INVESTIGATION AND GENETIC ANALYSIS OF YIELD TRAITS AND DROUGHT TOLERANCE OF ORYZA RUFIPOGON USING ADVANCED BACKCROSSING INBRED POPULATIONS

Abstract

      Rice (Oryza sativa L.) is one of the staple cereal crops of the world and it is one of the main sources of carbohydrates for nearly one-half of the world's population. So, an increase in rice yield to satisfy human needs is a pressing requirement. Agronomic characters such as high plant, length of panicle, length of flag leaf, number of seed per panicle, the weight of thousand rice, length and width of rice and tolerance to salt are the deciding factor for yield in rice. Today's rice is derived from the common wild rice (Oryza rufpogon) 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 213 lines including 1.286 introgressed fragments with an average length of 6.511 Mb, covering 93.59% of the donor parent’s chromosomes. The agronomical characters of 213 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.