Mapping and breeding value evaluation of a semi-dominant semidwarf gene in upland rice

Plant height is an important trait related to yield potential and plant architecture.A suitable plant height plays a crucial role in improvement of rice yield and lodging resistance.In this study,we found that the traditional upland landrace 'Kaowenghan'(KWH) showed a special semi-dwarf phenotype.To identify the semi-dwarf gene from KWH,we raised BC2 F4 semi-dwarf introgression lines(IL) by hybridization of the japonica rice cultivar 'Dianjingyou1'(DJY1) and KWH in a DJY1 background.The plant height of the homozygous semi-dwarf IL(IL-87) was significantly reduced compared with that of DJY1.The phenotype of the F1 progeny of the semi-dwarf IL-87 and DJY1 showed that the semi-dwarf phenotype was semidominant.QTL mapping indicated that the semi-dwarf phenotype was controlled by a major QTL q DH1 and was localized between the markers RM6696 and RM12047 on chromosome 1.We also developed near-isogenic lines(NIL) from the BC3 F3 population,and found that the yield of homozygous NIL(NIL-2)was not significantly different compared to DJY1.Breeding value evaluation through investigation of the plant height of the progeny of NIL(NIL-2) and cultivars from different genetic background indicate that the novel semi-dwarf gene shows potential as a genetic resource for rice breeding.

Plant height is an important trait related to yield potential and plant architecture. A suitable plant height plays a crucial role in improvement of rice yield and lodging resistance. In this study, we found that the traditional upland landrace ＇Kaowenghan＇ （KWH） showed a special semi-dwarf phenotype. To identify the semi-dwarf gene from KWH, we raised BC2F4 semi-dwarf introgression lines （IL） by hybridization of the japonica rice cultivar ＇Dianjingyoul＇ （DJY1） and KWH in a DJY1 background. The plant height of the homozygous semi-dwarf IL （IL-87） was significantly reduced compared with that of DJY1. The phenotype of the F1 progeny of the semi-dwarf IL-87 and DJY1 showed that the semi-dwarf phenotype was semi- dominant. QTL mapping indicated that the semi-dwarf phenotype was controlled by a major QTL qDH1 and was localized between the markers RM6696 and RM12047 on chromosome 1. We also developed near-isogenic lines （NIL） from the BC3F3 population, and found that the yield of homozygous NIL （NIL-2） was not significantly different compared to DJY1. Breeding value evaluation through investigation of the plant height of the progeny of NIL （NIL-2） and cultivars from different genetic background indicate that the novel semi-dwarf gene shows potential as a genetic resource for rice breeding.