An alysis on dynamic variety of crown characteristics of different fall dormancy Medicago sativa cultivars

For 3 years we studied 4 Medicago sativa cultivars(CW200,Pondus,Grandeur and Victoria),whose fall dormancies are 2,3,4,and 6,respectively.The crown characteristics of the different fall dormancy M.sativa cultivars differed dramatically.The crown depth of the cultivars increased with a decrease of fall dormancy.The maximal velocity of crown depth was from planting time to the first harvest.The crown diameter rapidly increased in the warm summer,as the biomass growth rate reduced.The secondary crowns of fall dormancy cultivars were more numerous and appeared earlier than those of semi-fall dormancy cultivars.The secondary crowns grew in second and third stubble of planting second and subsequent years.Secondary crowns were not produced in the first year or first stubble.The difference of crown diameter and branches between cultivars was significant.Diameters of crowns,numbers and diameters of crown branches were not consistent with the fall dormancy scale.