Distribution of microsatellite alleles linked to Rht8 dwarfing gene in wheat

A wheat inicrosatellite locus, Xgwm 261, whose 192-bp allele closely linked to the dwarfing gene Rht8, on chromosome 2D, was used to screen 71 wheat cultivars from 13 countries to assess the variation at this locus. Screening of this wheat collection showed that a 165-bp allele and a 174-bp allele were the most frequent. None of the New Zealand cultivars possessed a 192-bp allele specific to Rht8, while only one cultivar from the US produced this important allele. The frequency of a 192-bp allele among these wheat cultivars was 5.63%. The highest allele frequency was observed for a 174-bp fragment (52.11%) followed by a 165-bp fragment (26.76%). The only durum wheat 'Cham 1', did not show any amplification due to the absence of D genome. Four new novel alleles, 180-bp, 198-bp, 200-bp and 204-bp present in the US and New Zealand wheat cultivars are reported.