Nitrogen Content, Oil Content and Oil Composition of Oat Cultivars (A. sativa) and WildAvenaSpecies in Relation to Nitrogen Fertility, Yield and Partitioning of Assimilates

Three European and three North American oat cultivars (Avena sativa) and 10 wild Avena species were grown to maturity in pots at three nitrogen fertility levels. The yield and nitrogen content of plant parts, and the production and partitioning of dry matter and nitrogen were measured. Groats were also analysed for oil content and composition. Some wild species had high groat oil (12-13%). Groat nitrogen was higher in wild species (2.9-6.3%) than cultivars (1.5-2.7%). Increases in total yield and total nitrogen yield closely corresponded with increases in nitrogen fertility level. Two wild species, with groat nitrogen contents significantly greater than those of all the cultivars at all fertility levels (A. maroccana, A. canariensis), also had total plant dry matter yields and total plant nitrogen yields that were not significantly different from those of a number of cultivars. The hull contributed substantially to dry matter and nitrogen yield in some wild species, and in two (A. canariensis, A. maroccana) partitioning of both dry matter and nitrogen to the grain was not significantly different from those for most cultivars. There were significant genotype x fertility interactions for a number of characteristics, but there was no evidence that wild species had superior nitrogen economies at any fertility level. In a comparison of cultivars, however, variation in groat nitrogen content was associated with variation in nitrogen partitioning.