Abstract:

The quantitative trait loci (QTLs) for root traits, such as root number, the longest root length, the diameter of longest root, root dry weight, ratio of root to seedling at the seedling stage in rice under 12℃ cold water irrigation and natural condition was identified by using F_2∶3 population including 200 individuals and lines derived from a cross of indica and japonica “Milyang23/Jileng1” with microsatellite markers. All of root traits at the seedling stage showed a continuous distribution in F₃ lines, which were quantitative traits controlled by many genes. Seventeen QTLs on chromosome 1, 2, 6, 11 and 12, which associated with root traits at the seedling stage under cold water irrigation were detected, which explained the range of the observed phenotypic variance from 5.8% to 15.2%. Among them, qCDR2 and qCDR11 located on RM263-RM6 of chromosome 2 and RM21-RM206 of chromosome 11, respectively, which associated with the diameter of longest root could account for 15.0% and 15.2% of observed phenotypic variation, respectively. qCRWT2 and qCRWT11 located on RM262-RM263 of chromosome 2 and RM229-RM21 of chromosome 11, respectively, which associated with root dry weight could account for 10.6% and 12.2% of observed phenotypic variation, respectively. These gene action was partional dominance or dominance or over dominance.

Key words: Rice, Root, Cold water irrigation, Microsatellite marker, QTLs