| In order to explore the effect of choline chloride on yield and quality of alfalfa in seasonal cultivation system in southern China, a field experiment was conducted on Shanghai Chongming Island from September2011to July2012. A less fall dormancy alfalfa cultivar sanditi was used to study the effect of different concentrations of choline chloride(0、200、400、600、800、1000mg/L)on growth characteristics, photo synthetic characteristics, yield and quality of alfalfa. The results showed as follows:1.Choline chloride improved shoot growth of alfalfa. There were different effects on alfalfa because of different concentrations of choline chloride. The plant height increased significantly (P<0.05) at600mg/L when compared with control, and the stem diameter, single stem weight, shoot number and plant height of alfalfa reached the maximum at600mg/L at first harvest time, but the plant leaf area reached maximum at400mg/L. At second harvest time, the stem diameter and single stem weight of alfalfa were significantly higher (P<0.05) than control and reached maximum at400mg/L, while the shoot number and leaf area per plant were significantly higher (P<0.05) than control and reached maximum at600mg/L. Plant height was highest at400mg/L.2. Choline chloride enhanced the chlorophyll content and photosynthetic performance of alfalfa. Chlorophyll content increased at different concentrations of choline chloride compared with control and reached maximum at600mg/L in both first and second harvest time. Chlorophyll content was significantly higher (P<0.05) than control at the treatment of400mg/L and600mg/L at first harvest, while there were no significant difference with control at second harvest. Pn was higher than control at different level except at200mg/L at first harvest, meanwhile the choline chloride content was significant higher (P<0.05) than control at the level of400mg/L,600mg/L and800mg/L. Pn reached the maximum at600mg/L and was higher significantly than that at200mg/L and1000mg/L. At second harvest, Pn in all treatments with spraying choline chloride were higher than control but had no significant difference. Pn reached the maximum at400mg/L3. Choline chloride promoted the transport of photosynthate to the root and increased the NSC content in root of alfalfa and boosted the early regrowth of alfalfa. The NSC content under different level of choline chloride concentration was higher than control. With the increasing concentration of choline chloride, the contents of starch and soluble carbohydrate were increased first and then decreased. The content of starch reached highest in root at400mg/L, while that of soluble carbohydrate at600mg/L. In summary, the content of NSC reached high level at400mg/L and600mg/L and later was higher (P<0.05) than control. There were no significant difference (P>0.05) among different treatments of choline chloride concentration.4. Choline chloride significantly increased the DM yield at each harvest time. At the first harvest time, DM yield of treatments with600mg/L and400mg/L were significantly higher than that of control (P<0.05), and the highest DM yield was obtained at600mg/L. DM yield of all treatments with spraying choline chloride were also higher than that of control at the second harvest time, but there wasn’t significant difference within all treatments (P>0.05). The total DM yield including two harvests showed the same trend as the first cutting time but with the highest DM yield under the treatment of400mg/L.5. Choline chloride improved forage quality of alfalfa. The best quality was obtained at600mg/L, which was significant higher than control (P<0.05). At each harvest time, the content of crude protein was highest at600mg/L, with19.95%at the first harvest time and15.27%at the second, respectively, whereas the content of NDF and ADF were lowest leading to higher IVDMD.In conclusion, choline chloride improved shoot growth and increase DM yield by increasing plant height, stem diameter, shoot number, single stem weight and leaf area per plant. Choline chloride also increased chlorophyll content, photosynthesis, promote the transport of photosynthate to root and boost the early regrowth of alfalfa. In addition, choline chloride increased CP content and IVDMD effectively, whereas decreased the content of NDF and ADF, which contribute to the better forage quality of alfalfa. There were significant influence on DM and forage quality at the level of400mg/L and600mg/L This study can provide theoretical basis for improving the yield and forage quality of alfalfa in seasonal cultivation, and promote the growth and development of alfalfa in south China. |
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