The Differences Of Agronomic Traits And The Relationship With High Temperature Resistance In Different Cultivars Of Ryegrass

The aim of this research was to hold the differences produced by different ryegrass cultivars in the adaptability of Hunan and high temperature resistance and to select good ryegrass cultivars which suit Hunan climate environment conditions. The12ryegrass cultivars of Pinnacle, Premier, Yaqing, Swords, Special high, Barwoltra, Oregon tetraploid, Resist rust king, Night shadow Ⅱ, McGrady, Pandora and Winter green were selected in this research. Their agronomic characters of the growth periods, plant height, fresh grass yield, hay yield, seed yield, panicle number, total grain number per panicle, filled grain number per panicle, panicle long and1000grain weight and nutrients such as dry matter, calcium, phosphorus, protein, crude fiber and fat and crude ash content and physiological and biochemical indexes of resistance to high temperature such as chlorophyll content, relative conductivity, malondialdenhyde content, peroxidase activity and proline content were analyzed.The main results are as follows:1. The growth period of Oregon Tetraploid, Barwoltra and Resist Rust King of ryegrass cultivars of animal husbandry type and the growth period of Winter green of lawn type of ryegrass cultivar are the shortest244d. The whole growth period of Pinnacle of ryegrass cultivar of lawn type is the longest250d. There are obviously genetic differences between cultivars for the changes of plant height in different development stages among different ryegrass cultivars.The plant height of Oregon Tetraploid of ryegrass cultivar of animal husbandry type in the tillering stage, jointing stage, heading stage and booting stage is the highest. The plant height of Special High of ryegrass cultivar of animal husbandry type in maturity stage is the highest. There are obvious genetic differences between cultivars for the fresh grass yield and hay yield among different ryegrass cultivars.The fresh grass yield of Resist Rust King of ryegrass cultivar of animal husbandry type is the highest45889.60kg/hm2.The hay yield of McGrady of ryegras cultivar of animal husbandry type is the highest21977.65kg/hm2.2. There are obvious genetic differences for seed yield and composition factors of seed yield and ear length between cultivars among different ryegrass cultivars. The seed yield of of Special High of ryegrass cultivar of animal husbandry type is the highest2160.82kg/hm2. The seed yield of Premier of ryegrass cultivar of lawn type is the lowest863.87kg/hm2. The panicle number and total grain number per panicle and filled grain per panicle of Special High of ryegrass cultivar of animal husbandry type are all the most,which are respectively39panicle/plant,631grain/panicle and622grain/panicle.The panicle length of Pandora of ryegrass cultivar of lawn type is the longest43cm, and its1000grain weight is the heaviest3.75g.3. There are obvious genetic differences for the crude protein and crude ash and crude fat and crude fiber and phosphorus and calcium of quality components in different ryegrass cultivars.Among which, the crude protein and crude ash and phosphorus content of a McGrady of ryegrass cultivar of animal husbandry type are significantly higher than the other ryegrass cultivars.The calcium and crude fat content of Special High of ryegrass cultivar of animal husbandry type are significantly higher than the other ryegrass cultivars. The crude fiber content of Resist Rust King of ryegrass cultivar of animal husbandry type is significantly higher than the other ryegrass cultivars. According to the comparison of crude protein and crude ash are crude fat and crude fiber and phosphorus and calcium of different ryegrass cultivars,the comprehensive nutrition quality of McGrady of ryegrass cultivar of animal husbandry type is better than the other ryegrass cultivars.4. There are obvious genetic differences for the change of chlorophyll content and relative conductivity and malondialdenhyde content and peroxidase activity and proline content of different ryegrass cultivars in different development periods. According to the comparison of changes characteristics of chlorophyll content, relative conductivity, malondialdenhyde content, peroxidase activity and proline content of different ryegrass cultivars in different development periods, there are believed that the order of high temperature resistance of different ryegrass cultivars of lawn type is as follows:Winter Green> Premier> Pandora> Night Shadow Ⅱ> Pinnacle, and the order of high temperature resistance of different ryegrass cultivars of animal husbandry type is as follows:Resist Rust King> Barwoltra> Oregon Tetraploid> Special High> McGrady> Swords> Yaqing.