The response of some barley varieties to irrigation and nitrogen fertilizer

Summary Four varieties of barley, selected for characteristics which could have value in a barley variety intended primarily for animal food, were compared with the variety Proctor under two levels of irrigation and two levels of nitrogen fertilizer. The exotic varieties yielded less grain and total dry matter than the adapted varieties, but differed in their response to irrigation. This difference was due chiefly to the ability to form extra ears when irrigated and the other yield components were less affected. Nitrogen fertilizer did not affect yield, although more ears were formed in the highlevel than the low-level treatment. The yield of nitrogen in the whole plant and in the yield of grain nitrogen were increased by high-nitrogen fertilizer and one of the exotic varieties was found to be capable of high yields of both grain nitrogen and total nitrogen, but there were no varietal differences in the response to nitrogen fertilizer. The varietal differences in response to irrigation are briefly discussed and related to development and possible drought resistance. The nitrogen yield of the grain is analysed in terms of total nitrogen uptake and distribution within the plant and the possibility of using the variation in these characteristics in a breeding programme is raised.