Abstract
A simple method for predicting the grain protein content (GPC) of spring wheat from plant characters at heading in the field was developed by using the field data for growth diagnosis at Hokkaido Kamikawa Agric. Exp Station and at neighboring farmer’s fields for 3–4 years in Hokkaido, the northern part of Japan. GPC at maturity was strongly correlated with grain yield at plant nitrogen content (PNC) every 2 g m-2 from 8 to 14 g m-2 (r=0.871∼0.937, P\<0.01). The PCN was correlated with “plant height×color value of the second leaf” at heading time (r=0.872, P\<0.01). The grain yield was correlated with “plant height×color value of the second leaf×number of ears” at heading time (r=0.826, P\<0.01). These results indicate that a simple prediction of GPC is possible by using plant characters generally used for growth diagnosis at heading time. This prediction is useful to decide the amount of supplemental application of nitrogen at heading time.
