| Cultivar and environmental effects on germinating performance and some quality characters were studied by using the two barley cultivars (92-11 and Xiumai-3). The main results are as follows:There was a significant difference in germinating performance between two cultivars, being Xiumai-3 superior to 92-11. Within an ear, grains located at the top position showed the fastest germination, the middle grains were the second and the bottom grains were the slowest. The variation in germination among the grains located at the different ear positions was also affected by N application, ears per area as well as source-sink ratio and two cultivars differed significantly in their response to these treatments.Top grains contained higher & -amylase activity in comparion with other positioned grains. Application of N fertilizer at booting stage (N3) or more ears per area (120 ears per fine) caused dramatic increase in B -amylase activity of both middle- and bottom-positioned grains, leading to smaller difference among grains within an ear. However the variation of & -amylase activity among grains within an ear caused by source-sink ratio treatment was dependent on cultivar. There was the significant difference in protein content among differently-positioned grains at an ear and N application treatments showed the marked effect on protein content, being the same tendency for two cultivars, i.e. N3>N2>N1. Heavy application of N fertilizer at booting stage (N3) inclined to have grain protein content higher beyond the upper limit for malting. In addition, N3 treatment also enlarged the variation in protein content among grains within an ear. In this study the variation in grain weight within an ear was also examined. The results showed that middle grains had the highest grain weight and top grains had the lowest. Removing of middle-positioned kernels could improve significantly grain weight of top-fxnifonfd grains. Removing of flag teqf n玼H*d in reduced grain weight both in middle-positioned and bottom-positioned grains.As to the relation between germinating performance and some other grain qualities, it was showed that lower grain weight or higher P -amylase activity could accelerate the time of germination. The faster germination of topgrains was partly attributed to lower grain weight and higher P -amylase activity. Slower germination of cultivar 92-11 than Xiumai-3 could be relevant to its higher grain weight and higher protein content which may inhibit P -amylase activity.There were the significant differences in P -amylase activity, protein content and grain weight between two cultivars used in this study, 92-11 being significantly higher than Xiumai-3. P -amylase activity was higher under higher ear population, while other three quality traits had less response to planting density. N application at booting stage (N2 and N3), increased significantly P -amylase activity and protein content. Under the condition of more N application at booting stage (N3), grain weight became smaller, which was partly due to the compensation among yield components. P-glucan content was the highest at the treatment of N2, in which the equal amount of N was top-dres*ed at tillering and booting stage.The yield of 92-11 was higher than that of Xiumai-3. In terms of yield formation, Xiumai-3 was more sensitive to planting density than 92-11 and 92-11 was more sensitive to N application timing than Xiumai-3. The yield reduced at lower planting density, which was mainly due to fewer final ears because of lower density. N application timing affected dramatically yield, N1 (with more N application at tillering stage) treatment had the highest yield, while N3 (with more N application at booting stage) the lowest. |
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