Primary Mapping Of The Tiller Angle Gene In Rice CMS Line Pei'ai 64S

Rice is one of the world's four major food crops and is the main food for more than half of the world's population.Rice breeding has experienced bottlenecks in rice production in China,after undergoing two breakthroughs in dwarf breeding and heterosis utilization.In order to increase rice yield further,domestic and foreign breeders proposed a rice“ideal-type”model with production practices,in which the tiller angle is an important agronomic trait that constitutes a rice plant type.Appropriate tiller angles are important for shaping“ideal-type”rice and increasing yields.In this study,the cluster-type Pei'ai 64S and the dispersion-type IR841 were selected as materials.Regarding the derived F₂ progeny as gene-localized populations,located the genes controlling rice branching angle preliminarily.The main results of this study are as follows:?1?According to two gradient treatments of long daylight?16 hours light/8 hours darkness?and short daylight?12 hours light/12 hours dark light?on Pei'ai 64S and IR841,the results showed that under long-day conditions,the parental bifurcation angle is significantly larger than that under short daylight conditions,and the IR841has more significant differences in the angle of the dip at different illumination times.?2?Under dark conditions,the results showed that IR841 was more sensitive to gravity response,while Pei'ai 64S was relatively insensitive to gravity response.?3?The F₁ progeny bifurcation angle obtained by hybridization of Pei'ai 64S and IR841 was a large bifurcation angle.F₁ self-crossing obtained a continuous distribu-tion of F₂ progeny bifurcation angles.Genetic analysis showed that the genes control-ling rice bifurcation angle were quantitative trait genes.?4?At the heading stage of rice,the two parents were observed.The results showed that the base of the Pei'ai 64S bifurcation showed symmetrical growth between the base and the adjacent nodes,which made the bifurcation base stand upright;while the IR841 bifurcation base showed asymmetrical growth between the base section and the adjacent section,bending the base of the tiller to a certain angle.?5?Using the QTL-seq localization method,the target gene was mapped on chromosomes 6 and 8 which on the 4 candidate segments,the number of 3 genes were screened on chromosomes 6 and the number of 2 genes were screened on chromosomes 8.?6?Quantitative analysis of the effect of the cloned tiller angle gene on the bifurcation angle of the two parents showed that the expression levels of the four genes LAZY1,TAC1,PROG1 and LPA1 were not significantly different between IR841and Pei'ai 64S,indicating that these four genes were not the factors which cause the difference in tiller angles between the two rice materials.