Abstract: In order to screen out suitable highland barley varieties (Zangqing 2000 and 5171-7) cultivation measures in Lhasa river valley, the split zone test design method was adopted, the main zone had 3 sowing dates (B1, B2, B3), each main zone had 2 highland barley varieties, and each split zone contained 4 levels of fertilization(M, FM, F, CK). The growth period, physiology and biochemistry, photosynthesis and yield composition of highland barley under different treatments were studied. The results showed that short-term fertilization had no significant effect on highland barley production. Timely sowing (B2, 4-15) and delayed sowing (B3, 4-30) increased the length of the highland barley from the seedling to the jointing stage, thus increased the growth period. B3 treatment increased the basic seedlings significantly. Fertilization (M, FM, F) increased the number of stem tillers compared with no fertilizer (CK). B3 treatment could significantly reduced the highland barley plants height by 1.9%-11.2%. The sowing date had the greatest impact on the yield of highland barley, followed by the varieties, and the interaction had the least impact. The sowing date mainly affected the number of panicles, grains per panicle, and thousand-grain weight of highland barley. The differences in the number of panicles and grains per panicle between the two varieties were obviously, Zangqing 2000 had the highest yield under the B2 treatment, while 5171-7 was under the B3 treatment. The timely sowing (B2) or late sowing (B3) increased the photosynthetic rate (Pn) and SPAD of the highland barley at the filling stage, and had higher soluble sugar (SS), soluble protein (SP) and catalase activity (CAT). Compared with Zangqing-2000, the variety 5171-7 had stronger advantages in terms of yield, photosynthetic capacity and Anti-stress. Therefore, selecting 5171-7 and planting at the right time in late April can increase the yield of highland barley in the Lhasa river valley.

Key words: Sowing date, Fertilization, Variety, Highland barley, Photosynthesis, Physiology and biochemistry