QTL analysis of leaf photosynthetic rate and related physiological traits in rice (Oryza sativa L.)

Photosynthesis is the primary source of dry matter production and grain yield in rice. Study on genetics of photosynthesis and related physiological characters is very important to rice physiological breeding. In this study, a double haploid (DH) population derived from anther culture of ZYQ8/JX17, a typical indica and japonica hybrid was used as genetic material. Net photosynthetic rate, chlorophyll content, stomatal resistance and transpiration rate of the parents and DH lines were investigated in flourishing tillering period. The quantitative trait loci (QTLs) for each trait were analyzed based on the constructed molecular linkage map of this population. A total of 8 QTLs for photosynthesis and related physiological characters were detected. Two putative QTLs for net photosynthetic rate (qNPR-4 and qNPR-6) were mapped on chromosome 4 and 6, respectively. Three QTLs (qCC-1, qCC-3 and qCC-8) for chlorophyll content were detected on chromosome 1, 3 and 8, respectively. One QTL for stomatal resistance (qSR-4) was identified on chromosome 4. Two QTLs for transpiration rate (qTR-4 and qTR-7) were detected on chromosome 4 and 7, respectively. These QTLs should accelerate the process of breeding new rice varieties with higher photosynthetic capacity and higher yield.