Identification of aroma and aroma genotype in local specific fragrant rice varieties from Guangxi

Objective The aroma and aroma gene genotypes of fragrant rice varieties from different places in Guangxi were identified to provide theoretical basis for exploiting and utilizing the local germplasm resources of Guangxi fragrant rice and breeding high quality characteristic fragrant rice varieties.Method The aroma and aroma genotypes of 179 local fragrant rice germplasm resources in Guangxi were identified by combining the traditional aromatic identification methods (KOH soaking and grain chewing) and molecular marker technology.Result In the 179 tested varieties,167 fragrant varieties were detected by KOH soaking,and 124 fragrant varieties were detected by grain chewing.Among the varieties were identified as fragrant rice by grain chewing,97.58% of which also could be detected by KOH soaking.But among the varieties identified as fragrant rice by KOH soaking,only 72.46% of which could be detected by grain chewing.Seventy-one varieties were detected alleles by molecular marker method,accounting for 39.66% of the total number of the tested varieties.The alleles were mainly InDel7 and InDel4-5 alleles,only one was detected with InDel2 allele,forty were detected with InDel7 allele,thirty-seven were detected with InDel4-5 allele,but seven were detected InDel7 allele and InDel4-5 allele at the same time,no varieties were detected with InDel13 allele.Among 71 varieties with aromatic alleles,69 were identified as fragrant rice varieties by chewing and/or KOH soaking,with the correct rate reaching 97.18%.The aroma phenotype of 121 varieties identified as fragrant rice by KOH soaking and grain chewing were clear,but only 55 varieties were identified the known aroma alleles,with a detection rate of 45.45%.The tested varieties from Baise could be detected the aroma alleles,which accounted for 53.19% of the fragrant rice varieties in the city.The varieties contained InDel2 allele,InDel7 allele and InDel4-5 allele,but Indel7 allele was predominant.The tested varieties from Hechi could be detected aroma alleles,and the percentage of aroma alleles in the fragrant rice varieties was the highest,up to 64.10%.Only two fragrance genotypes were detected,and Indel4-5 allele was predominant.The proportion of aromatic alleles detected in Liuzhou and other cities were far lower than those in Baise and Hechi.ConclusionLocal fragrant rice varieties in Guangxi have strong regional characteristics,and the aromatic allelic genes of different regions are very different.New aroma genes or aroma alleles may be found in Guangxi local fragrant rice varieties except the reported fragrancearoma alleles.The four known alleles are not enough to detect all varieties of fragrant rice.Combining methods of grain chewing and KOH soaking at the same time can obtained fragrant rice varieties more accurately.