| Elymus nutans is a gramineous forage with extensive adaptability, cold resistant, strongly tiller, high nutrition value and good palatability. It is also the frequent resowgrass in the improvement of depleted grassland in alpine meadow.In the present study, seeds of 45 populations of Elymus nutans, attained from Gansu, Qinghai and Sichuan, were sowed in xiahe experimented station of Gannan state in 2008, biological characters and nutritional values were valuated in 2009 and 2010, respectively. The observed biology traits included growing season, growth rate, plant height, the unit area reproductive branch number, fresh yield, hay yield, ratio of fresh to dry yield etc., The nutrition quality of Elymus nutans evaluated at early flower stage included WSC, CP, NDF, ADF, TP, DDM and RFV content etc. Broad heritability analysis, gray incidence analysis, principle component and cluster analysis were applied to analyze all collected data to understand characters of biology and nutrition of Elymus nutans populations, and select some excellent materials to be used as breeding materials for different usage. The major results are as following:1. There were great variations on yield traits among 45 Elymus nutans populations. The fresh yield of first cipping and second cipping ranged from 2062.33-17268.25 Kg/hm2 and 902.67-5765.67 Kg/hm2 in 2009, respectively. The fresh yield of first cipping and second cipping ranged from 1790.74-7245.85 Kg/hm2 and 971.11-3583.26 Kg/hm2 in 2010, respectively. Some good materials based on the yield traits were found, such as GE13 and GE09, which had best compositive traits and could be used for breeding higher yield and high quality of Elymus nutans; 14 populations, GE16, QE35, GE45, GE01, QE40, GE32, GE12, GE19, GE05, GE44, SE27, GE17, GE22, and QE41 have higher production function, also could be used for breeding higher yield Elymus nutans;2. The nutrition value of Elymus nutans was good. In two years (2009 and 2010) nutritional evaluation at early flower stage, CP content ranged from 15.20%-22.93%, WSC content ranged from 2.22%-7.06%, ADF content ranged from 35.07%-46.42%, NDF content ranged from 57.28%-65.98%, relative feed value ranged from 76.86%-98.26%, which indicates that low NDF is an breeding object. Some materials with good nutritional values were found. Ten high sugar materials, including GE01, GE12, GE17, GE22, GE23, GE24, SE25, SE26, QE40 and QE42, five low fiber high sugar materials, including GE01, GE17, GE20, QE40 and QE42, three low fiber high nitrogen materials, including GE30, QE37 and GE45, four low fiber high phosphorous materials, including GE14, GE15, GE30 and QE43;3. The production and quality of Elymus nutans populations were influenced by genetic and environmental factors together. Plant height, the unit area reproductive branch number, fresh yield, hay yield, ratio of fresh to dry yield were decided by environment factors; CP, NDF, TP and RFV were also mainly decided by environment factor, while WSC, ADF and DDM were mainly decided by genetic factors.4. A comprehensive evaluation method was introduced for Elymus nutans, using Gray Incidence Analysis on production function and using combing Principle Component Analysis with Cluster analysis on nutritional traits. |
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