QTL mapping for the paste viscosity characteristics in rice (Oryza sativa L.)

In order to understand the genetic basis of the paste viscosity characteris tics (RVA profile, which is tested on the Rapid Visco Analyser) of the rice grain, we mapped QTLs for RVA profile parameters using a DH population der ived from a cross between an indica variety, Zai-Ye-Qing 8 (ZYQ8), and a ja ponica variety, Jing-Xi 17 (JX17). Evidence of genotype-by-environment inte raction was found by comparing the mapped QTLs between two locations, Haina n (HN) and Hangzhou (HZ). A total of 20 QTLs for six parameters of the RVA profiles were identified at least one location. Only the waxy locus (wx) lo cated on chromosome 6 was detected significantly at both environments for f ive traits, i.e. hot paste viscosity (HPV), cool paste viscosity (CPV), bre akdown viscosity (BDV), consistency viscosity (CSV) and setback viscosity ( SBV). This locus explained 19.5%-63.7% of the total variations at both envi ronments, suggesting that the RVA profiles were mainly controlled by the wx gene. HPV, CPV, BDV, CSV and SBV were also controlled by other QTLs whose effects on the respective parameter were detected only in one environment, while for the peak viscosity (PKV), only 2 QTLs, 1 at HN,the other at KZ, w ere identified. These results indicate that RVA profiles are obviously affe cted by environment.