QTL Mapping For Pentosan Content And Identification Of Late Maturity α-amylase In Common Wheat

As one of the three major crops of wheat, second only to rice and corn, the world's annual output is over 600 million tons. The 20th century, early 90s, with "high-yield, high quality, efficient" as the goal of the new requirements of development of agricultural production, improving wheat quality is increasingly becoming an important objective of wheat breeding. As the Cereal Chemistry sector study on genetics of wheat quality depth, the influence of nutritional quality and processing quality of wheat, a major component-of less pentosan. China Xinan Mai area, wheat harvest is usually encountered rainy humid weather occurs sprouting. Resulting in deterioration of wheat quality, yield loss, severe and affect the quality of next year's planting. Therefore, the wheat harvest sprouting resistance in wheat breeding has been an important project.α-amylase activity increase is caused by one of the important reasons harvest sprouting, and some grains of wheat varieties in the late maturityα-amylase synthesis was low, so the performance characteristics of resistance to preharvest sprouting. However, some species mature late in the grain under the condition of no rainfall will be re-synthesis of some higher power pointα-amylase (pI6.3-7.5), the late maturityα-amylase (Late matureα-amylase, LMA), Leading to mature seed contains a high a-amylase activity, the field once the rain, harvest Sprouting immediately. So, late maturityα-amylase and sprouting a potential between the close relationship.To solve the above problems, this study on behalf of common wheat strains R97 and R146 high cross, built by several generations of cultivation of 103 recombinant inbred lines (RILs) population as materials, its pentosan traits were genetic analysis and QTL Mapping; use of 3,5-dinitrosalicylic acid method on wheat grain during maturation ofα-amylase activity were measured indicators combined with falling number of flour and polyacrylamide gel electrophoresis comprehensive analysis of isozymes, The main results are as follows:1. RILs populations pentosan content among families VariationRILs constructed by groups of wheat pentosan content among families showed that the total pentosans, water-soluble pentosans and insoluble pentosans average content of 7.270%,1.001% and 6.269%, variation range among were 4.827-8.371%, 0.659-1.556% and 3.931-7.556%, standard deviation, respectively 0.649,0.156 and 0.642, coefficient of variation were 8.93%,15.57% and 10.25%. TP and water-soluble pentosans and insoluble pentosans content showed a significant positive correlation. Water-soluble pentosan content is mainly concentrated in the 0.9 to 1.1%, and the total pentosan content mainly between 6.5 and 7.5%. By the standard deviation and coefficient of variation can be seen, the total pentosans, water-soluble and non water-soluble pentosan content varies widely between the families of genetic variation, genetic improvement potential. The characters in the RIL populations have greater genetic variation amplitude transgressive phenomenon. Investigation of the frequency distribution of traits pentosan analysis of the above groups of characters are in line with or close to continuous normal distribution, reflecting the separation of groups of genes control the number of features of the present study population for genetic mapping.2. QTL Mapping for Pentosan ContentThe composite interval mapping method (CIM) LOD= 2.5, total pentosans on grain, water-soluble pentosans and insoluble pentosans trait QTL analysis. TP (TP), water soluble pentosan (WSP) and non-water soluble pentosan (WIP) 3 of the 6 traits QTL loci were detected, these sites primarily in the 1A,4A,4D,6B appears. Where TP (TP) in the 4D detected a large QTL loci, LOD value of 15.27,0.17 additive effect, dominant effect was 0.21, the contribution rate of 24%. Water-soluble pentosan (WSP) in the 4A chromosome found a greater contribution to the rate of QTL (22%), the peak at the location on chromosome 82.2cM, while in 4D and 6B also found a contribution rate of 5% 10% of the two sites. Non-water soluble pentosan content (WIP) QTL were detected two sites are located on chromosome 1A and 4A, contribution rate of 7% and 14%3. Obtained by the analysis, the higher the total pentosan content of 17 families, the TP content higher than 8%, suitable for the cultivation of strong health food wheat. Also found that a total water-soluble pentosan content were lower in families, were 4.827% and 0.659%, suitable for use as feed wheat parents, from 7 April flowering. Pentosan content in wheat varieties than by genotype, but also by its impact on growth, flowering time later, the lower pentosan content.4. Late maturityα-amylase IdentificationFound that 1#,20#,52# family in the absence of sprouting seeds when mature synthesis of high pI (6.3-7.5)α-amylase isozymes-1. These results suggest that these families carry late maturityα-amylase gene. The land values were 108,284,187 seconds, that the existence of LMA expression of genes and environment interactions. Overall 30d after flowering in wheat can be detected in high pI (6.3-7.5)α-amylase isozymes-1, and higher activity. With the deepening development of amylase activity changed little until after flowering 42d, to maintain a high level of activity.52# pedigree seeds mature low pI (4.9-6.0) of the degradation of a-amylase- 2 faster. These results further late maturityα-amylase gene in the anti-sprouting China Xinan Mai District, nurturing guidance.