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(27(3):213-222)Rice yielding increases for the second crop in Taiwan - Genotype-season interaction and correlation between yields of the first and second crop
No full text以1971年2期至1975年1期之蓬萊稻區域試驗及1973年1期至1976年2期之秈稻區域試驗資料分析結果，蓬萊稻一期作以中南部產量最高，公頃平均產量在6噸以上。二期作以屏東減產最明顯，中部地區一、二期差異最少。秈稻的產量比梗稻高，唯北部地區二期作有明顯減產現象。一、二期稻作產量大部分地點呈正相關，少部分地點呈負相關但不顯著。各地區產量變方分析的結果，大部分地點均只期作間的差異達顯著水準。地點合併分析，結果蓬萊稻部分僅期作間的差異達1%的顯著水準，秈稻方面，品種間與期作間的差異均達1%的顯著水準。
The data of regional yield trials from 1971-II to 1975-I of Japonica rice and from 1973 I to 1976-11 of Indica rice were used for studying genotype-season interaction and the correlation between yields of the first and second crop. For the most cases, it was found that the yields of the first crop and second crop were positively correlated. A few cases with negative correlation coefficient were obtained, but they were too small to be significant at 5% of probability. Variance analyses for the grain yields showed only the differences between seasons were significant at 5% of probability. Combined analyses for the different localities showed that significant differences for seasons were found for Japonica rice as well as for Indica rice, however, only Indica rice revealed the varietal differences at 1% of probaility
(20(3):1-11)EFFECTS OF SELECTION IN TWO HYBRID POPULATIONS OF RICE PROPAGATED IN DIFFERENT CROP SEASONS I. SELECTION IN EARLY SEGREGATING GENERATIONS
No full text本研究以農林48號 × 臺中在來1號及嘉農242號 × Rizzotto二組合，就其雜交後裔各分為一期作選育、二期作選育及一、二期作連續選育三種處理，分別自F2代開始分期選拔，迨至F6代始分期選拔二部份進行，以探求雜交後代分期選育之效果，及早期世代分期與後期世代始分期選育之差異。試驗自52年開始，至F4代與一、二期連續選育者比較分期處理主要農藝性狀之變異，至F5世代比較分期與連續選育處理之差異，並按組合各處理選拔21系統，3處理共63系統，加對照種共64種，以簡方設計分別在一期作及二期作環境進行蠻量試驗，此為早期世代開始分期選育部份。玆將結果摘要列下：
1. 分期選育處理，每年繁殖一代，一、二期連續選育處理，須停止一年予以配合。至F4代分期與連續選育處理之比較，在一期作環境。農林48號 × 臺中在來1號及嘉農242號 × Rizzotto組合，分期選育之處理，均為生育日數稍長，穩長、穗重較優異，一叢穗重較大。在二期作環境，二個雜交組合之結果仍為相似，分期選育之處理，有效分蘗稍多，穗長反略減少，但結實較佳，一叢穗重仍較優異。
2. F5代分期與一、二期連續選育之系統，在一期作環境試驗，其一叢穗重之分佈，農林48號 × 臺中在來1號組合，為一、二期連續選育者絞優異，平均值較大。嘉農242號 × Rizzotto組合，一叢穗重之分佈，則為分期選育者較優，平均值較大。在二期作試驗，二個雜交組合，其一叢穗重之分佈，均為分期選育者較優異，而平均值較大。
3. 由F5代之二個組合，各按三種處理選育之品系，聯合於一期作及二期作環境進行產量試驗，在一期作結果，不論農林48號 × 臺中在來1號或嘉農242號 × Rizzotto組合，各處理選育品系間之產量，經變方分析，均有顯著差異。由各品系蠻量之分佈觀察，農林48號×臺中在來1號組合以一、二期連續選育處理最優異，平均產量最高，與分期選育者差異顯著。嘉農242號 × Rizzotto組合則以一期作選育處理之平均產量最高，一、二期連續選育處理最差，但三處理之相互間差異均不顯著。二期作結果，仍與一期作相似。
Dur to different climatic conditions in the first (Spring) and the second (Fell) crop seasons of rice in Taiwan, the strains selected consecutively in different seasons may bring about higher adaptability to different seasons. To test this idea, the segregating hybrid populations of two crosses of rice, Nohrin 48 X Taichung (Native) 1 and Chianung 242 X Rizzotto, were separately grown, up to F5 generation, in three different consecutive seasons, i.e., the first crop seasons only, the second crop seasons only and both crop seasons consecutively. Each of the three bulk populations from the each cross contained about 1,500, 10,000 and 5,000 indivduals respectively in the F2, F3 and F4 generation. Artificial selection was practiced in the F4 based on the performance of individual plants and 80 lines per bulk-population were grown in the F5. In the F4 as well as in the F5, the first-crop populations were compared with the both-crop populations regarding their major agronomic characters in the first crop seasons and the second-crop populations were compared with them in the second crop. In the F5, 21 lines were selected from each bulk-population to form strains for yield trals in the F6. A total of 63 strains from each cross ere yield-tested with one check variety in both crop seasons. A simple lattice design with two replications was used in the trials. The results were summarized below.
1. The first-crop populations in the F4 of both crosses showed a longer duration from transplanting to heading heavier panicle weight, more panicles per individual plant in average, than those of the both-crop populations. The second-crop populations revealed more panicles per individual higher percentage of fertility, heavier panicle weight, and shorter panicle length than those of the both-crop populations.
2. In the F5 of Nohrin 48 X Taichung (Native) 1, the selected lines from first-crop populations showed more panicles per hill and shorter panicle length in the first crop than those from the both-crop populations, while a reversed result was found in the cross-combination of Chainung 242 X Rizzotto. In the second crop, the lines selected from the second-crop population performed shorter growth duration, heavier panicle weight per hill than those from the both-crop populations.
3. In the F6 generation, the selected lines from the both-crop populations showed the highest grain yield in either crop seasnos when the cross of Nohrin 48 X Taichung Native 1 was concerned. It seems that the both-crop selection gave the highest selection effect in this cross crobination. However, no such significant diference has been found in the populations derived from the hybrid of another cross, Chianung 242 X Rizzotto
(34(2):145-156)Cold Tolerance of Rice at Seeding Stage. II. Effects of Air Temperatures Before and After Chilling Treatment on Cold Tolerance
No full text以新竹矮腳尖、新竹糯4 號、臺農不秈育2414、IR30、IR29、PIl62319、USSR No.45、Pratao 等8 品種的秧苗達3.5-4 葉齡時，以日夜溫10℃ 處理9 天，處理前後分別以30 / 25℃ 及20 / 15℃ 培育秧苗，共2 × 2 = 4 處理，採複因子完全逢機設計，重複10 次，生長箱之光照強度為270 uEm-2 Sec-1光照時間為每天12 小時，探討秧苗生長期之溫度對其耐寒性之影響，結果發現：高溫之前處理雖能促進秧苗之伸長，但其伸長勢與耐寒性無關，低溫處理前後之溫度顯著地影響低溫處理之結果，低溫處理前以30 / 25℃ 培育時，較易顯出耐寒性之品種間差異，且各品種之平均存活率較低，葉片滲出液之導電度與秧苗存活率呈顯著的負相關。在低溫處理的第3 或6 天以後，所測之葉片導電度可反應該品種之耐寒性。鮮葉重受低溫處理影響顯著。且與存活率呈正相關關係。表示低溫處理後測得之葉片滲出液導電度與鮮葉重可供測驗水稻苗期耐寒性指標之一。
Eight rice varieties were used as experimental materials to study the effects of air temperatures (30/25°C or 20/15°C) before and after low temperature treatment (10/10°C) on the cold tolerance of rice seedlings. The duration for pre- and post-low temperature treatment was 1 and 2 weeks, respectively. Seedlings at 3.5-4 leaf age were subjected to 10°C of low temperature treatment for 9 days. The light intensity was 270 uEm-2 Sec-1 for 12 hrs per day in the growth chabmers.
The air temperatures before and after the low temperature treatment did affect the growth rate of rice seedlings in terms of seedling height. In general, seedlings under higher temperature at pre-treatment stage showed higher growth rate and the rate was maintained throughout the low temperature treatment period. Seedlings under lower temperature at pre-treatment stage, however, tended to have higher growth rate at the post treatment stage.
Results also showed that the treatment of 10°C for 9 days was adequate to reveal the varietal differences in conductivity of cell leakage, especially for pre- 30/25°C treatment to show a higher and wider range of conductivity. A similar result was also obtained on fresh leaf weight.
Based on the data of survival rate, which were read two weeks after low temperature treatment, rice seedlings under high temperature (30/25°C) at the pre-treatment stage tended to have lower survival rate for semi-cold tolerant and cold sensitive varieties, especially with the low temperature (20/15°C) at post-treatment stage. However, rice seedlings under pre-30/25°C and post-20/15°C treatment showed the highest survival rate among the 4 treatments. In addition, the result from variance analysis revealed that the variety × treatment interaction reached the 1% significant level. Cold tolerant varieties such as HCW 4 and USSR No. 45 had little variation under different treatments. The semi-cold-tolerant varieties and cold sensitive varieties, however, had a relatively low survival rate if the air temperature at the pre-treatment satage was high, but the survival rate was higher if the air temperature at the pre-treatment stage was low.
Regression analysis between conductivity of cell leakge and survival rate, and fresh leaf weight and survival rate indicated that both conductivity of cell leakage and fresh leaf weight, measured at the 9th day of low temperature treatment, can be used as indicators for screening the cold tolerant rice varieties at seedling stage
(28(1):1-6)Breeding and genetic studies for the resistance to bacterial leaf blight disease in indica rice III. on the relationship between the resistance to bacterial leaf blight disease and cold tolerance
No full text利用抗白葉枯病耐寒之Pl 162319 ，分別與感病不耐寒之嘉農秈11 號與嘉農秈育12 號等品種雜交，由其F2及F3 後裔，分別測定其耐寒性及對白葉枯病之反應，以探討控制該兩性狀之遺傳因子是否有相關關係存在，以供育成抗病、耐寒及豐產品種之參考。試驗結果得知F2 族群中抗白葉枯病個體出現之頻度，不因供試材料經低溫處理而顯著的減少或增加。又由F3 後裔檢驗之結果得知，供試兩組合之抗病與耐寒性間之簡單相關係數分別為r =0.1859 與-0.1874 ，均為不顯著。由此可推知，耐寒與抗白葉枯病因子之分離係獨立，似無相互牽制連鎖現象。因此吾人欲育成抗病耐寒之秈稻品種，可以一般育種方法，將稉稻抗病耐寒因子轉移於秈稻品種。
Most of the indica rice varieties in Taiwan are found susceptible to bacterial leaf blight (Xanthomonas oryzae ) and sensitive to low temperature, especially during the nursery of first crop and ripening stage of second crop. The bacterial leaf blight disease seems to be associated with low temperature. It may become severe in indica rice. In order to clear genetic correlation between bacterial leaf blight disease and cold tolerance, experiment was carried out by using introduced rice variety PI 162319 (resistance to B. L. B. and low temperature) to cross with the local varieties Chianung Sen 11 and Chianung Sen yu 12 (Susceptible to disease and sensitive to low temperature). Two F2 populations and their F3 progenies were subjected to genetic analyses. Results obtained from this experiment were as follows : It was found that the differences of the bacterial leaf blight reaction of the two F2 populations between cold treatment and control were not significant at 5% of probability. This means that the two characters segregated independently.
There were no significant correlations between bacterial leaf blight resistance and cold tolerance ( r=1,859 and _0,1874 for respective cross) in their F3 progenies.
It is recommended to use the japonica rice for varietal improvement of indica rice. Most indica rice varieties are susceptible to cold temperature which can be improved by transfering the cold tolerant gene from the japonica rice
(24(1-2):1-10)YIELD AND RESISTANCE OF RICE BLAST RESISTANT COMPOSITE VARIETIES
No full text1. 抗病品系之混合品種較感病品種確有控制稻熱病蔓延之效。臺南5號或嘉南8號均為感病品種，其第一期作葉稻熱病之罹病率分別為35.7％及85.3%。第二期作為50.2％及89.2％。混合品種之罹病率，第一期作以5-1、9-1及31-2最低，僅有1.0％之罹病率，最高者為40-2，但亦僅有5.1％。第二期作以3-1及5-1之罹病率最低(罹病率1.5%)，以7-1最高(罹病率10.5%)。至於穗稻熱病之罹病率亦很明顯的可以看出混合品種低於對照品種。
2. 在發病地區混合品種與對照品種的稻穀產量，一、二期作均顯示品種間有極顯著的差異存在。第一期以33-2產量最高，次為41-2、40-2、31-2、3-1等品種。第二期作因發病程度較第一期為嚴重，混合品種單位面積產量有更突出的表現，如41-2產量較對照品種約增收一倍以上，其他各混合品種亦增收40~70％之間。由此可認定在稻熱病發生地區種植混合品種有穩定產量之功效。
3. 一般環境下，種植混合品種之結果，顯示在臺北及嘉義品種間產量差異不顯著。屏東第一期作以嘉南8號產量最高，41-2次之，但差異並不顯著。第二期作品種間差異極顯著，以3-1及7-1產量最高，分別較對照品種增產30％及10%，其他品種問差異不顯著。
This study is aimed at developing composite varieties which are composed of promissing blast resistance lines from Taichung 184, 186, Taichung yu 115, Pino 4 and C 115, with the genetic background of varieties Tainan 5 and Chianan 8. The blast resistance of composite varieties was tested at Pinglin where the disease prevails severely in both the 1st and 2nd crops. For the yield trial, four locations were included, namely Pinglin, Taipei, Chiayi and Pingtung. Results of the study are concluded as follows:
1. The composite varieties gave a successful control over the prevalence of the disease. The degree of leaf blast infections of the recurrent parents Tainan 5 and Chianan 8, was 35.7% and 50.2% in the 1st crop, 85.3 and 89.2% in the 2nd crop, respectively, while that of the composite varieties ranged from 1.0% (varieties 5-1, 9-1 and 31-2) to 5.1% (variety 40-2) in the 1st crop, and 1.5% (varieties 3-1 and 5-1) to 10.5% (variety 7-1) in the 2nd crop, with an average of 3.27%.
2. The composites outyielded the recurrent parents by 10-34% in the 1st crop and
57-104% in the 2nd crop. The difference was highly significant, especially, when the disease epidemic was severe in the 2nd crop.
3. With the non-infected plots in Taipei and Chiayi, no significant difference in grain yield was observed between the composites and the parental varieties. However it was significant at Pingtung district in both rice crop seasons. The composite varieties 3-1 and 7-1 outyielded Tainan 5 by 10-30%, while varieties 40-2, 31-2, 33-2 and 41-2 yielded less than Chianan 8 by 5-13% in 2nd crop season
(23(1):1-8)STUDIES ON THE HYBRID VIGOR OF RICE (III) THE RESPONSES IN GRAIN YIELD AND YIELD COMPONENTS OF F2 POPULATIONS AND VARIETIES UNDER FOUR DIFFERENT GROWING CONDITIONS
No full text本試驗主要目的，在探討F2羣體在不同栽培條件下對稻谷產量及產量構成要素的影響。供試材料有臺中65號，F2（臺中65號×臺南3號），臺南3號；光復401號，F2（光復401×臺農38號），臺農38號及臺農61號，臺北309號等8組合。行株距兩處理，即25cm×20cm及25cm×10cm；肥料兩處理，即N-P2O5-K2O分別為80-60-60及120-60-60(kg/ha)。試驗結果以對照品種臺農61號的產量最高，臺北309號居次，臺中65號的產量最差。兩F2羣體的平均產量比其四親本的平均數為高。F2羣體在四種不同栽培環境下的反應，一般而言，均與其親本或對照品種相一致。在第一期作密植對產量無顯著的效果，雖然單位面積穗數因密植而增加，但一穗粒數則相對的減少。增肥在普植區可以增加一穗粒數，卻使千粒重及結實率下降，結果產量低減。增肥密植的結果，一穗粒數並無顯著的增加，千粒重及結實率卻顯著的下降，而使產量低落。第二期作除密植顯著的增加單位面積穗數之外，不同栽培環境對水稻的產量及產量構成要素無明顯的效果，但F2羣體在不同栽培環境下的變異範圍似較其他品種為小。水稻本身似具有相當的調節力量，以適應不同的栽培環境。
The objective of this experiment is to compare the responses in grain yield and yield compoents of F2 populations to that of their parents as well as commercial rice varieties under four different growing conditions. Two F2 populations, Taichung 65 x Tainan 3 and Kwanfu 401 × Tainung 38 ; four parents, Taichung 65, Tainan 3, Kwanfu 401, and Tainung 38 ; and two commercial varieties, Tainung 61 and Taipei 309 were used as experimental materials. Two spacings, 25cm × 20cm and 25cm × 10cm, and two nitrogen levels, 80 and 120 kg/ha of pure nitrogen were combined into four different growing conditions, and all F2 populations and varieties were planted under the four treatments. The field layout was a split-split plot design with four replications.
In general, the respones in grain yield and yield components of the two F2 populations under four different growing conditions revealed the same tendency as their parents and the two commerial varieties. In first crop of 1971, close spacing increased the panicles per unit area, but decreased the grain number per panicle, showed little response in grain yield. The high rate of nitrogen application positively responsed in grain number per panicle, but negatively responsed in 1,000 kernel weight, percentage of fertility, and grain yield. The close spacing with high rate of nitrogen application could only decline the 1,000 kernel weight, percentage of fertility and grain yield.
In second crop of 1971, all the materials planted under different spacings and nitrogen applications did not show any clear trend in grain yield and yield components except the close spacing did increase panicles per unit area. The responses in grain yield and yield components of F2 populations, however, showed a little bit narrower range of variation than the rice varieties under the four growing conditions. The data of this experiment also indicated that rice plant has the ability of compensation through its yield components under different growing conditions
(20(4):1-7)EFFECTS OF SELECTION IN TWO HYBRID POPULATIONS OF RICE PROPAGATED IN DIFFERENT CROP SEASONS II. SELECTION IN LATE SEGREGATING GENERATIONS
No full text本試驗以農林48號 × 臺中在來一號及嘉農242號 × Rizzotto二組合，雜交後代以混合法處理，至F6代始按期作分別選拔，為探討後期世代實行分期育種之選拔效果，能否受氣候環境之影響。F6世代始按選拔方式分為三種處理，即一期作選育，二期作選育及一、二期連續選育。F6世代選單株，當選之F6單株在F7成為系統，並各選出21系統，聯合各處理當選品系及一對照品種，在一期作及二期作環境試驗，所獲結果摘要如下：
在二期作環境，嘉農242號 × Rizzotto組合，以二期作選育品系之平均產量最高，但與一、二期作連續選育兄系相比較無顯著差異；一期作選育品系則顯著地比其他二者為差。農林48號 × 臺中在來1號組合，以一、二期連續選育品某之平均產量最高，而二期作選育品系比其他兩者為差。一期作環境之試驗與二期作之結果相類似，但在嘉農242號 × Rizzotto組合，一、二期連續選育品系之平均產量比二期作選育者為高。本試驗結果表示，一、二期連續選拔育種法所育成之品系，較分期育種法所育成之品系，無論在一期作或二期作，均有較穩定的產量。
As reported previously (6), the difference in selection efficiency in different crop seasons on several agronomic traits like grain yield, number of tillers per plant, etc., in early segregating eenerations were not always significant. In this study the effect of selection in different crop seasons initiated from late segregating generations of the same hybrids will be reported. Two hybrids, Nohrin 48 × Taichung (Native) 1 and Chianung 242 × Rizzotto, were separately grown in both the first and the second crop seasnos consecutively under the bulk method up to F5 generation. Then, three seed samples were taken from the harvested seed lot of each F5 population to provided the seed for growing the F6 and F7 in three different groups, the first crop season alone, the second crop season alone and both crop seasons. Eight thousand plants consisted a population in the F6 and 80 plants were selected from them to establish plant-row in the successive F7. Finally, 21 lines were selected from each of the 3 populations to establish strains for yield trail.
In the second crop of 1968, the difference among average yields of three strain-groups derived from the F1 of Chianung 242 × Rizzotto was highly significant. The strains selected in the second crop yielded the highest in average among these three train groups, though their average yield did not significantly differed from that of the strains seleted in both crop seasons. Among the three strain groups derived from the F1 of another cross, Nohrin 48 × Taichung (Native) 1, the strain group selected in both crop seasons yielded higher in average than the rest of two strain groups, though signigicantly outyielded only the strain group selected in the second crop season. The result of the 1969 first crop was similar with that obtained in the 1968 second crop, except in those strains derived from the F1 of Chianung 242 × Rizzotto, among which the strain group selected in both crop seasons significantly outyielded the strain group selected in the second crop season. The results of this experiment seem to indicate there is little advantage in growing F6 and F7 hybrid materials in a particular season for efficient selection
(31(4):255-264)Cold Tolerance of Rice at Seedling Stage - I. The Reaction of Rice Varieties at Different Seedling Stages
No full text本試驗之目的是以植物生長箱檢驗不同苗齡對低溫之反應，並查不同類型水稻品種的耐寒性，以探尋可靠的檢定方法及了解各品種之耐寒性，俾供抗寒育種或有關試驗之參考。使用光照強度為270 Microeinsteins m-2Sec-1，而光照時問12 小時／天，以10℃之低溫處理秧苗9 天，並以秧苗存活率表示其耐寒性。試驗結果摘述如下：
將7 個稉稻品種，13 個秈稻品種共20 品種，每隔3 天播種一次，連續播10次，在低溫處理前，調查參試之20 品種各播種期的苗齡供參考，試驗結果稉稻較秈稻耐寒。參試品種中稉稻以USSR No.45，藤坂5 號，新竹糯4 號較耐寒、秈稻是以臺農秈育2414 及上杭大冬較耐寒。一般說4.5 葉齡的秧苗對低溫最敏感，而在3.5~4 葉齡時耐寒性品種間之差異最大。
以IR 29 與臺農67 號之正反交及其與臺農67 號同交之4 個F2集團在3.5 葉齡時，進行耐寒性檢定。結果，臺農67 號為耐寒品種，而IR29 對低溫極敏感，且臺農67 號之耐寒性主要受一對顯性遺傳因子控制。
以162 個水稻新品系在3~3.5 葉齡時，進行耐寒性檢定。結果只有10 個品系之存活率高於80%，而存活率在61~80%的亦只有3 品系，顯示新品系對低溫敏感，應於育種時引進耐寒基。
The main purpose of this experiment was to research the basic data for screening cold tolerant vaieties and breeding matherials of rice. A plant growth chamber was used to control the air temperature, which was set at 10°C for 9 days. The light intensity was 270 Microeinsteins m-2Sec-1for 12 hours per day. The experimental results were summarized as follows:
Seven Japonica and thirteen Indica rice varieties were used for this experiment. All twenty varieties were planted ten times at 3 day intervals. The leaf age of each rice variety at each planting was recorded just before low temperature treatment. (see Table I) The results showed that Japonica rice varieties were more tolerant to low temperature than Indica rice varieties. Among the cold tolerant varieties, Fujisaka 5 and Hsinchu Waxy No. 4 are Japonica rice varieties, while Tainung Sen Yuh 2414 and Shang Hung-Ta-Dong are Indica. Based on the survival rate of seedlings, the most sensitive stage was at 4.5 leaf age, while the biggest varietial differences was at 3.5-4 leaf age.
According to the basic information mentioned above, four F2 cross-combinations were used for screening the cold tolerant plants at 3.5 leaf age. The rate of survival plants of each F2 Population was recorded in Table 3. It showed that IR29 was a cold susceptible rice variety, and Tainung 67 was a cold tolerant variety. Based on the four F2 populations, cold tolerance of Tainung 67 was found to be governed by one pair of dominant genes.
In addition, 162 rice strains were used for cold tolerant testing at 3-3.5 leaf age. Only 10 strain had a seedling survival rate higher then 80%. The results indicated that most of the breeding materials tested were cold susceptible. Therefore, we may conclude the cold tolerant genes should be transfered into the breeding program, especially for indica rice
(22(1):1-6)MODIFIED TECHNIQUES OF RICE HYBRIDIZATION
No full text水稻雜交技術為改良水稻品種重要技術之一，早在1901年日本Hoshino即已使用剪穎法進行水稻的人工雜交。剪穎法的主要缺默是剪去內、外穎之一部份，使米粒的一部份暴露於外，於播種時容易引起病害，而使雜交種子的成活率降低。為了避免使內外穎剪傷，印度Sharngapani(1924）改用人為鑷開兩穎法，即在水稻自然開花之前約兩小時，用手輕輕的將內外穎拉開，用鑷子除去雄蕊，兩小時後普通稻花開放時，將已去雄的小花授粉，然後將內外穎合上，並用細絲線將該小花綑起來即行。這種方法手續太繁，雜交成功率亦因內外穎拉開時受傷而低減，故應用者少。另外Ramiah(1929）發現以人為的方法增加溫度，可以促進水稻開花。他以黑色紙袋套在母本的穗上，藉黑色吸收陽光的熱能促進開花，而在花粉未成熟之前完成去雄工作。此法在溫度太高或太低的情況下效果可能不理想。1933年Stephens等以溫湯去雄法（Hot water method）處理高梁成功後，Jodon於1936年開始研究溫湯去雄法應用於水稻的可能性。1938年氏終於成功的發表了他的溫湯去雄法。他發現水溫在44℃以上將使稻花組織受到傷害，在40℃到44℃之間處理10分鐘將殺死花粉而不傷害到其他器官。這種方法可使水稻行大量去雄工作。1940年臺灣農業試驗所的加茂氏另創暗室去雄法，即在稻花正常開放前2小時，將選定的母本移入暗室，等其開花鋒用鑷子將雄蕊除去而完成去雄工作。此法因受天氣影響頗大，不太容易控制，如移入的時間過早，沒有促進開花的作用；如移入太遲，則開花時粉囊已裂開，易發生自花授精。渡邊忠夫（1951）乃綜合Jodon與加茂的方法而創溫湯暗室並用法，即母本應用Jodon的溫湯去雄法去雄，父本應用暗室法促進其開花，並首先採用集體授粉法，此法的雜交成功率為46%～100%。
為了特殊研究目的，想獲得大量的雜交第一代種子，則上述方法有待更進一步的改進。國際稻米研究所於1963年以改良式剪穎法從事大量雜交工作，即於雜交前一天下午先行剪穎，緊接著再剪去雄蕊；或於雜交當天上午正常開花前剪去雄蕊，於正常花開放時將父穗的花粉振落於母穗上（或稱集體授粉）。結果雜交結實率為27.31％~49.77%，平均為38.63%。此法把去雄與授粉分兩天進行，因此可以雜交較多的小花；但小花是否將於第二天開放？雜交當天去雄如太遲將有自花授粉之慮，其自花授精為5%。因此該所於1964年將去雄工作限於雜交前一天完成，即剪穎後用鑷子除去雄蕊，結果其雜交結實率為43%，而自花授精率降為0.4%。
農試所為了研究水稻雜種優勢及回交育種，每年均需雜交大量的小花。雜交大致採用渡邊忠夫的方法，但母本經溫湯處理後僅能保持約1小時的開放狀態，之後內外穎就閉合。換言之，花粉必須在此時間內成熟，否則無法進行授粉工作。為解決此問題，先後就延遲內外穎的閉合，促進父穗開花，促進父穗花粉成熟，以及如何保存父穗的花粉等問題進行探討。其中以延遲內外穎閉合最為困難，因而以剪穎法配台之。本報告即以此方法所得結果與一般方法比較，供稻作同好者參考。
The various techniques of artificial hybridization in rice have been reviewed. Each, however, is unsatisfactory for the large numbers of hybridizations required for back-cross breeding and certain special studies. A modified Watanabe’s method has been developed. The florets are emasculated by hot water method in the morning, and will be clipped off of upper part of the glumes, if the florets closed before pollination, in order to allow the pollen to go into the glumes by shaking panicles of the pollen parent over the clipped florets (Mass pollination). The results showed that the modified method increased the percentage of seed set from 43% to 75%, in comparison with the modified clipping method developed by The International Rice Research Institute. The Watanabe’s method gave a wide range of percentages of seed set in the experiments. The percentage of seed set is high, if pollination can be done before the florets closing. On the contrary, if the anthers of the pollen plant mature after the florets closing, the percentage of seed set will be very low, sometimes, no grain can be obtained. The modified method, however, maintained higher and stable percentage of seed set by comparison, especially under the poor weather condition
(25(3):191-198)BREEDING AND GENETIC STUDIES OF BACTERIAL LEAF BLIGHT RESISTANT VARIETIES OF INDICA TYPE OF RICE－I. Resistance to bacterial leaf blight and yield trials of new-bred strians
No full text為探討75個新育成秈稻品系對白葉枯病之抵抗性及其利用價值，於1973分別在臺北、臺中、嘉義及屏東等四個地區進行抗病與米質檢定，及產量等調查工作，以供各場所從事秈稻育種之參考。
1. 供試品系中抗白葉枯病者，計有南秈育24號、高秈育55號、高秈育58號、高秈育54號、嘉農秈育l號、IR580-30-2、系比592120及系比592121等8品系，其中南秈育24號除具有抗病性狀之外，其稻穀產量及米質亦均有優異表現。
2. 供試品系中，第一期作之稻穀產量遠較第二期作為高，平均相差達35％之多。(如圖2)
3. 米質特優者計有南秈育24號等16品系。
4. 植株高度除高秈育68號等3品系較高外，其餘均在100公分以下，而以85公分左右者居多；第二期作又較一期作為高。(如圖3)
5. 生育日數除新竹矮腳尖等4品種（系）較早熟外，大部份較臺中在來1號及高秈2號等品種晚熟。(如圖1)
75 strains of newly－developed indica rices from various stations were screened for high yield as well as resistance to bacterial leaf blight disease. The artificial inoculation were made by clipping method at the later gowth stage of rice. The tests were conducted at Taiwan Agricultural Research Institute and Taichung, Tainan (at Chiayi) and Kaohsiung District Agricultural Improvement Stations in 1973.
The results obtained are summarized as follows:
1. Eight strains of indica rice, i. e. Nan-sen-yu 24, Kaohsiung-sen-yu 54, 55,58. Chianung-sen-yu 1, JR 580-30-2, Sipi 592120 and 592121 showed resistance to the 604 strain at both the first and second crops. Three of the eight resistant strains were good in grain quality, especialy Nan-sen-yu 24 which showed the highest yield as well as the best quality among all the entries tested. It could be used as a valuable breeding material for improving local varieties.
2. The yield of newly-developed indica rices was 35% lower in the second crop than in the first crop. (Table 2)
3. Among the 75 entries tested, Nan-sen-yu 24 and other 15 strains showed excellent grain quality.
4. Plant heights varied from 73 to 113 cm., hut most strains were 85 cm. in height. In general, rice plants of the second crop was higher than that of the first crop. (Table 3)
5. Except for Ai-Chueh-Chien, JR 580-30-2 and Kaohsiung-sen-yu 55 etc. which showed a growth duration shorter than the check varieties (TN 1 and Kaohsiung sen 2), all other tested entries were longer
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