Association Among Friabilin, Wheat Kernel Hardness And Dough Properties And Identification Of Pinb Mutation In Shandong Province Common Wheat

Kernel hardness is one of the most important characters which influence the milling performance and end-use quality of common wheat (Triticum asetivum L.). It is beneficial for improving wheat quality to study biochemical and molecular inheritance basic of kernel hardness. Materials used in this study are 65 wheat varieties from Shandong Province. All of the surveyed materials are used to measure kernel hardness by Single Kernel Characterization System, to separate the protein friabilin, puroindoline by modified SDS-PAGE, A-PAGE and to detect the variation of puroindoline alleles with PCR and site-specific cleavage with the restriction enzyme. Dough rheological properties of all the materials, mainly including the farinagraphs and extenigraphs, are measured and the correlations among the kernel hardness, protein, dough rheological properties are analysed. The main results obtained in this study are summarized below.1. Measured by SKCS, there are 26 hard wheat varieties whose hardness indexes were more than 60, 16 soft varieties whose hardness indexes were less than 40 and 23 mixed varieties whose hardness indexes were between 40～60. They occupy 40%, 24.6% and 35.4%, respectively in whole.2. Modified SDS-PAGE and A-PAGE are used to separate friabilin and its main subunit PINA and PINB. The results indicate that the two means are very efficient. In these means, some time and reagent are saved at the same time. Therefore, these two modified means are good at the biochemical study of the wheat hardness.3. Grain hardness is negative correlation with level of friabilin protein. The results show that high level of friabilin protein in soft wheat and relatively low level in hard wheat, with correlation coefficence -0.71 at 1% signification level.4. A certain correlation is existed between the protein level and dough rheological properties. In this study, the correlations, between the protein level and dough rheological properties including the farinagrams and extenigrams, are analysed. The results show that prominent correlation is existed in friabilin protein, puroindoline protein and some of the dough rheological properties. There is a significant correlation between protein quantity and dough water absorption, valorimeter and extensibility. The correlation coefficient is 0.36 at 1% signification level between protein level and dough water absorption, however, the correlation is negtive among the protein and valorimeter, extensibility. Therefore, the hardness protein will be the marker of some dough rheological properties.5. The identification of Pin gene for 65 wheat varieties shows that Pina-Dla/Pinb-Dla exists in all the soft wheats. In other hard and mixed wheats varieties, there are Pinb-DIb,Pinb-Dlc,Pinb-Dld,Pinb-Dle and Pinb-Dlf .