Identification And Genetic Analysis Of Rice Quality Phenotypes In Whole Grain Rice

Whole grain rice(WGR)is the rice that has not been processed in any way.It retains all the components of the seeds,which contains many beneficial compounds,including anthocyanins,flavonoids,phenols,dietary fibre,fatty acids,protein,vitamins,etc.Due to its health benefits,it was considered a functional food.However,poor taste has limited its consumption.It is therefore crucial to study the potential phenotypes of WGR to improve its palatability quality and to advance research on the genetic and molecular mechanisms of its palatability.This study identified the appearance structure and physicochemical properties of the testa,aleurone layer,and endosperm of 4 rice varieties: Hua Moxiang,Hei Shuai,9311,and Huang Huazhan,and analyzed their correlation with taste quality.And use GWAS and BSA to locate QTLs of RVA.The main results are as follows:(1)The cell size,relative area and width of aleurone layer from 4 rice were significantly correlated with the overall score of cooked WGR on sensory evaluation(R =-0.84,0.93,0.79).Breakdown value and setback value of 4 rice from RVA were also significantly correlated with the overall scores(R = 0.72,-0.90).(2)Among the glutinous rice varieties,HMX possessed more short-chain starch(DP≤11)than HS about 10.55%;HS’s more long-chain starch led it had a stable structure,which may affected its texture and taste.(3)We concluded that rice variety with fewer long-chain starch,lower crystallinity,higher breakdown value,lower setback value,and pasting temperature maybe had a fluffy texture,high viscosity,and good taste quality.(4)There was extensive variation in the RVA of the germplasm populations,which ranged from 18.12% to 37.69%.44 major QTLs were detected by GWAS,including cloned genes,such as Waxy,ALK,OsSSIIb and Kala4.Effect loci of peak viscosity were located within the markers 4-23 to 4-24,6-01 to 6-02 and 6-03 to 6-04 by BSA.As a result of this study,we developed several WGR phenotypes about taste,which provide a phenotypic reference for taste quality evaluation of WGR.At the same time,we performed the localization of OTLs for RVA,and identified several significantly related SNPs on other chromosomes,besides the reported genes like Waxy,ALK,Kala4,and OsSSIIb,providing OTLs information for genetic analysis of RVA.