NITROGEN-FERTILIZER AND SEEDING DATE INDUCED CHANGES IN PROTEIN, OIL AND BETA-GLUCAN CONTENTS OF 4 OAT CULTIVARS

The application of nitrogen (N) fertilizer at both seeding and the boot stage of plant development (Zadoks 40-43) and/or delayed seeding caused changes in the protein, oil and beta-glucan contents of four oat cultivars in field studies conducted in Quebec Canada, between 1990 and 1992. N fertilizer applied at the boot stage (Zadoks 40-49) tended to increase protein content and to decrease oil content, however, beta-glucan content did not respond significantly to additional N. Generally, delayed seeding increased protein and beta-glucan contents and decreased oil content. In 1992, however, protein and oil contents tended to increase with delayed seeding, while beta-glucan was not affected significantly, although not all cultivars responded in a similar fashion. Environmental conditions during the growing season seemed to influence the effects of delayed seeding on protein, oil and beta-glucan contents because results varied among years. While some cultivar x management treatment interactions were significant, the ranking of the four cultivars was generally consistent across experiments. Thus, if improvement in these characteristics is required, genotype x management interactions should not interfere unduly with the evaluation of late-generation breeding materials for protein, oil and beta-glucan contents.