| Starch is an important component of wheat kernel,accounting for 65~70% of wheat kernel.It mainly exists in wheat endosperm in the form of starch grain.The morphology and internal structure of starch grains affect the edible quality of wheat products.Xinhuamai 818 is a new variety of medium gluten wheat which has been approved recently and is suitable for making noodles.The early stage of the laboratory by fast neutron induced mutant library of the varieties,on this basis,this study determined the mutant library M3 generation different strain changes,the amylose content in seed selecting and considerably increase the amylose content of mutant materials,starch is measured and the physical and chemical properties,for the future breeding of new varieties of wheat resistant starch provided germplasm resources.The main research results are as follows:(1)Mutants with significantly increased amylose were screened out.Use Irish Megazyme company amylose/amylopectin kit in xin hua mai 818 M3 generation fast mutant library,249 mutant materials were measured relative amylose content and found 249 copy of mutant materials relative amylose content is normally distributed,most mutant amylose content distribution between 34 ~ 40%,relatively higher than wild type of amylose mutants 157,accounting for 63.05% of the total number of variants,down 92,compared with wild type accounted for 36.95% of the total number of mutants.Compared with wild-type,24 mutants with average amylose content of 18.62% higher than wild-type were selected by one-way analysis of variance,which was helpful for further breeding of starch resistant wheat varieties.(2)The physicochemical properties of starch with high amylose mutant were determined.The national standard method was used to determine the total starch content of the mutant with high amylose content.The results showed that the total starch content of the mutant with high amylose content was 77.39%,67.25% and 71.82%,which was slightly higher than that of the wild type with 70.32%,indicating that the variation of the total starch content was small.The gelatinization characteristics of the selected mutants with high amylose content were determined.The results showed that the peak viscosity,the trough viscosity,the final viscosity,the slack value and the regenerative value were all increased compared with the control.The peak viscosity increased by 5.85% compared with WT.The low valley viscosity increased by6.37% compared with WT.The slack value was increased by 4.44% compared with WT.The final viscosity increased by 5.53% compared with WT.The regeneration value increased by1.64% compared with WT.The results showed that the variation of starch gelatinization characteristics was small,and the starch quality did not change significantly,which was beneficial to maintaining the processing quality of cooked pasta.(3)The structural characteristics of starch in high amylose mutant grains were determined.The number of starch granules of type A(>9.8 μm in diameter)and type B(< 9.8μm)in the high amylose mutant was very similar to that of the wild type.The volume ratio and surface area of B-type starch granules decreased in the wild type,while the volume ratio and surface area of A-type starch granules increased slightly in the wild type.The results showed that the increase of amylose content in the mutant was due to the increase of the volume and surface area of type A starch grains and the relative decrease of type B starch grains.The crystallinity of the high amylose mutant was measured by X-ray diffractometer.The results showed that the crystallinity of the high amylose mutant ranged from 27.91 to34.03%,with an average value of 31.11%,which was 7.52% higher than that of the wild type.The results showed that the increase of amylose content in the mutants resulted in the increase of crystallinity,which was conducive to the formation of resistant starch. |
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