Pre-harvest Sprouting And Other Physicochemical Properties Of Waxy Wheats And The Establishment Of New Waxy Near-isogenic Lines

Since Nakamura successfully cultivated the first waxy wheat line in1995, many researchers have carried out a lot of studies on physicochemical properties, processing qualities, application and production of waxy wheats. Recently, China has also successfully developed a series of waxy wheat cultivars, such as Yangnuomai1, Tiannuo1, Shannuo1, etc.K107Wx1is a waxy line that has already been used in the selection of waxy wheat lines, which has a wx-D1mutant locus that is different from the wx-D1locus in Baihuomai. In this study we established a set of near-isogenic waxy wheat lines using K107Wxl as a donor parent, and Ning0088which possessed good agronomic traits as a recurrent parent to investigate the consequence of alternation in waxy gene donor on wheat bread making and noodle making quality.Pre-harvest sprouting is a complicated quantitive trait, both genetic and environment have big influences on its occurrence, many factors are associated with pre-harvest sprouting, including seed morphology, seed physiological properties, hydrolytic enzyme activities, seed dormancy, and so on. In this research, both plastic container and plastic bag method were used to assess the preharvest sprouting rate of6waxy lines and their background lines, RVA and Mixolab were applied to study the differences of a-amylase activities, water absorption in waxy and non-waxy wheat lines, respectively. The purpose was to find out the potential explanation for the differences and to provide a reference for the production of waxy wheats in the future.The conclusions from this research are as follows:1.On the assessment of preharvest sprouting rate, in both plastic container and plastic bag method, waxy wheat showed higher sprouting rate than that of non-waxy lines, also white wheat lines Zheng9023and Yang01-2and waxy lines under their backgrounds, all had higher sprouting rates than other red wheats, which was consistent with previous reports. In addition, with floral foams as spikes base, plastic container method proved to be an efficient way to assess the whole spike sprouting rate of wheat2.Falling Number of waxy and non-waxy wheats showed huge differences, falling number of non-waxy wheat were usually378-662s, while waxy wheats were generally less than100s. The result suggested that falling number could not serve as a precise criterion to assess the pre-harvest level of waxy wheat.3.On RVA viscosity tests for enzyme activities, the results showed that waxy wheat displayed higher peak viscosity when using silver nitrate as a dilute solution instead of water, the reason probably was that silver nitrate was used as an enzyme inhibitor. As in the water, waxy wheats tended to show lower pasting temperature, lower peak viscosity and decreased peak time. Also its value of minimum viscosity, final viscosity and setback were lower than non-waxy wheats.4.Mixolab results showed that waxy wheats displayed lower Torque value of C2, C3, C4, C5, and higher water absorption and longer C4time. Also, C1-C2value which represented protein weakening was higher in waxy wheats, however the C5-C4value which associated with starch retrogradation was found lower than non-waxy wheats.5.Correlation analysis indicated that several parameters in Mixolab had very good correlation with falling number, RVA parameters, water absorption. Since the value of falling number in waxy wheats were awfully low in general thus making assessing pre-harvest sprouting of waxy wheats using falling number unsuccessfully, researchers might consider using Mixolab as an efficient tool to determine wheat quality as well as pre-harvest sprouting.6.A set of near-isogenic waxy wheat lines using K107Wx1as a donor parent, and Ning0088which possessed good agronomic traits as a recurrent parent was established. To accomplish this task, both traditional cross selection and double haploids induced by maize pollen were applied. For the genotype aabbdd、AAbbdd、AABBdd、aaBBdd from traditional method,2、2、3、3lines were obtained, respectively. As for the DH method, there were15、16、17、11plants with genotype AAbb、aaBB、aabb、AABB, respectively; the remaining With the establishment of this special set of near-isogenic waxy wheat lines, it will enable us to further study the consequence of alternation in waxy gene donor on wheat bread making and noodle making quality. And hopefully help to cultivate and popularize more waxy wheats with better quality.