| Guizhou is a province with large rice landrace germplasm resources.The unique geographical location and landform conditions have created diversified climate and ecological environment,and bred lots of rice landrace resources with good quality and good resistance.The abundance of crop germplasm resources and genetic diversity are an important basis for excavating excellent genes and breeding new varieties.In order to better meet the needs of modern breeding,studies on the rice landrace resources in Guizhou,and fully excavates and utilizes its genetic potential to realizes the transformation from the advantage of germplasm resources to the advantage of gene resources,which will provides theoretical basis and material support for rice breeding in Guizhou province.In this study,we investigated the genetic diversity and population genetic structure of 273 rice landrace germplasm resources in Guizhou province,evaluated the main quality traits,analysis the diversity of starch synthesis-related genes,and carried out the association analysis between starch synthesis-related genes and eating and cooking quality traits in tested rice landraces population.The main results are as follows:(1)53 pairs of SSR primers were used to analyze the genetic diversity and population structure of 273 rice landrace germplasms from several areas in Guizhou province.The results showed that a total of 182 alleles were detected from 53 SSR markers,and the observed number of alleles per locus ranged from 2 to 6,with an average of 3.43.The average effective number of alleles was 2.0145.Shannon’s information index ranged from 0.2620 to 1.5828,with an average of 0.7788.Nei’s gene diversity index ranged from 0.1333 to 0.7723,with an average of 0.4325.The polymorphism information content varied from 0.1266 to 0.7366,with an average of0.3680.UPGMA clustering analysis based on Nei’s genetic distance divided 273 resources into two groups,including 240 and 33 materials,respectively.The results of population structure analysis were two divided groups,including 242 and 31 materials,respectively.Among 273 rice landrace germplasms,Q values of 262 materials(95.97%)were greater than or equal to 0.9,and only 2 materials were less than 0.6 in Q value,which were classified into admixed group.The results of population structure analysis were similar to those of UPGMA clustering.(2)The variation analysis of quality traits showed that percentage of grains with chalkiness,the degree of endosperm chalkiness,amylose content,gel consistency,alkali spreading value,water absorption rate,elongation rate and expansion rate of the tested materials had a large degree of dispersion.Most of the rice landrace germplasm resources in Guizhou belonged to medium and high amylose content,medium and hard gel consistency,medium and high gelatinization temperature.The correlation analysis of quality traits showed that there were significantly and positively correlations among the brown rice rate,milled rice rate and head rice rate were.Brown rice rate,milled rice rate and head rice rate were negatively correlated with chalkiness.The amylose content was negatively correlated with gel consistency and alkali spreading value.And there were significantly and positively correlations among water absorption rate,elongation rate and expansion rate.Principal component analysis of quality traits showed that most of the related information of quality traits could be summarized by four principal components,which were appearance factor,physical and chemical factor,processing factor and chalkiness factor,and the cumulative contribution rate of the four principal components was 70.609%.(3)A total of 126 alleles were detected from 58 loci of 20 starch synthesis-related genes in Guizhou rice landrace resources.The number of alleles varied from 1 to 4,with an average of 2.17.The number of effective alleles ranged from 1.0000 to 3.1081 with an average of 1.3850.Shannon information index ranged from 0 to 1.2456,with an average of 0.3841.The gene diversity index ranged from 0 to 0.6783,with an average of 0.2224.The polymorphism information index ranged from 0 to 6239,with an average of 0.1921.UPGMA clustering analysis of starch synthesis-related genes showed that 273 rice cultivars were divided into two groups,including 243 and 30 materials,respectively.A total of 97 haplotypes were detected in 20 starch synthesis-related genes,with a minimum of 2 and a maximum of 10 haplotypes.(4)58 loci of 20 starch synthesis-related genes were used to association analysis with cooking and eating quality traits in 273 Guizhou rice landrace germplasm resources.29 and 20 marker loci were detected by GLM MLM,respectively.GLM and MLM association analysis showed that 18 identical marker loci were associated with six quality traits,including amylose content,gel consistency,alkali spreading value,water absorption rate,elongation rate and expansion rate.The mutation in the promoter and 9th intron of PUL gene accounted for the highest variation of glue consistency and water absorption rate(3.88% and 3.43%,respectively).The mutation in the exon 6 of GBSSI gene accounted for 6.02% of base extinction and 7.31% of elongation variation,respectively. |
PDF Full Text Request