Identification of allelic variants of Xgwm261 locus for Rht8 dwarfing gene in Pakistani wheat genetic resource

摘要

Semi dwarfing wheat gene ( Rht8 ) is among the important Green Revolution genes to increase productivity by modifying plant stature. Plant height is among one of the important constituent of plant architecture that determines the stability, harvest index and yield of crop plants. Strong linkage of Xgwm261, a wheat microsatellite marker with the dwarfing gene ( Rht8) resulting in reduced height makes it well known marker among the breeders. Using this functional SSR marker, Pakistani wheat varieties and land races were analyzed to access the allelic distribution/ variation at microsatellite Xgwm261 locus. The 165-bp and 174-bp alleles of Xgwm261 were most frequent (38 and 24% respectively) among studied genotypes. A 192-bp diagnostic allele of Rht8 gene was not detected in tested germplasm. Here we also report novel WMS 261 variants of 182-bp, 188-bp, 196-bp and over 200-bp (205 and 215-bp) in some tested genotypes. For this microsatellite Xgwm261 locus the value of polymorphic information content ( PIC ) was 0.55. Conclusively, a high level of diversity for this locus was observed. Seven different microsatellite alleles were detected and a strong linkage of these variants at the Rht8 locus if identified will provide a better understanding for gene to environment interaction for designing appropriate marker assisted selection ( MAS ) for high yielder wheat cultivars. Observed higher frequency of major allele (165-bp) could possibly be due to usage of CIMMYT wheat materials in Pakistani breeding programs. Selection of appropriate alleles will be useful in the varietal improvements breeding programs.