Evaluation Of Winter Wheat (Triticum Aestiuvm L.) Germplasms And Its Utilization In Wheat Breeding

Wheat (Triticum aestivum L.) is one of the most important corps in the world. In China, both the total yield and trade volume are the first in the world. However, there is still gap in quite aspects between China and developed countries. The genetic diversity study is the base of breeding high quality varieties and is necessary and important for wheat breeding. The main results are as follows:1 A total of 42 wheat cultivars were analyzed based on nine agronomic traits. There was a relatively wide variation in agronomic traits, the coefficient of variation (CV) of the sterile spikelet number was highest (61.39%), and the coefficient of variation of the effective tillers numbers per plant (21.59%), the number of kernels per spike (18.85%), grain weight per plant (16.92%), ear length(16.45%),the length of neck-panicle node(12.65%),effective spikelet number(10.27%)and plant height(9.43%)decreased in turn, and the variation coefficient of the thousand-grain weight was smallest (6.06%). The average of sterile spike was 1.01(between 0.20 and 2.40), the average weight of thousand-grain is 44.70g (between 37.68 and 51.39g).2 The diversity indexes of the studied nine traits of the 42 wheat cultivars were different, wherein the diversity index of Spike Neck was highest (1.94), and the index of effective spikelet was lowest (1.66). The results also showed that the diversity index of the varieties in Henan, Hebei, Shandong and Shanxi provinces were 1.83, 1.82, 1.73 and 1.62, in which the diversity index of the varieties in Shanxi province is lowest.3 Based on longest distance (Euclidean distance) method, all the cultivars in 7.5 could be clustered into three major groups, in which the first subtype contained 2 cultivars, the second and third subtype both contained 20 cultivars, accounting for 46.7%. The results indicated that the genetic basis of the varieties in the said four provinces was rather narrow.4 A total of 104 wheat cultivars were studied on the SSR genetic diversity analysis. The results showed that 22 SSR primers amplified 180 distinctive bands, in which 139 bands were polymorphic, which accounted for 77.2% of the total bands. Each primer amplified 3 to 10 polymorphic bands with the average of 6.32. The value of allelic polymorphic information content (PIC) ranged from 0.55 to 0.87 on an average of 0.71. The polymorphic loci of wms375 and wmc406 were 10, indicating that the polymorphism of SSR marker loci in the tested wheat varieties was high.5 According to the analysis of SSR molecular marker genetic diversity, the genetic similarity between pairing varieties ranged from 0.23 to 0.86, with the average value of 0.51. A total of 104 wheat varieties were divided into three groups and eight subgroups, the phylogenetic tree were related with the geographical origin of the wheat varieties.