Cereal Chem. 73 (5):571-573  |  VIEW ARTICLE

Nonwheat Grains and Products

Effect of N Top-Dressing on Protein Content in Japonica and Indica Rice Grains.

Nazrul Islam, S. Inanaga, N. Chishaki, and T. Horiguchi (1). (1) Laboratory of Fertilizer and Plant Nutrition, Faculty of Agriculture, Kagoshima University, Kagoshima, 890 Japan. Fax 099-285-8665. E-mail: <hiryo@env.agri.kagoshima-u.ac.jp> Accepted June 13, 1996. Copyright 1996 by the American Association of Cereal Chemists, Inc. 

The accumulation and distribution of (^15)N in the protein and protein fractions of rice grains were investigated by N topdressing at three stages: panicle initiation, heading (HD), and HD+20 days. A traditional tall indica and a semidwarf japonica rice variety treated with two levels of basal N were used for the investigation. Topdressing of N increased crude protein and each protein fraction in the grain. The amount of increase was considerably greater in the indica than in the japonica variety. The top-dressed (^15)N partitioned most effectively to the glutelin fraction when it was applied at the HD stage. On the other hand, (^15)N applied at HD+20 days contributed more to increased prolamin. Topdressing of N was effective in obtaining rice grains with high quality protein (high glutelin content) in the indica variety, especially when N was top-dressed at HD and HD+20 days.