Quantitative trait loci (qtl) analysis of genomic regions associated with yield component traits in a recombinant inbred line population of rice (oryza sativa l.)

Six environments across three locations were used to evaluate 144 lines of a rice recombinant inbred line (RIL) population derived from a cross of Kogoni91-1 and IR64. Five traits including days to 50% flowering, plant height, number of grains per panicle, thousand kernels weight and grain yield were recorded. Further, this population was genotyped with 228 single nucleotide polymorphism markers (SNP). Significant differences (P < 0.001) were recorded among genotypes for all traits except for GY. Therefore, QTL analyses were performed on the combined phenotype data of the four traits by excluding grain yield. Composite interval mapping (CIM) analysis detected 12 QTLs. Among these, six (qPH8, qPH3, qPH2, qTKW2, qNGP4 and qNGP8) are novel and reported for the first time and two are major QTLs, qPH8 (R2=16.8) and qTKW2 (R2=16.6). These novel QTLs will be suitable for fine mapping and map-based cloning studies. The remaining six had occurrences corresponding to QTLs reported in mapping populations previously. Pyramiding the identified major QTLs could be highly helpful for breeding programs to increase rice grain yield potential. The study confirms that the RIL population used constitutes a prominent source of variability for traits of complex inheritance.