Genetic Analysis And Gene Mapping Of No Lateral Root Mutant RM109 In Rice(Oryza Sativa.L)

Rice root system plays an important role in the growth process,and lateral roots is top priority of rice roots.developed root system play a decisive role in resistance to adverse environmental conditions for rice.In this study,we measured the maximum tiller number,plant height,spike number,panicle length,grain number per panicle,filled grains number per panicle and spikelet fertility of no lateral root mutant RM109 and the original variety Oochikara under the different nitrogen levels.We also measured the maximum root length,adventitious root number and lateral root number of RM109,Miyang 23 and RM109/Miyang 23 hybrids F_1,F₂ population at seedling stage.Agronomic characters under the same nitrogen level and the difference of agronomic characters under the difference nitrogen level between RM109 and Oochikara was compared and analyzed.Using F₂ population to analyse the correlation of root traits about the maximum root length,adventitious root number and lateral root number at seedling stage,and F₂ population were classified according to phenotype of the number of lateral root.RM109,Miyang 23 and RM109/Miyang 23 hybrids F_1,F₂ population was used for genetic analysis and gene mapping for no lateral root mutant trait.In addition,RM109 and Oochikara was used for sequencing comparison analysis of the auxin gene related to the near position,The main results are as follows:1.There ware extremely significant difference between RM109 and Oochikara in maximum tiller number,plant height,spike number,spike length,total spikelets number per panicle and filled grains number per panicle on the same nitrogen level,show that lateral root and the main agronomic traits,including yield traits are closely related.Trait differences of maximum tiller number,spike number,total spikelets number per panicle and filled grains number per panicle between the two nitrogen levels was significant difference between RM109 and Oochikara,indicate that lateral root directly effect on response and absorption of nitrogen in rice.2.For F₂ population derived from a cross of RM109/Miyang23,distribution of number of lateral root is abnormal,and it was very significantly negative correlated with maximum root length and number of adventitious roots.Maximum root length and adventitious root number are quantitative traits,and it showed a significant positive correlation in both.3.According to number of lateral root,F₂ population derived from a cross of RM109/Miyang23 can be obviously divided into three categories:normal root type,less lateral root types and no lateral type.Chi square test for the proportion of the three types is generally consistent with the 1:2:1,showed that no lateral mutant character is controlled by a single gene,and the mode of inheritance was not completely dominant.4.The gene controlling no lateral mutant character was preliminarly located in marker interval RM15879-RM5475 on chromosome 3.The interval size is about 3.1cM,and specific physical distance is about 450kb.5.Use RM109 and Oochikara to make sequencing analysis on auxin related genes located near gene mapping locus.There are several nucleotides of promoter region of the gene OsIAA13 differences between RM109 and Oochikara,speculate that no lateral mutant character of RM109 is very likely caused by mutations in the promoter region of the auxin gene OsIAA13.