Genetic Model Analysis Of Malting Quality Traits In Barley

Barley is the fourth major cereal crops in the world in terms of yield and plant area. According to the use of barley, barley can be clustered into malting barley, feeding barley and health food barley. More and more attention has been paid to barley malting quality. Previous studies indicated that barley malting quality was quantitative traits controlled by polygene. A DH population derived from TX 9425 and Noso Nijo were used to further study the genetic model of malting quality. Genetic analysis of malting quality was conducted using major genes plus polygenes mixed inheritance model and the genetic parameters were estimated. Following was the major results:1. Seven malting qualities including diastatic power, malt extract, kalbach index, total nitrogen, soluble nitrogen, alpha amino nitrogen and wort viscosity were analyzed in this study. All the seven malting qualities were significantly different between two parents and DH lines, indicating there was wide genetic variation for the malting barley among these plant materials. The character of frequency distribution of malt quality traits shows skewness or multimodal phenomenon, that there may be a major genes or tiny effect polygene, method of analysis can be used to structure genetic model analysis, and estimating its genetic parameters.2. The genetic of all the seven malting qualities was fit for two major genes plus polygenes model (E). However, the model for one malting quality was not the same between two years, indicating the malting quality was affected by environmental factors. Both malt extract and kalbach index fit for two major inhibition genes plus polygenic inheritance model (E-19). Total nitrogen fit for two major additive genes plus polygenic inheritance model (E-2-6). Wort viscosity fit for two linkage-overlap major genes plus polygenic inheritance model (E-2-8) in 2012 but two link-additive epistatic major genes plus polygenic inheritance model (E-2-1) in 2013. Alpha amino nitrogen fit for two models, two link-recessive major genes plus polygenic inheritance model (E-2-5) and two link-additive epistatic major genes plus polygenic inheritance model (E-2-1). Soluble nitrogen fit for two complementary major genes model (E-1-7) in 2012 but two dominant epistatic major genes plus polygenic inheritance model (E-1-4) in 2013. The best fitting model for diastatic power were two complementary major genes model (E-1-7) and two additive effect major genes model (E-2-0).3. Correlation analysis between malting qualities showed that alpha amino nitrogen was significantly positive to soluble nitrogen, kalbach index and diastatic power. Soluble nitrogen was significantly positive to kalbach index and diastatic power. Total nitrogen was significantly negative to malt extract and kalbach index, indicating reducing protein content could improve malt extract and kalbach index in breeding and raw material production. Therefore, overall consideration of all malting quality is necessary in quality breeding programs.