Molecular mapping and marker association studies in diploid cotton (gossypium spp.)
Loading...
Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UAS Dharwad
Abstract
Cotton is one of the most important commercial crops grown in India. It is the world’s
leading natural fibre crop and is the cornerstone of textile industries worldwide. Inspite of
several competitions from synthetic fibres, cotton continues to enjoy a place of prime
importance in textile industry. As diploid cottons are well suited to rainfed ecosystem and can
fulfil the increasing demand for medium staple nature of fibres, it still necessitates having
diploid cottons with improved fibre quality. The present investigation was undertaken to
construct the genetic map and to identify QTLs for important yield contributing and fibre
quality traits using 50 polymorphic SSR markers in 154 recombinant inbred lines (RILs)
derived from the cross between G. herbaceum variety Jayadhar and G. arboreum variety
DLSa17.
Genetic variability components revealed higher magnitude of variation for most of the
traits. This was evidenced by high range and mean performance for different traits in RILs.
Per se performance of RILs indicated the improvement over parents for various productivity
and fibre quality traits. Association among different traits under study revealed, significant
association of seed cotton yield with ginning out turn and lint yield. Fibre length exhibited
highly significant positive correlation with fibre strength (0.41) and fibre elongation (0.48).
Genetic linkage map was constructed with 50 polymorphic markers. The total map length
was 4033.95cM with average distance of 80.68cM between the markers. Out of 15 QTLs
detected, seven QTLs were for seed cotton yield. The chromosome 6 harboured QTLs for
more than one trait viz., ginning out turn, seed cotton yield, lint yield and uniformity ratio.
Three QTLs each corresponding to seed cotton yield, lint yield and uniformity ratio were
present between NAU2964 and MUSB1248. The construction of ‘A’ genome diploid map
with SSR markers, can serve as a model for the advancement of cotton genetics and
genomics. Adding additional markers to the existing map to saturate the map will assist in
future map based cloning efforts and fine mapping studies.