EFFECTS OF NITROGEN AND THE PLANT-GROWTH REGULATOR CHLORMEQUAT ON GRAIN-SIZE, NITROGEN-CONTENT AND AMINO-ACID-COMPOSITION OF TRITICALE

Field experiments were conducted in Scotland between 1985 and 1987 to examine the responses of mean grain weight and nitrogen content of triticale cultivars to levels of applied nitrogen from 0 to 180 kg N/ha and the plant growth regulator chlormequat. Cultivar differences were seen for both these characters. Mean grain weight generally declined as yield increased, whether with nitrogen or with chlormequat. Nitrogen content of the grain decreased as grain size increased. Nitrogen recovery (g/m2) generally increased with applied nitrogen and was unaffected by chlormequat application. Within a grain sample from an individual treatment, however, grain size was not related to nitrogen content. The response of nitrogen content is interpreted as differential dilution of nitrogen in the grain by different amounts of carbohydrate. This is probably related to the frequent occurrence of shrivelled grain in triticale.