Starch RVA profile parameters of rice are mainly controlled by Wx gene

Quantitative trait locus (QTLs) mapping for rapid visco: analyser (RVA) pro file parameters has been carried out by using a double haploid (DH) populat ion derived from a cross between indica variety Zhai-Ye-Qing 8 and japonica variety Jing-Xi 17 and its genetic linkage map. The results indicate that the segregation of the RVA profiles:is continually distributed among the DH lines, and some DH lines show transgressive segregation for all the parame ters, A major QTL, Wavy (Wx) gene on chromosome 6 which controls the amylos e synthesis, has been detected significantly for 5 traits: hot paste viscos ity (HPV), cool paste viscosity (CPV), breakdown viscosity (BDV), consisten cy viscosity (CSV) and setback viscosity (SBV), Therefore, the RVA profile parameters are mainly controlled by Wx gene. Other 3 and 2 QTLs have also b een identified for BDV and SBV, respectively, and two of them share the sam e region on chromosomes 1 and 5, However, the peak viscosity (PKV) is contr olled by a minor QTL on chromosome 12, qPKV-12.