coat impermeability
in cross combinations PI424079 (hard seeded) X JS335 (soft seeded) and cross PI366120
(hard seeded) X JS335 (soft seeded) was dominant over seed coat permeability and was
controlled by one major gene (QTL) in 124 and 93 F2 plants of the respective crosses.
Involvement of minor genes was also indicated. A 204 RILs developed from DC2008-1
(G. soja) and DS9712 (G. max.) was surveyed with 400 SSR markers and found 218
markers as polymorphic (54.56%) between the parental lines. The linkage map developed
by using 207 SSR markers was 1851.55cM in length with an average marker distance of
8.94 cM. Seven QTL affecting seed coat permeability after 6 hours of soaking (SCPH)
were mapped on chromosome Nos. 2, 5, 12, 13 and 16 in the seeds stored for 1-3 years
(2013 to 2015). Five QTL affecting seed coat permeability after 7 days of imbibition
(SCPD) were mapped on chromosome Nos. 2,9,10 and 20 in the seeds stored for 1-3
years (2013 to 2015). Phenotypic variation explained (PVE) by each QTL ranged from
5.96 to 39.67% and 7.70 to 26.64% for SCPH and SCPD, respectively. Two major stable
QTL viz., qSCPH2-1 and qSCPH2-2, which are located in tandem on Chr.2, together
explained 62.92% and 43.09% phenotypic variance on the seeds of two years and one
year of ambient storage. One major and five minor QTLs identified in this study for both
types of seed coat permeability was novel. Three SSR markers viz., Satt703, Sat_202 and
Satt274 were validated in an independent F2 population. It explained about 43% of
phenotypic variance for seed coat permeability in the validation (F2) population. A set of
RILs was identified that had permeable seeds with >70% germination even after three
years of ambient storage. The QTL and markers identified in this study will pave the way
for developing genotypes with enhanced permeability and viability through molecular
breeding.
 
Date 2018-10-09T09:37:26Z
2018-10-09T09:37:26Z
2017
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/5810077883
 
Language en_US
 
Format application/pdf
 
Publisher DIVISION OF GENETICS ICAR - INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI-