[QTL mapping of the root traits in rice seedling]

Drought resistance is one of the most important traits in rice abiotic study. The report here analyzed several major root traits affecting drought resistance expression with the double haploid population (DH) from ZYQ8 (indica)/JX17 (japonica) containing 127 lines. After 10 days solution culturing, three rice root traits, Maximum Root Length (MRL), Dry Root Weight (DRW) and Root/Shoot Ratio of Dry Weight (RSR), were revealed existing significant difference among the DH lines. Using the constructed molecular linkage map from this segregating population, the QTL mapping was conducted among these three root parameters. MRL, DRW, and RSR were found being controlled by 2/1/2 QTLs respectively in JX17, 2/0/1 QTLs respectively in ZYQ8. Phenotype variance could be explained by 16.4% and 17.0% for MRL, 16.4% for DRW, 10.4% and 19.9% for RSR in JX17, 19.6% and 13.0% for MRL, 13.2% for RSR in ZYQ8. All these QTLs identified were distributed on rice chromosome 2, 3, 4, 5, 6, 9 and 10. Comparing with the other mapping results, one QTL for each trait (L169-CT106A for MRL, G45-G1314A for DRW, G62-G144 for RSR) was identical with the results reported previously.