초록
$Indica{\times}Japonica$형(型) 수도품종(水稻品種)의 저온발아성(低溫發芽性)과 유묘기(幼苗期)의 저온(低溫)에 의(依)한 장해(障害)를 구명(究明)하기 위(爲)하여 유일외(流一外)29개(個)의 품종(品種)을 $10^{\circ}C$ 및 $15^{\circ}C$ 등(等)에서 발아시험(發芽試驗)하는 한편 유일외(流一外)5개(個) 품종(品種)을 15일간(日間) pot하여 재배(栽培)하여 $5^{\circ}C$ 및 $15^{\circ}C$에서 각각처리(各各處理)한 15 일(日) 후(後)에 모의 생육(生育) 조사(調査)하였던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. $10^{\circ}C$에서는 이리(裡里) 323호(號), (水原) 253호(號), 이리(裡里) 325호(號), 밀양(密陽) 22호(號), 수원(水原) 251호(號) 및 수원(水原) 267호(號)등 품종(品種)은 70% 이상(以上)의 발아율(發芽率)을 보였고, 도도로끼와세, 밀양(密陽) 23호(號), 유신(維新), 이리(裡里) 328호(號) 및 이리(裡里) 329호(號)등 품종(品種)은 10% 이하(以下)의 낮은 발아율(發芽率)을 보였다. 2. $15^{\circ}C$에서는 수원(水原) 262호(號)는 100%의 발아율(發芽率)을 보였으며, 밀양(密陽) 22호(號), 도도로끼와세, 유일(流一), 밀양(密陽) 29호(號) 수원(水原) 258호(號), 밀양(密陽) 23호(號), 밀양(密陽) 24호(號), 밀양(密陽) 28호(號) 및 밀양(密陽) 21호(號)등 품종(品種)은 90% 이상(以上)의 높은 발아율(發芽率)을 보였던 반면(反面) 이리(裡里) 328호(號), 이리(裡里) 329호(號), 진흥(振興) 및 미네히까리 등 품종(品種)은 50% 이하(以下)의 낮은 발아율(發芽率)을 보였다. 3. 발아율(發芽率)과 평균발아(平均發芽) 일수(日數)를 감안(勘案)할 때 밀양(密陽)22호(號) 및 이리(裡里) 323호(號)가 저온발아성(低溫發芽性)이 높은 품종(品種)이라고 보겠으며 $Indica{\times}Japonica$형(型) 품종(品種)의 저온아성(低溫芽性) 정도(程度)는 Japonica형(型) 품종(品種)들에 비(比)해 반드시 낮지 않았다. 4. $1^{\circ}C$에서 유묘(幼苗)가 6시간(時間)은 노출(露出)되어 있어도 생육(生育)에 거의 영향(影響)을 받지 않았으며 12시간(時間) 노출(露出)되었을 경우(境遇) 품종(品種)에 따라 잎이 시드는 경향(傾向)을 보였으나 다시 정당온도(正堂溫度)를 유지(維持)할 경우(境遇) 회복(回復)되었다. 유묘(幼苗)가 저온(低溫)에 노출(露出)되었을 경우(境遇) 잎이 시드는 정도(程度)는 Japonica형(型) 품종(品種)인 밀양(密陽) 15호(號)가 $Indica{\times}Japonica$형(型) 품종군(品種群)에 비(比)현저(顯著)히 낮았다. 5. 조생유일(早生幼一), 유일(幼一) 및 유신(維新)의 유묘(幼苗)는 $1^{\circ}C$에서 36시간(時間) 처리(處理)되었을 경우(境遇) 70% 그리고 72시간(時間) 처리(處理)에서는 100% 고사(枯死)하였으며 약온처리(藥溫處理)에서도 75% 이상(以上) 고사(枯死)하였던 반면(反面) 밀양(密陽) 15호(號)는 72시간(時間) 처리(處理)되었을 경우(境遇) 65%의 고사율(枯死率)을 보였다. 6. 공시(供試)된 전체품종(全體品種)은 24시간(時間) 내지 36시간(時間) 처리(處理)에서 지상부(地上部) 및 지하부(地下部) 생육(生育)의 현저(顯著)한 감퇴(減退)를 보였고 감퇴정도(減退程度)는 처리시간(處理時間)이 길어짐에 따라 현저(顯著)히 심(甚)하였다.
An expriment was conducted to determine the rate of germination under low temperature and effects of low temperature on seedling of varieties derived from the cross between Indica and Japonica type of rice. Total of 30 varieties including leading variety, Tongil, were germinated at the temperature of $10^{\circ}C$. and $15^{\circ}C$. to determine the rate of germination, and six varieties also including Tongil were planted in pot, and seedlings were exposed to the temperature of $5^{\circ}C$. and $1^{\circ}C$. for 15 days and damage of plant growth due to low temperature was observed. 1. Under the condition of $10^{\circ}C$., varieties such as Iri #323, Suwon #253, Iri #325, Milyang #22, Suwon #251, and Suwon #267 were showing over 70 percent of germination ratio, while varieties, Dodolokiwase, Milyang #23, Yusin, Iri #328, and Iri #329 were below 10 percent in germination ratio. 2. Under the condition of $15^{\circ}C$., variety Suwon #262 was shown 100 percent of germination and varieties such as Milyg an#22, Dodlokiwase, Tongil, Milyang #29, Suwon #258, Milyang #23, Milyang #24, Milyang #28 and Milyang #21 were over 90 percent in germination ratio. However, varieties such as Iri #328, Iri #329, Jinheung, and Minehikari were below 50 percent in germination rate. 3. Considering the germination rate and average days required to germination, Milyang #22 and Iri #323 were highly resistant varieties to low temperature. The rate of germination of varieties from the cross between Indica and Japonica under low temperature was not always lower than that of varieties from Japonica type of rice. 4. Most of the seedlings of varieties used were quite resistant to $1^{\circ}C$. at least for six hours. However, leaves of rice were exposed to the the temperature of $1^{\circ}C$. for 12 hours, and the withered leaves were recovered soon when put in under normal temperature. The degree of leaf withering under low temperature was lower in Milyang #15, Japonica type than in varietieties belonging to $Indica{\times}Japonica$ type of rice. 5. When the seedlings of varieties such as Josaengtongil, Tongil and Yusin were exposed to the temperature of $1^{\circ}C$. for 36 hours, 70 percent of leaves were withered and when the time of expose were doubled, the leaves were completely died. When the temperature was fluctuated, over 75 percent of leaves were died, while 65 percent of leaves of Milyang #15 were died when exposed to $1^{\circ}C$, for 72 hours. 6. Significant growth retardation was observed for all entries when exposed to $1^{\circ}C$. for 24 to 36 hours. The growth retardation was apparently increased as the time of expose was extended.