[[abstract]](1)本試驗為試探利用旱田式病圃淘汰罹病個體之實用價值，初步觀察結果，證明較原採用之水田式病圃方法簡便，又可增加單位面積內栽植個體數，且不受其他氣侯環境等因子之支配，發病容易而均勻。 (2)在本分所病圃內，稻熱病週年均可發病，除了冬季12、1月因氣溫較低不易發病外，其他時期均可誘發嚴重之病害，在雨季若能選擇排水良好場地，設置為病圃，其發病情形亦甚良好。 (3)濕度之保持與本試驗之發病有密切之關係，每日早晚之葉面噴水，亦即生育初期之噴水工作是本試驗誘發病害之最大因素。 (4)水稻生長在旱田與水田狀態，因土壤理化性之不同而使水稻生理機能互異，因此土壤過濕時，雖然葉面上有充分之濕度，亦難使其全面發病。 (5)據試驗結果得知在2月下旬至3月及8月下旬至9月播種者其發病最為嚴重，如能採用世代促進方法再配合此一旱田式病圃法，對本省抗病育種工作，定可收到宏大之效果，而值得其他場所仿效採用。 1. The aim of this experiment was to determine the effectiveness of using non-irrigated nursery for breeding disease resistance of rice in comparison with conventional water-saturated disease nursery. Preliminary results indicated that the non-irrigated nursery was easier to manage and less affected by envi-ronmental factors when compared with the irrigated nursery. The former also had another advantages of allowing a large number of plants to be grown in a limited area, and the blast disease occurrence was also more severe and uniform than the latter. 2. On the Chaiyi Station Farm, the rice blast could be induced year round, except in December and January when the temperature is low. During the rainy season, heavy infection of blast could be obtained in the non-irrigated disease nursery with good drainge. 3. It was found that humidity played an important role in the occurrence of blast fungus. Therefore, spraying water on rice plants both in the morning and aftermoon at the early growth stage of rice is necessary for the induction of the disease. 4. When rice plants were grown in the dry and wet field nursery due to physical and chemical difference in soil conditions, they might differ in the physiological mechanism. Therefore, the rice blast occurred less severely even though sufficient humidity was available on the leave surface. 5. The occurrence of blast disease was found to be more serious when rice was sown from late February to March or from late August to September. If the planting season of rice could be well adjusted to coincide with the above-mentioned time of blast occurrence, it will be very useful for the disease breeding program by making use of the non-irrigated nursery.