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Breeding And Combining Ability Analysis Of Rice Restorer Lines With Low Amylose Content

Posted on:2023-06-08Degree:MasterType:Thesis
Country:ChinaCandidate:P WenFull Text:PDF
GTID:2543307112961469Subject:Agriculture
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Amylose content is the main factor affecting rice eating quality.The amylose content of rice with good taste is generally medium or low.Reducing amylose content is an important direction to improve rice quality.In the early stage,our research team used rice restorer lines Changhui 121,Changhui 881 and Changhui T025 with high amylose content as materials,and improved the amylose content of rice restorer lines with high amylose content by backcrossing with varieties with medium or low amylose content combined with molecular marker assisted selection,and obtained 180 BC2F2improved lines with low amylose content.In this study,6 lines of BC2F6generation were selected through marker detection,amylose content determination and agronomic traits investigation for 5generations.Six improved restorer lines with good agronomic characters,namely PW16,PW19,PW22,PW52 and PW58,were screened for incomplete diallel cross with 7 male sterile lines,namely Taifeng A,1721A,Jinxiang A,Hong1A,Guoxiang A,Vientiane A and Taixiang A,for analysis of combining ability.The results are as follows:1.The 180 BC2F2improved strains were obtained by marker detection,amylose content determination and agronomic traits selection in five generations of Nanchang season in 2019,Hainan season in 2019,Nanchang season in 2020,Hainan season in 2020and Nanchang season in 2021.2.The amylose content of BC2F5120 lines in the southern breeding season of Hainan in 2020 was determined,and 45 BC2F5improved restoring lines had amylose content of12%~19.45%.For PW16,PW19,PW22,PW37,PW52,PW58 with excellent agronomic traits,the Wx gene sequencing results of six improved restorers showed that the base at the donor+1 position of Wx gene in intron 1 of the six improved restorers and donors was T,the number of(CT)n repeats in exon 1 was 18,the number of(AATT)n repeats in intron 1was 5,and their amylose content was 13.4%,12.6%,12.3%,16.27%,19.45%,and 15.79%,respectively.3.In the southern breeding season of Hainan in 2020,incomplete diallel cross and combining ability analysis were conducted between the six improved restorer lines selected and Taifeng A,1721A,Jinxiang A,Hong1A,Guoxiang A,Vientiane A,and Taixiang A.The results showed that the variance of combining ability of each yield agronomic character of the improved restorer lines and male sterile lines reached significant differences,and the analysis of general combining ability(GCA)showed that PW19,PW22,PW58,Hong1A,Taixiang A,and Jinxiang A had high general combining ability;The analysis of SCA effect showed that PW16/Jinxiang A and PW58/Guoxiang A had higher SCA.The analysis of variance contribution rate of genotype showed that the primary branch,total grains,full grains,seed setting rate,empty grains,plant height,and yield per plant were mainly affected by additive genes,while the spike length and effective panicles were mainly affected by special combining ability(SCA).
Keywords/Search Tags:rice, Amylose content, Wx gene, Combining ability, GCA, SCA
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