Construction of introgression lines of Oryza rufipogon and evaluation of important agronomic traits.

Cultivated rice (Oryza sativa) originated from common wild rice (Oryza rufipogon) and inherited its advantages. However, during the rice domestication process, some valuable features of wild rice, such as tolerance to biotic and abiotic stress, were lost. To fully utilize wild rice germplasm resources, we constructed a set of introgression lines (ILs) using a common wild rice material from Lingshui, China. A set of high-resolution InDel molecular markers with an average interval of 2.39 Mb were designed to carry out marker-assisted selection and identification of segment characteristics. The ILs contained 77 lines including 1.286 introgressed fragments with an average length of 6.511 Mb, covering 93.59% of the donor parent's chromosomes. The agricultural traits of 77 lines were investigated. Many old quantitative trait loci (QTLs) involved in plant height, awn length, seed traits and other characteristics reappeared in our ILs, proving that our system was reliable. Further, many new QTLs were identified. A QTL related to drought tolerance located on chromosome 4 was thoroughly elaborated. This set of ILs provides a new resource for utilizing the excellent features of wild rice.