Comparison Study On Early Growing Stage Of 22 Alfalfa Cultivars

This paper studied 22 alfalfa (Medicago sativa L.) cultivars which is applying in large area in production, related index of growing characters, yield, quality were measured, yield, quality were focused on to evaluated them synthetically. This research conducted in order to supply high yield, good quality, applicable alfalfa cultivars, to avoid blindness in cultivar choice, to give the element science basis for agriculture production, husbandry developing and prataculture research in Guanzhong and similar area. At the same time this research give a first-hand material of alfalfa cultivar evaluation for breeding researchers.The results as follows:1. 22 alfalfa cultivars had significant difference on growing characters. Most foreign alfalfa cultivars grew fast and were taller than native cultivar Guanzhong alfalfa. Defy, Total, Haygrazer were the tallest of all, and had growing rate more than 1.5-1.8 cm/d, and regrew quickly. Native cultivar Guanzhong alfalfa had lower growing rate, lower height, lower regrowing quality, and lower fall dormancy. In the first year, Guanzhong alfalfa got only 2 cuttings, and foreign alfalfa cultivars can got 3 cuttings.2. 22 alfalfa cultivars had significant difference on total yield and different harvest yield. Victoria, Alfalfa 54 had more green grass yield that was more than 60000kg/hm2. Guanzhong alfalfa had green grass yield of 30800kg/hm2, which is the half of Victoria and Alfalfa 54. Victoria and WL324 had the highest dry grass yield of 15000kg/hm2, which was 2 times of Guanzhong (7333kg/hm2). Foreign cultivars had higher yield either on green grass or dry grass yield than Guanzhong alfalfa.3. 22 alfalfa cultivars had significant difference on quality, total crude protein content and every harvest crude protein content. Crude protein content, crude fiber content were agreement with or higher than international first grade dry grass product standard. Defy, WL323HQ had the crude protein content of 23%. Guanzhong alfalfa had the crude protein of 20.75% and crude fiber content of 16%.4. 22 alfalfa cultivars had insignificant difference on transpiration rate and stomal conduct rate. But photosynthesis rate, inter cellular CO2 concentration, instant water use efficiency (WUE) and canopy temperature were significant. Victoria, WL323ML, WL252HQ had higher instant water use efficiency, WUE of Guanzhong alfalfa was 3 u mol/mol. Hay grazer, Sitel had higher canopy temperature which indicated that they aged quickly. Queen, Amerigraze had lower canopy temperature, which indicated that grass layer had sharp metabolism, higher hot resistance, and aged slowly.5. Evaluated 22 alfalfa cultivars synthetically, Victoria, Total, WL252HQ, Alfalfa 54 had the grades of more than 37.5(total 50 grades). Guanzhong alfalfa had 28.5 grades, (less than 30). Synthetically Application should choose higher grades cultivars. If single destination was chased or uses them as breeding material, only some higher grades index of the cultivars should be chosen, considered them synthetically is not necessary.