Rice Lodging Resistance Research And Preliminary Mapping Analysis Of QTL For Related Traits

Rice output per unit area ranks first in Chinese grain output per unit area and rice lodging is one of the important factors affecting the stable yield of rice.It is great significance for the stable and high yield of rice to study the key agronomic traits that affect rice lodging and to locate related traits.This experiment uses Zhenshan97B/IRAT109 recombinant inbred line population(F9)and 533 rice core germplasm resources as materials.21 phenotypic traits were measured in 25 days after full panicle.Through the correlation analysis and path analysis of 21 phenotypic traits,the relationship between traits and lodging index in the two rice populations was studied to improve the evaluation system of rice lodging resistance traits.K-mean clustering method was used to select rice varieties with high lodging resistance.Linkage analysis and association analysis were performed on the two populations respectively,and QTLs of related traits were co-located.The results of the study are as follows:1.The 21 phenotypic traits measured in 2017 and 2019 showed a normal distribution in the recombinant inbred line population,and showed different degrees of bidirectional superparental segregation.IRAT109 was shown as a low-value parent in rice lodging index traits.Among the 19 phenotypic traits determined in 2017,among the rice core germplasm resources,the panicle length(PL)has a minimum coefficient of variation of13.59%,ranging from 15.96 cm to 37.46 cm.The coefficient of variation of the short axis,long axis,thickness,and internode length increased successively.The variation coefficient of the lodging index(LI)was 46.90%,and the variation range was 0.63-7.22.The genetic variation was abundant.2.In the correlation analysis,the rice lodging index in the recombinant inbred line population and rice core germplasm resources has the same correlation with plant height and basal stem breaking-resistant strength,and the correlation coefficients with plant height are 0.329 and 0.315,respectively.The correlation coefficients of basal stem breaking-resistant strength are-0.534 and-0.715 respectively.The correlation coefficients between the second internode length in the core germplasm resources and the lodging index were 0.346 and 0.241,respectively.The dry matter content of the first and second internodes was related to the lodging index in the recombined inbred line population.The correlation coefficients were-0.488 and-0.471 respectively,and the correlations were all extremely significant.3.In the path analysis,the direct effects of basal stem breaking-resistant strength,dry weight of single stem,plant height,and the second internode length on the lodging index are consistent in the core germplasm resources of short and high stalk populations.The direct effects of dry weight of single stem,plant height,and the second internode length on the lodging index are all positive,and the direct path coefficient increases in turn from0.495(0.441),0.463(0.239),and 0.129(0.107).The direct path coefficients of the negative effect of basal stem breaking-resistant strength on the lodging index are-1.283and-1.228,respectively.4.Through the cluster analysis of rice core germplasm resources of different plant height groups,basal stem breaking-resistant strength is divided into 1-4 levels.23high-resistant varieties were screened from the short-stalk population: Baikehualuo,Jinyou 1 hao,Chengnongshuijing,IR 238,9311,Type 3,Palung 2,Dodda,Yangdao 2 hao,ir 6,JWR 221,452,Minghui 63,Gui 630,C70,Zhong 413,Gumei 2 hao,Zhongyouzao81,Buphopa,Ninghui 21,Zhongchao 123,Muguanuo-1 and 2428.20 highly resistant varieties were screened from the high-stalk population: N-2703,IRAT352,TB154E-TB-2,Zihui 100,Minbeiwanxian,Jinzhinuo,Taromolai1,Muguanuo-2,Hongqi 5,Babaili,Yuyannuo-1,GPNO 5055,Sereendan Kuning,Mitak,Lua Chua Chan,Simpor,SAI-BUI-BAO,Uwi,Padi Tarab Arab and Grassy.5.Rice plant height,center of gravity height,basal stem breaking-resistant strength,lodging index,the second internode wall thickness,and the first internode short axis have QTL co-localization in the recombinant inbred line population and rice core germplasm resources.Rice plant height was detected in the range of 37.60 Mb-38.80 Mb on chromosome 1,28.80 Mb-29.90 Mb on chromosome 4,and 8.90 Mb-11.50 Mb on chromosome 10.Basal stem breaking-resistant strength was detected in the range of 31.40Mb-31.90 Mb on chromosome 4 and 17.70 Mb-18.60 Mb on chromosome 10.The lodging index was jointly detected in the range of 37.60 Mb-39.00 Mb on the chromosome 1 and 16.90 Mb-18.70 Mb on chromosome 7.