Characteristics of growth and yield of Japanese high-yielding rice [Oryza sativa] varieties cultivated in the Shikoku area [Japan]
1997
Nagata, K. (Shikoku National Agricultural Experiment Station, Zentsuji, Kagawa (Japan)) | Yoshinaga, S. | Kobayashi, H. | Takanashi, J.
We carried out field experiments to examine the growth and yield performance of high-yielding rice varieties which were newly bred in Japan. Based on the data collected during the field experiments, we also analyzed some of the factors controlling high grain yield in rice in the shikoku area. Results obtained were as follows. (1) Lines "Saikai 198", "Saikai 203" and variety "Takanari" showed a high grain yield performance above 900 g/square-meter, which largely surpassed our target yield. Maximum grain yield was 1035 g/square-meter, which was attained by "Saikai 198" in 1994. These lines and variety were characterized by a longer growth duration, larger dry weight of plant, shorter plant height, larger number of spikelets per panicle and larger number of square-meter spikelets, compared with the standard Japanese variety "Nipponbare". (2) Early season transplanting cultivation showed a higher grain yield performance compared with ordinary season transplanting cultivation. However some of the varieties grown under ordinary season transplanting cultivation showed a high value for the time efficiency of grain yield production which was comparable to that in early season transplanting cultivation. These characteristics seemed to be suitable for short term cultivation which is often practiced in rotational rice cultivation with barley or vegetables in this area. (3) Based on the analysis of the relationships between grain yield and yield components, it was demonstrated that the increase in grain yield by high-yielding rice could be largely attained by increasing the grain number on a square-meter land basis. However, higher level of grain yield above 900 g/square-meter was mainly contributed by the ripening grade
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