Mapping of QTL associated with root and related traits in population of rice (Oryza sativa L.)

Mapping of QTL associated with root and related traits was undertaken in a DH population of indica x indica cross (CT9993/IR62266). Totally 18 QTL, spread across chromosomes were detected at threshold LaD of 2.20. The alleles of IR62266 contributed to reduce plant height, total plant length, enhance tiller number, root number and root dry weight. As IR62266 is a short parent with shallow root and more tiller number, such an effect is explainable. A major QTL, explaining 20% of variation for plant height and flanked by RG109/ME10_14, was detected at LaD of 6.17. This genomic segment is close to the map position of sd-1, a major gene controlling semi-dwarfism. On the other hand, of the two QTL for root: shoot length ratio, one QTL on chromosome 1 (CD0345/RZ909) enhanced the ratio. This indicates that inferior parent (IR62266) can also contribute favorable alleles for root traits.