QTL detection of amino acid content in grains of rice using advanced backcross introgression lines

Improvement of grain quality, such as protein content (PC) and various amino acid contents (AAC) is an important breeding objective in rice (Oryza sativa L.). One hundred and thirty-two advanced backcross introgression lines derived, from a cross between japonica cultivar Xiushui09 and indica breeding line IR2061 were developed and used to study the inheritance of AAC in rice. A total of 40 AAC QTLs were identified and located on all chromosomes except that 7 and 9 in milled rice, which can explain the total phenotypic variation ranging from 4.97% for Ser content to 26.30% for Thr content with an average of 10.33%. Eight QTL clusters were identified on chromosomes 2, 3, 5, 6 and 11. Among them, the QTL cluster in the region of RM536-RM229 on chromosome 11 was exclusively associated with essential amino acid content. Many regions containing QTL clusters had a wide coincidence with the loci reported previously. These results provided some useful information on marker-assisted selection (MAS) for quality by marker-assisted controlling the balance of various AAC.