DEVELOPMENT OF MAPPING POPULATION AND IDENTIFICATION OF QTLS FOR HIGH ZINC CONTENT IN PIGEONPEA [Cajanus cajan (L.) Millsp.]
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Date
2016-04-23
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UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU
Abstract
Zinc plays key roles in plants and human health regulating several major
physiological and biological processes. It has emerged as the most widespread
micronutrient deficiency in soils and crops worldwide, resulting in severe yield losses
and deterioration in nutritional quality, ultimately leading to human zinc deficiency. The
short term interventions to curb human zinc deficiency are mineral supplementation,
dietary diversification and food fortification but they are not economically viable in the
long run. So, biofortification through genetic or agronomic approaches may be a long
lasting solution to cater the needs of both the rural and urban population. In this direction,
30 high and low zinc genotypes selected out of 217 germplasm lines outsourced from
ICRISAT were genotyped to analyze their genetic diversity using 50 SSR markers. Cross
were conducted between selected lines. Of the crosses, the cross ICP6443 X ICP10960
was used to develop mapping population segregating for seed Zn content and
subsequently used for phenotyping, linkage mapping and QTL analysis. Significant
phenotypic variability was noticed for the seed zinc and other traits in the population. The
polymorphic information of 151 SSR markers were used to construct linkage map.
Multipoint linkage analysis resulted in linkage map of 62 markers into 10 linkage groups
with a total map length of 1942.8 cM. QTLs for seed zinc, leaf zinc and yield traits were
identified using linkage mapping. Several pleiotropic markers were identified for
different traits in QTL analysis. Single marker analysis and composite interval mapping
resulted in discovery of common markers (AHSSR93, AHSSR118 and ASSR280) for
seed zinc content. The study lead to discovery of several transgressive segregates with
high seed zinc content, serving as potential genetic resources. An important genic marker
bZIP transcription factor (ASSR20) speculated to regulate zinc deficiency response is
found to be linked to seed zinc content.
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