The Distribution of Protein and Non-structural Carbohydrate in Five Oat Varieties during Plant Growth and Grain Development

Abstract

Two European and three North American spring oat varieties, selected for their variation in grain protein percentage, were grown in a field experiment. Plants were sampled at regular intervals during growth and development, separated into grain and straw where appropriate, and analysed for protein and non-structural carbohydrate. Grain protein content increased throughout grain filling and varietal differences were apparent during development and at maturity. Grain non-structural carbohydrate also increased during development but varietal differences were distinct only at maturity when the high-protein varieties were lower in grain non-structural carbohydrate. The ratio of protein to non-structural carbohydrate in the grain was higher in the high protein varieties throughout most of the grain filling period and at maturity but there were no varietal differences in total protein plus non-structural carbohydrate per grain. The protein and carbohydrate contents of the straw declined during grain filling and although there was varietal variation in the rate and degree of loss which may be associated with grain protein content, there was no indication that high protein was associated with a reduction in carbohydrate remobilisation.