@article{oai:repository.naro.go.jp:00001649,
 author = {小島, 誠 and KOJIMA, Makoto and 牧, 夏海 and OKAMURA, Natsumi and 岡村, 夏海 and MAKI, Natsumi and 重田, 一人 and SHIGETA, Kazuto and 大下, 泰生 and OSHITA, Yasuo},
 journal = {中央農業総合研究センター研究報告, Bulletin of the National Agricultural Research Center},
 month = {Dec},
 note = {International competitiveness strengthen of farm products is indispensable for Japanese agriculture. So a further cost cut is demanded. Direct seeding of rice as a technique that is effective for a cost reduction. By using the technique, raising of seedling and transplanting, which account for approximately 26% among all rice growing work, become needless. Then this technique is paid attention as the effective technique that can reduce production cost and work force. The dry direct seeding is lower-cost method, but it is influenced by establish habit of seeding and growth properties of cultivars. Therefore we assumed early seeding cultivation and late seeding cultivation as the cropping system that introduction was expected. And we examined establishment of seeding, the growth, yield and quality using ten main paddy-rice cultivars of the Kanto area including some cultivars bred newly in late years  The results are summarized as follows.  1. In case of direct seeding in the end of April, when daily mean temperature was about 15 ℃, final emergence percentage lowered than 50% in many cultivars. When about 250seeds were sown, the number of establishment was more than 50 plans m^-2.  2. In case of early sowing, the days to set of emergency and the days from emergency to heading were longer than that in late sowing. As these reasons that the temperature condition from sowing to emergency was lower and the day length was longer in early sowing than that in late sowing were thought. On the other hand, the days from heading to maturity were longer in late sowing than early sowing. As the main reasons that heading in late sowing began at end of August, then temperature was lowered in the process of seed growth was thought.   3. Comparing yield and yield-related characters between early and late direct seeding cleared that yields in late direct seeding were decreased in many cultivars. Though the effective ear number was not changed, the percentage of ripened grains was decreased was thought as the factor.   4. In yield components, the ranking of number of effective ears and number of spikelets per panicle, percentage of perfect grains were not changed by cropping seasons. In this study, the number of effective ears were increased in late cropping season. But the number of spikelets per panicle and grain filling rate were decreased. The thousand kerneld weight and their ranking between cultivars were not changed by cropping seasons.  5. For getting stable yield in the cropping system of direct seeding in the end of April, using cultivars with much number of the seeds in an ear, because enough temperature is provided during an ear ripening period, is important. And in the cropping system of direct seeding in the middle of June, using cultivars these have much number of the effective ears and these are hard to occur of the green immature grain are important to get stable yields, because it becomes early low temperature condition of the ear ripening process.},
 pages = {1--22},
 title = {異なる作期における水稲品種の乾田直播による収量・品質},
 volume = {26},
 year = {2016},
 yomi = {コジマ, マコト and マキ, ナツミ and オカムラ, ナツミ and シゲタ, カズト and オオシタ, ヤスオ}
}