Cluster Analysis And Genetic Map Construction Of Low-nitrogen Tolerance In Barley At Seedling Stage

Barley is the fourth largest cereal crops that the planting area is less than wheat,maize and rice. It is also one of the main crops in our country with short growth periodand strong stress resistance varieties. It is divided into malting barley and fodder barleyaccording to its production purposes. Grain yield is the most important evaluation indexand relates to nitrogen uptake and utilization efficiency. Therefore, in order to guaranteethe quality and production of barley, screening and cultivating barley varieties thatnitrogen utilization ratio was higher in low nitrogen tolerance can reduce nitrogen rates,and is one of the important approaches of effective use of chemical fertilizer resources,reducing environmental pollution, lowering production cost, improving the nitrogen useefficiency and ensuring good quality of barley.The study carried out hydroponics’ experiment in22major barley varieties atseedling stage under low nitrogen stress and normal nitrogen supply conditions all overthe country. We investigated mean analysis on character comparison of agronomic traitsand the character of the barely at seeding stage in low nitrogen tolerance. Aroundnitrogen physiological utilization efficiency and related morphological index, wecompared the variations of characters associated with low nitrogen tolerance in differentbarley varieties at seedling stage under two nitrogen supply levels. We closedappropriate screening evaluation index as barley varieties at seedling stage in lownitrogen tolerance. Construction of DH group of the barley by anther culture in vitrowas used as genetic map in barley in low nitrogen tolerance by molecular marker. Itprovided scientific basis for the barley at seeding stage in low nitrogen tolerance. Mainresearch results are as follows:1. A hydroponics’ experiment was carried out in more than twenty barley cultivarsat seedling stage which introduced from Jiangsu, Shanghai, Hubei, Heilongjiang, Henan,and Gansu, Qinghai and Xinjiang provinces and districts. We investigated variations ofcorrelated characters in low nitrogen tolerance. Therefore, the relative shoot dry weight,relative plant dry weight and relative tiller number in low nitrogen tolerance at seedlingstage would probably be the important traits for screening barley.2. Results showed that there were big differences in relative shoot dry weight,relative plant dry weight and relative tiller number in two nitrogen conditions. These can be used as the standard of clustering analysis. We clustered these varietiessystematically and divided them into three broad categories and some subgroups. Theobtained results provide the valuable information for using barley germplasm resourcesto parental combination, selecting and breeding new barley varieties of high N useefficiency.3.84doubled haploid (DH) derived from BI-04×BI-45by anther culture, was usedas mapping population in barley. The result was covered the applications of SSRmarkers in the construction of barely in low nitrogen tolerance molecular genetic map.Provided the basis of map-based cloning of a major QTL for barely character andbreeding new barley varieties in low nitrogen tolerance.