Development Of The Blast Resistant Rice Through Functional Marker Of The Pi25Gene And Gene Mapping Of The Lax Mutant In Indica Rice

Rice is one of the world’s most important food crops.Rice yield was not only affected by the disease, especially the rice blast, but also influenced by morphological characteristics of panicle. Therefore, on the one hand, the cultivation of rice blast resistance breeding varieties becomes one of the goals of the workers; On the other hand, in order to further improve the rice yield potential, in recent years, the ideal plant type/panicle type have become important breeding targets. This paper used Pi25gene functional molecular marker to screen resistance to rice blast three system maintenance line. The main results are as follows.1.Use strong rice blast resistance type Digu B as backcross parent,crossing with good maintenance line Qian1B、Jin23B、Ganxiang and so on respectively.Through successive plant generations backcross, breeding forty good agronomic characters maintain system and sterile line.2. Molecular identification results and field resistance identification results were essentially identical.In addition, this paper also positioned a LAX gene that was related to pancile morphology, the main results are as follows:1. The lax mutant come from the Zhehui7954by the EMS mutagenic. The mutant presented the secondary branch numbers and third branch numbers increased significantly, but the spikelet numbers reduced markedly.Genetic analysis indicated that one of the lax mutations was controlled by a single recessive nuclear gene. The LAX gene was mapped on the long arm of chromosome4by SSR markers between RM16887and RM16904.There were14candidate genes in this area.2.The fourteen candidate genes were determined by bioinformatics.The sequencing comparison analysis showed that, there was single base substitution happened in clone LAX2gene encoding area that caused the codon into termination codon.3.Real-time quantitative PCR results showed that between the wild type rice and mutant,pancile morphological characteristics related genes. Ghd7gene had significant differences in expression quantity. 4.The quality analysis for the lax mutant indicated that among the aspect ratio polished rice rate, the whole polished rice rate, amylose content had no significant difference,expect the rice chalkiness.