Research on alfalfa root morphology and health is very important in development of technology for efficient improvement and production of alfalfa. The objectives of this study were to evaluate the root morphology and health of two alfalfa varieties, Algonquin and Golden Queen, to determine relationships among root morphology traits and root health. Results from these analyses indicated t㏊t yield was 6.77-43.93 t/h㎡, total root length ranged from 215.17-708.89 ㎜, root surface area ranged from 93.61-717.06 ㎠, volume ranged from 3.24-57.72㎤. Results from these analyses indicated t㏊t root infestation score was the lowest averaged over age of alfalfa stand in Algonquin. Yield in 2-yr old stands was greater in Golden Queen compared to Algonquin.

In this study, we determinated the dynamic changing of soluble sugar, total nitrogen and malondialdehyde, so t㏊t found out their relationships with cold resistance. The result indicates: the content of soluble sugar and total nitrogen increased from late autumn and early winter, and kept higher level during the entire winter, then decreased in regreen time in the next spring. The content of malondialdehyde was high in Sep., then decreased gradually and reached the minimum in Jan., thereafter the content of malondialdehyde represented increasing trend.