• 作者： 鄔宏潘; 羅其正
• 作者服務機構： 中央研究院植物研究所
• 中文摘要： 稻米為我國之主要糧食，每年生產量約250萬公噸，最近由於耕地日減，提高單位面積生產力甚為重要。本研究分為三部份探討單位面積生產力提高之可能性：(1)氣象因素之變化與生產力之關係—探討最近十年來水稻生育期內氣溫與雨量的變化對產量的影響。(2)水稻新種源之尋找—自IRRI引進76品種，探討其適應能力，以增加新種源。(3）栽培環境改善之檢討—藉生育期中之栽培環境之調整，以改變生育及株型，探討生產力提高之可能性。結果如下： 1. 氣象因素之變化與生產力之關係：按期作別，每期可分為四型，北部地區一期幼穗分化後之高溫可提高生產力，但多雨使生產力降低；二期作幼穗分化到抽穗期之高溫多雨使生產力降低，但抽穗後之高溫可提高生產力。中部地區一期作移植時之多雨及抽穗後之高溫對生產有利；二期作移植時及幼穗分化時之高溫以及抽穗時之多雨對產量無益。南部地區一期作時幼穗分化之高溫對生產無益，但移植到分蘗盛期時之多雨以及抽穗後之高溫可提高生產力；二期作移植時高溫影響生產力。東部地區一期作抽穗後之高溫對生產有利；二期作分蘗時及抽穗後之高溫對生產有利，但幼穗分化時高溫多雨影響生產力之提高。改變移植期以減少氣溫及雨量之限制，在目前之品種特性下似不太可能。 2. 水稻新種源之尋找：76品種中能順利結實者有61品種，而二期作產量較高者有41品種，其中有19品種之單位面積產量超過4噸∕公頃（南港），因穗數及稔實率較一期作為優之故。但這些種源大都罹穗頸稻熱病、紋枯病或小粒菌核病（嘉義），尚須改善其抗病性後才能供於實際栽培之用。 3. 栽培環境改善之探討：生育控制下一期作可增加產量15～39％，二期作除臺南5號外，臺中65號及新竹矮腳尖各提高17％及20％，其效果大都由於密植之故。營養生長期之銨態氮追肥可增加穗數及顆花數，而硝酸態氮則可增加稔實率及千粒重。生殖生長期之兩種追肥對稔實率及千粒重無多大效果，因其根系之吸收能力降低，二期作後期日照量又不足，對產量無促進之效。
• 英文摘要： Rice in Taiwan has been the principal foodcrop, but its average yield is less than thatin several countries. Increasing the per unitarea productivity is presently important as thedemand for land increases. For this purpose,this study has been programmed in three parts.To find out the correlation between climaticfactors and rice productivity, changes of tem-perature and rainfall during the rice growingseasons in the past decade were studied. Tosearch for promising new rice gene sources, 76varieties were imported from IRRI and theiradaptabilities were tested. To enhance produc-tivity, the effect of various cultivation methodswas examined. The correlation of rice yield with climatevaries with locality. In the north, in the firstcrop, high temperature after panicle initiationhas a positive effect on the yield whereas rainyweather has a negative effect. For the secondcrop, high temperature and rainfall in the head-ing stage can be harmful to yield；however,warm temperature after heading promote yield.In the central region, the first crop is favoredby rain during transplanting time and warmtemperatures after heading, while in the secondcrop the productivity goes down if it is warmduring the transplanting and the panicle ini-tiations stages or if it is rainy in the headingperiod. In the south, hot weather duringpanicle initiation of the first crop as well asthe transplanting of the second crop interferesthe yield. The yield of the first crop is greaterif there is rainfall in the period from transplant-ing to the maximal tillering stage, and hot wea-ther after the heading. In the east, the favor-able factors are warm temperatures after theheading of the first crop and during tilleringand heading of the second crop. The yield ofthe second crop is reduced when it is warm andrainy during the panicle initiation. It is pro-bably not possible to avoid the influence of theclimate factors for the rice varieties now beingcultivated by shifting the transplanting schedule. Out of the newly imported 76 IRRI ricevarieties, 61 succeeded in producing grains. 41were regarded as high-yielding for the secondcrop, and of these 19 had unit area productivitythat exceeded 4 tons per hectare in Nankang.The panicle number and the ripening rate ofthese varieties are better in the second cropthan in the first. The ruin disadvantage ofthese IRRI varieties is that they are quite sus-ceptible to such diseases as rice neck blast,sclerotial rot and sheath blight. Therefore, re-sistant lines must be developed before they canextensively by grown. The intensive planting method is effectivein increasing the first crop yield by 15-39％.For the second crop, this method also improvedthe productivity of Taichung 65 and HsinchuAi-Chuaw-Chien by 17 and 20％ respectively,but not yield of Tainan 5. Application of (方程式無法摘錄) fertilizer to rice during the vegetativegrowth increases the number of panicles andspikelets while (方程式無法摘錄) enhances the ripeningrate arid the grain weight. Neither applicationin the reproductive stage has any effect, be-cause the root system is too poor to take upnutrients and solar energy is insufficient at thattime. These results hold for both first and se.cond crop.
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