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Acta Prataculturae Sinica ›› 2020, Vol. 29 ›› Issue (4): 73-80.DOI: 10.11686/cyxb2019320

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Effect of sowing date on cold resistance of different alfalfa varieties in Horqin sandy land

ZHANG Yu-xia1, WANG Xian-guo2,*, TIAN Yong-lei1, CONG Bai-ming1, WANG Yue-lin3, CHEN Wei-dong1, GAO Kai1   

  1. 1.College of Agriculture, Inner Mongolia University for the Nationalities, Tongliao 028041, China;
    2.College of Animal Science and Technology, China Agricultural University, Beijing 100193, China;
    3.Grassland Station of Inner Mongolia Autonomous Region, Hohhot 010017, China
  • Received:2019-07-16 Revised:2019-10-09 Online:2020-04-20 Published:2020-04-20
  • Contact: E-mail: grasschina@126.com

Abstract: This study investigated the physiological response to sowing date in Horqin sandy land, of metabolites conferring cold-resistance in alfalfa crowns. The research was conducted in Chifeng city, in the Inner Mongolia Autonomous Region, the centre of the grass industry of the AruHorqin district. Three alfalfa varieties (Knight T, Gongnong No.1 and Optimus) were selected and sown every five days from July 1, 2017 to August 15. The contents of soluble sugar, soluble protein, free amino acid and starch in alfalfa crowns were determined and sampling on October 11 and November 11, 2017, and the overwinter survival rate was evaluated in spring of the second year. The changes in the content of metabolites conferring cold-resistance in alfalfa crowns and their correlation with the overwinter survival rate were explored. It was found that the soluble sugar, soluble protein, starch and free amino acid levels in alfalfa crowns were decreased by later sowing time. The overwinter survival rate of alfalfa was positively correlated with soluble sugars, soluble proteins and free amino acids in alfalfa crowns sampled on November 11. The overwinter survival rate of alfalfa was positively correlated with the content of soluble sugar in alfalfa crowns sampled on October 11, and significantly positively correlated with soluble protein and free amino acid concentrations. The concentrations of soluble sugar and starch in crowns of alfalfa cultivar Gongnong No.1 was significantly higher than those of alfalfa cultivars Knight T and Optimus on November 11, and this observation is consistent with cultivar differences in overwintering survival rate. It is considered that sowing date is one of the important factors affecting the overwintering of alfalfa in Horqin sandy land. Soluble sugar, soluble protein and free amino acids in alfalfa crowns are metabolites conferring cold-resistance. In order to ensure safe overwintering of alfalfa in the Horqin sandy land, the ideal sowing period was from July 1st to July 16th, and the cultivar best suited to this area was Gongnong No.1.

Key words: alfalfa, sowing time, cold-resistant protective substances, overwintering rate