行政院農業委員會台南區農業改良場  研究彙報第8號

水稻臺南五號種子處理對休眠性影響試驗

林德裕 鄭義雄 邱倚星

摘  要

臺南五號為目前本省栽培最廣之品種,其新鮮稻種具有短期之休眠性,而使早植部份因採用貯藏時間較短之種子而發芽率低,秧苗生長不齊之現象,導致育苗失敗。本試驗即為探究該品種種子處理方法,對休眠性之影響,期能查出適宜之處理方法,以解決因休眠性所產生之問題。試驗分三部份於民國六十年及六十一年第二期作在嘉義分場進行,其結果摘錄如次:

(一)試驗一種子貯藏期間與浸種時期對休眠性之影響試驗係於民國六十年及六十一年第二期作採用裂區設計,四重複,以種子貯藏期間為主區,浸種期間為副區,催芽期間為副區,其結果顯示,採用臺南五號新鮮稻種,在第二期作高溫情形下育苗為求85%以上之發芽率時,如採用僅貯藏5天以內之新鮮稻種必需浸種4天,催芽2天,如採用貯藏10天之稻種則需浸種3天,催芽2天,或浸種4天,催芽1天,如採用貯藏15天之稻種則只要浸種3天,催芽1天,採用貯藏20天以上之稻種則只要浸種2天,催芽1天即可。至於本試驗各處理在秧田調查結果亦顯示,隨著貯藏期,浸種期之增加,其發芽率亦佳,催芽2天與1天之秧苗則未見有明顯之差異,但依發芽勢而論,則催芽2天者初期似比僅催芽1天者較為整齊一致。

(二)試驗二溫湯處理與硝酸液處理對休眠性之影響試驗採用隨機區集設計,四重複,分為無處理,50℃溫湯處理,70℃溫湯處理及0.0042%硝酸液處理等四種處理,並分別在室內及室外進行,其結果顯示,發芽率以50℃溫湯處理及0.0042%硝酸液處理者均達80%以上,而未處理者發芽率僅47%,而70℃溫液處理因溫度過高,全部不發芽,可見臺南五號新鮮稻種仍需有妥當之處理才能獲得良好之發芽率。

(三)試驗三不同開花後日數(成熟度)與種子含水量,種子溫湯或硝酸液處理對休眠性影響試驗,採用二重裂區設計,四重複,成熟度為主區,含水量為副區,各種處理方法為副副區,其結果顯示,成熟度越高發芽率越高,稻種晒得越乾,發芽率也愈高。成熟度28天者需晒至含水量10%,並用0.0042%硝酸液處理始能獲得良好之發芽率。成熟度32天及36天之稻種只要採用50℃溫湯或0.0042%硝酸液處理者,其含水量在16%以下均能有80%以上之發芽。


Test of Seed Treatment to Break Seed Dormancy of the Rice Variety Tainan 5

D.Y.Lin, Y. H. Cheng and Y. H. Chiou

Summary

       Tainan 5 is the topmost leading rice variety in Taiwan and its planted acreage was more than 300,000 ha in 1969.  This variety, however, often shows poor germination in seedling nursery of the second crop, especially when fresh seeds of the first crop are directly used. This phenomenon is presumed to be the cause of the short duration of seed dormancy.  The proposed study is to investigate the effects of different methods of seed treatment so as to solve the seed dormancy problem, this experiment includes three parts:

Experiment 1: The effect of seed storage and soaking time on the expression of seed dormancy.

Experiment 2: The effect of hot water and nitric solution treatment on the expression of seed dormancy.

Experiment 3: The effect of seed maturity and water contents on the expression of seed dormancy.

       The results obtained are summarized as follow:

Experiment 1:

       In order to gain a more than 85% of seed germination, the result of this experiment indicated that the following treatment is necessary.

1. When use the fresh seeds with less than 5 days storage, it needs 4 days soaking and 2 days pre-sprouting treatment.

2. When use the seeds of 10 days storage, it needs 3 days soaking and 1 day pre-sprouting treatment or 4 days soaking and 1 day pre-sprouting treatment.

3. If the storage duration is 15 days, it needs 3 days soaking and 1 day pre-sprouting treatment.

4. If the storage duration is longer than 20 days, it only needs 2 days soaking and 1 day pre-sprouting treatment.

Experiment 2:

       Both 50℃ hot water treatment and 0.0042% nitric solution treatment all got more than 80% of germination, but the seeds with no treatment only has 47% of germination, indicating that it is necessary to have some treatments before sowing for having a good germination when adopt the fresh seeds of Tainan 5.

Experiment 3:

       The result shows that the longer maturity the higher percentage of germination the water content of seeds shows the same tendency, the dryer of seed the higher percentage of germination. For to get a good germination the seed of 28 days maturity (from heading to harvest) needs a drying of lower than 10% water contents and use the 0.0042% of nitric solution to treat it.  The 32 days and 36 days of maturity of seeds if treated by 50℃ hot water or 0.0042% of nitric solution even use the seeds that content 16% of water still have a good germination more than 80%.



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