The Biological Characteristics And Genetic Diversity Of Aegilops Tauschii Coss.

Aegilops tauschii is classified as Aegilops and it is an annual or biennial malignant grass weed.Aegilops tauschii is an invasive species.The biological characteristics and growth conditions are very similar to wheat,and there has not a specific herbicide which is successfully effective on Aegilops tauschii and safe to wheat.In recent years,Aegilops tauschii has infested and widely spread in winter wheat fields in Shaanxi,Shandong,Henan,and Hebei provinces.It has been one of serious weed species in winter wheat fields.With abundant information of genetic diversity,differences of genetic diversity are important factors that have an influence on the efficiency of herbicide.Clearly finding out the genetic diversity of Aegilops tauschii populations were collected from different region,has great significance on precisely selecting herbicide and district management.In this study,40 Aegilops tauschii populations were collected from main areas of wheat production,and its main biological characteristics were observed.Furthermore,we have studied the difference of sensitive level of Aegilops tauschii to mesosulfuron-methyl.We have analysised the genetic diversity of different Aegilops tauschii populations at the level of acetohydroxyacid synthase?AHAS?and SSR,and demonstrated the relationship between genetic diversity and sensitivity to the herbicides.It will be a good foundation for screening effective herbicides on the purpose of controlling Aegilops tauschii.The main results showed as follows:1.40 populations of Aegliops tauschii were studied by biological characteristics.Coefficient of variation of different biological characteristics were different,the range of variation was 2.84%²9.75%,the highest coefficient of variation was grain weight which was 29.75%,and seed length was the lowest which was 2.84%.The order of different agronomic traits:seed length<seed width<nodes length of rachis<nodes width of rachis<awn length<number of grains per spike<thousand-grain weight<seed numbers per spikelet<plant height<number of tillers<grain weight.All populations were divided into three groups by using cluster analysis.2.Genetic diversity analysis of Aegilops tauschii by using microsatellite fluorescent SSR technique.40 Aegilops tauschii populations were collected from Shaanxi,Shandong,Shanxi,Hebei and Henan in China,were investigated by using 9 pairs of fluorescent primers distributed on the D genome of wheat,and a total of 27 alleles were amplified with the average of 3.The Shannon information index was0.4756,Polymorphism information content?PIC?value was 0.2538.The average of genetic similarity coefficient was 0.8288.The clustering figure showed that 40 populations of Aegilops tauschii were classified into 2 groups at the genetic similarity coefficient of 0.75.The first group contained 37populations,while another group only had 3 populations,the genetic similarity coefficient ranged from0.8824 to 1.0000,which showed that the close genetic relationship was obvious,and the genetic differentiation existed among the 40 Aegilops tauschii populations.3.The control efficacy of mesosulfuron-methyl on Aegliops tauschii.At the concentration of9.0000 g a.i./hm² and 33.0000 g a.i./hm²,the control efficacy of mesosulfuron-methyl ranged from22.75%to 54.61%and from 85.32%to 93.00%,respectively.The populations collected from Shaanxi,Shandong,Shanxi,Hebei and Henan had different tolerance level to mesosulfuron-methyl,LD₅₀ values were 13.9230,13.5943,11.4722,10.7399 and 9.5668 g a.i./hm²,respectively.4.The results of target enzyme activity assay revealed that tolerance level of Aegliops tauschii were different.At the dosage of 10^-4?M,enzyme activity of Pop-2,Pop-11,Pop-14 and Pop-33 were inhibited.While At the dosage of 10^-3?M,enzyme activity of Pop-4,Pop-7,Pop-8,Pop-18,Pop-26 and Pop-35 were inhibited.The inhibition rate of enzyme activity on 10 Aegliops tauschii populations were above 80%.