Yield Response to Cultivar and Sowing Pattern in High‐Yielding Rice

要旨

ABSTRACT Forage rice ( Oryza sativa L.) has attracted attention as a potential crop in Japan, but no optimal agricultural product system has been extensively established. The objective of this study was to determine the effects of cultivar (high‐yielding indica cultivar Hokuriku 193, high‐yielding indica ‐ japonica hybrid cultivar Mizuhochikara, or standard japonica cultivar Akisayaka) and sowing pattern (broadcast or drilling) on grain yield using a new sowing machine for a well‐drained paddy field. Hokuriku 193 had the highest grain yields. Hokuriku 193 and Mizuhochikara had much more spikelets than Akisayaka. Hokuriku 193 and Akisayaka had a higher percentage of filled spikelets than Mizuhochikara. At full heading, Hokuriku 193 had the highest nonstructural carbohydrate (NSC) amount. Thus, the high NSC amount of Hokuriku 193 supported a high grain yield and high percentage of filled spikelets in spite of its very many spikelets. Broadcast gave a higher rough grain yield, grain yield, and number of panicles than that of drilling, but it had no effect on the percentage of filled spikelets or the 1000‐grain weight. At full heading, broadcast gave a higher NSC amount than drilling. Therefore, broadcast of high‐yielding indica or indica ‐ japonica hybrid cultivars might increase grain yield, in spite of its very high panicle number, without decreasing the percentage of filled spikelets or the 1000‐grain weight by increasing the NSC amount at full heading.

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