Comparison on the Yield and the Production and Distribution of Dry Matter in Rice between Crop Seasons

本試驗於1981年二期作與1982年一期作分別在屏東與臺中二地區進行，在水稻生育期間測定不同器官內乾物質、全氮及非構造性碳水化含物（TNC）含量的變化，以明瞭品種間、區域間與期作間產量差異的原因。 水稻抽穗時之全株乾物重以一期作為高，其中以屏東區臺農67號差異最為明顯，臺中地區臺農67號及臺南5號的差異較小。二期作稻抽穗期全株乾物重低落原因主要受分蘖數較少的影響，就單一分蘗平均乾重進行比較，反以二期作稍高。抽穗後穀粒發育期間乾物質的生產量，亦以一期作顯著優於二期作，屏東地區的差別最為明顯。 一期作水稻抽穗時莖稈內江NC濃度顯著高於二期作，抽穗期營養器官內TNC含量為二期作之1.5-5.5倍，表示有較多的預貯物質。抽穗後穀粒充實期間，屏東、臺中二地區之一期作TNC生產量高於二期作。非構造性碳水化合物收穫指數(HTNCI)均高，介於0.93-0.98之間，無地區、品種或期作性差異。而產量經由預貯物質而來的百分比（Pre-heading storage contribution)，一期作介於17.8-22.5%之間，二期作為11.6-17.9%。 葉片為水稻植株內含氮濃度較高之器官，屏東、臺中二地區於抽穗期葉片氮濃度表現不一致，但屏東區臺農67號葉片內氮濃度明顯的以一期作為低，和一期作極高產與二期作低產的表現，可推知抽穗期葉片內全氮濃度的高低與產量問的關係並不單純，植株的全氮收穫指數(HNI)以一期作為高，介於0.70-0.81之間，二期作為0.65-0.76，顯示前者有較多的轉流量，氮代謝作用與碳代謝作用之間可能互為影響，值得進一步研究。 期作間產量差異比較發現，千粒重差別不大，每穗穎花數與結實率乘積在期作間亦相似，穗數為決定產量的最主要因子。二期作低產除了穗數較少及抽穗時乾物重與TNC含量較低外，穀粒充實期間乾物質淨生產量亦較低，為今後謀求二期作水稻增產應注意的方向。 Two rice cultivars, Tainung 67 and Tainan 5, were grown in either Pingtung or Taichung area in the second crop of 1981 and first crop of 1982. Dry weight and contents of total nonstructural carbohydrates (TNC) and total nitrogen (N) in different plant fractions were detennined at stages of grain-filling. The purpose of this study was to investigate the causes of yield difference due to location, varietal or seasonal factors. Dry weight per hill at heading was consistently higher for the first than for the second crop. The difference was most significant for rice grown in Pingtung area. The lower dry weight of the second crop rice was due mainly to the fewer number of tillers per hill. Results showed that on a per tiller basis, the second crop rice possessed higher dry weight. The capability of dry matter production was higher for rice of the first crop season. Culms of the first crop rice contained 1.5-5.5 times more TNC than those of the second crop rice at heading, a result of higher TNC concentration and dry weight per hill. The production of TNC during grain-filling was supperior for the first crop rice. Regardless of crop season or location, the harvest TNC index (HTNCI) ranged between 0.93 to 0.98. In other words, the efficiency of utilizing TNC by the rice was extremely high. The contribution of preheading storage to yield were 17.8-22.5% and 11.6-17.9% for the first and second crops, respectively. No consistent relationship between N concentration in leaf blade at heading and final grain yield was observed. However, compared to the second crop, the first crop rice in Pingtung had lower leaf blade N but significantly higher yield, indicating the correlation between these two characters was not simple. Harvest N index (HNI) was 0.70-0.81 for the first and 0.65-0.76 for the second crop. The interaction between the translocation of N and TNC from vegetative tissue to the grain was suggested. Analysis of yield componts showed similar 1,000-grain weight and product of spikelet number per panicle by the percentage of ripened grain. The lower yield of the second crop rice was caused by few panicle number and lower contents of dry matter and TNC at heading. The enhancement of photosynthetic capability during grain-filling was also of utmost importance in terms of increasing the yield of second rice crops in Taiwan

(36(1):29-40)Accumu1ation and Distribution of Nutrients Soybeans－III. Accumulation of TNC, N, P, K and Mg during Plant Development

以高雄3 號（Kaohsiung No.3 ）與十石（Shih-Shih ）二大豆品種為材料，於重要生育期測定植株各部位所累積之非構造性碳水化合物（TNC ）及氮、磷、鉀與鎂素含量，並於春、夏作間進行比較，以探討營養要素與產量間之關係。在R4-R5 生育期以前，葉片為營養要素累積量最高的器官，且春作大豆全株與各營養器官內的要素含量多較夏作為高，其後之營養要素累積以莢果壁與種子為主，且以夏作的含量較多。全生育期大豆植株累積各要素之最高量為每公頃氮素124-270kg 、磷素27-42kg 、鉀素70-130kg 與鎂素15-30kg ，其中僅磷素與所施用之肥料量相平衡。種子迅速充實期全株各元素之累積速率（kg / ha / day ）為氮素3-8 、磷素0.3-1.2 、鉀素1.4-3.8 與鎂素0.3-0.8 ，而種子之累積速率則依次為4.4-12.9 、0.7-1.7 、1.8-2.6 與0.3-0.5 ，顯示除鉀與鎂外，其他營養要素明顯自葉片、葉柄、莖桿及莢果壁等器官再轉移至種子。種子充實期間莢果壁TNC / N 比值上升，夏作遠高於春作，種子TNC / N 比值則有逐漸下降的趨勢，且以春作略低，顯示夏作大豆TNC 生產力較高，春作則有不足的可能，應為影響產量的重要原因。 Soybean varieties Kaohsiung No. 3 (KS 3) and Shih-Shih (SS) were grown in the summer (1981) and spring (1982) crop seasons to study the amounts of TNC, N, P, K and Mg accumulated by different plant organs during successive developmental stages. Between V3 and R5 stages, leaf blade was the organ of predominant nutrient accumulation and the amounts accumulated by the whole plant and various vegetative organs were greater for the spring than for the summer crop. Pod wall and seed were the major organs of nutrient deposition during seed-filling. The amounts of TNC and mineral nutrients accumulated in the reproductive organs as well as in the whole plant were higher for the summer crop during the same period. The maximum amounts of nutrients accumulated by soybean crop were 120-270 kg N/ha, 27-44 kg P/ha, 70-130 kg K/ha and 15-30 kg Mg/ha. The accumulation rates (kg/ha/day) by the whole plant during rapid seed-filling were N: 3-8, P: 0.3-1.2, K: 1.4-3.8 and Mg: 0.3-0.8; whereas the rates by the seed were N: 4.4-12.9, P: 0.7-1.7, K: 1.8-2.6 and Mg: 0.3-0.5. These results indicated significant retranslocation of N and P from vegetative organs to the developing seeds. TNC/N ratio in the pod wall increased markedly during seed-filling and was significantly higher for the summer than for the spring crop. On the contrary, TNC/N ratio in the seed showed a decreasing tendency during the same period. It was also slightly higher for the summer crop. Poor ability of TNC production was suggested as one of the factors for the low grain yield of soybeans grown in the spring crop season

(33(4):363-371)Comparison on Some Agronomic and Physiological Characteristics between Rice Varieties Differing in Grain Weight

試驗採用大粒型水稻品種（千粒重約45g）Arborio 與中粒型品種臺農67 號（千粒重約25g）為材料，於民國72年第一、二期作在田間栽培，在水稻生育期間定期調查株高與分蘗數測定葉面積指數（LAI ）與乾物質累積之變化，並分析葉片內全氮與可溶性蛋白質之濃度，以比較不同粒重水稻。品種的農藝與生理特性，探討利用大粒品種之可行性。Arborio 幼苗具有極強的生長優勢，尤其在第一期作低溫與低日照環境下的生長極為快速，顯著優於臺農67 號，但其開始分蘗的時間較晚（移植後37 日），在一期作的分蘗期間僅有三週左右，故分蘗數較少，又由於有效分蘗百分比低，故穗數亦少於臺農67 號（分別為14 、21），可能為限制產量的主要因子。大粒型品種生育初期的株高增長較快，但成熟期之株高117cm 與臺農67 號113cm 差異不大。抽穗以前LAI 之變化受分蘗數之影響很大，亦以臺農67 號為高，Arborio 品種的LAI 多在4 以下，對乾物質生產有不利的作用。兩品種葉片內所含葉綠素濃度相近，但在抽穗以後，Arborio 之全氮與可溶性蛋白質濃度均較臺農67 號為高，唯向一時期穗重及全株乾重之增加反不如臺農67 號，且對抽穗前預貯物質之依賴較高。試驗結果建議分蘗數少與後期光合能力低落為大粒型品種Arborio 主要缺點，今後除應選取短稈與分蘗性強之大粒種源做為育種材料，對各項生理與栽培特性亦有詳加探討的必要。 One large-grain rice variety, Arborio (1,000-grain-weight of 45g), and one medium- grain variety, Tainung No. 67 (1,000-grain-weight of 25g), were used in this experiment. Some agronomic and physiological characteristics were determined during the growth course of the rice plants in both the first and second crop seasons. Seedling vigor of Arborio was significantly stronger than that of Tainung No. 67, especially under the conditions of low temperature and low solar radiation during the first crop of 1983. The initiation of tillering was late and the effective tillering duration was short for Arborio and hence the large-grain variety had fewer tiller number when compared with Tainung No. 67. Panicle number was also fewer for Arborio as a consequence of lower percentage of effective tiller. Leaf area index (LAI) before heading was strongly affected by tiller number. LAI of Arborio was generally below 4.0 and unfavorable effect on dry matter production was thus suggested. The two varieties contained similar chlorophyll concentration whereas Arborio had higher concentrations of total nitrogen and soluble protein, particularly during grain-filling. However, the dry weight increase of both panicle and total plant was inferior during the same period and the dependence of yield to preheading storage was more apparent for Arborio. Experimental results indicated that poor tillering ability and lower photosynthetic production during grain-filling were the major hindrances in utilizing large-grain varieties for commercial culture. Short-stat- ured, large-grain germplasm with more tiller number was suggested as useful breeding material in improving the yield potential of rice crop

(39(3):165-173)Effect of Controlled Pollination on the Characteristics of Ear and. Kernel Development of Tainung 351 Maize

本試驗以單雜交玉米臺農351號為材料，以套袋方式延遲授粉，縮短果穗上、下位子粒發育之時間差距，又限制穎花有效受粉時間，探討對玉米果穗不同部位子粒生育性狀及產量的影響。套袋延遲授粉有減少上位果穗不充實部份長度、增加穗周與提高上位子粒數及產量的作用，但中、下位子粒之百粒重有因而降低的趨勢，延遲授粉7日並顯著減少中、下位子粒之粒數與產量。經由控制有效授粉期可使果穗不同部位的子粒數目發生變異，如以對照植株之粒數為準，自吐絲始期算起，上位穎花之受粉自第3日開始，9日內完成，與中、下位穎花分別於5及3日內完成受粉有顯著差異。果穗不同部位子粒之數目與平均百粒重間呈負相關，且上位子粒亦有充份發育的潛能。本試驗以控制授粉方式改變玉米果穗粒數及百粒重，發現不同部位子粒之間具有競爭作用，而縮短上、下位穎花受粉時間差距可增強上位子粒的相對競爭能力；經由確定穗內不同部位穎花有效受粉所需時間，認為自雌穗吐絲始期開始，最少應有5日的花粉供應方可維持較高之子粒產量，可供為品種選育及實際栽培時的參考。 Two experiments, grain competition and silking sequence, were conducted by using the single-cross maize hybrid Tainung 351 as experimental material. For grain competition study, pollination was delayed by bagging the ear at silking to reduce the sequential difference in kernel development between kernels positioned at different positions of the ear. For silking sequence study, maize ears were allowed to pollinate for only limited periods of time. The purpose was to study the effect of controlled pollination on the ear and kernel characteristics at maturity. Delay pollination tended to reduce the length ofJunfilled portion at ear-tip, and to increase periphery of upper ear, and both number and yield of kernels at the upper one-third of the ear. On the contrary, kernel number and 100-kernel-weight of the middle and basal kernels were reduced as bagging period was prolonged. Based on the kernel number of the control plant, silking sequence study revaled that pollination of upper spikelets commenced at 3 days after silking (DAS) and was completed at 9 DAS. For middle and basal spikelets, pollination was completed at 5 and 3 DAS, respectively. Negative correlation was recorded between kernel number and 100-kernel-weight. Through changing both kernel number and 100-kernel-weight by controlled pollination, it was assumed that competition existed among kernels at different positions of the ear. An effective pollination period of at least 5 days was also suggested for maintaining kernel yield of th is variety

(33(3):247-256)Accumulation and Distribution of Nutrients in Soybeans I. Changes of TNC and N Concentrations during Plant Development

本試驗以高雄3號（Kaohsiung No. 3 ）與十石（Shih-Shih ）二大豆品種為材料，測定重要生育期植株各部位（葉片、葉柄、莖桿、根、莢果壁與種子）非構造性碳水化合物（TNC ）與氮素濃度，探討春（1982 ）、夏（1981 ）作大豆由於此二重要營養要素濃度之變化所代表之生理意義及與產量之關係。試驗結果顯示春作大豆營養器官於種子迅速充實期前均有較高的TNC 濃度，而於種子迅速充實後大幅下降，成熟時各部位TNC 濃度反較夏作低，顯示春作大豆對營養器官所貯存TNC 的依賴程度較大，可能是因為春作大豆葉片較早老化、脫落而導致現階段光合生產不足，TNC 之供給成為產量的限制因子。 除葉柄外，春作各營養器官亦有較高N 濃度，尤以營養生長期之差異較大。與TNC 相同，各營養器官N 濃度在種子充實期有大幅下降及N 素再轉移現象存在。對老化即將脫落的葉片進行分析發現，夏作N 素濃度皆在2.5%以上，春作更高達3.5%，顯示葉片內大量的N 素無法充分轉移至種子，而此時TNC 濃度已低於5%，無助於維持葉片生理活性，因而首先提出假說，認為除TNC 外，可能尚有其他未知因子誘使葉片提早老化，並阻礙N 素之轉移而降低種子產量。同一期作二品種之TNC 及N 素濃度變化頗一為致，而期作間差異則大，顯示兩項營養要素之累積與分佈易受環境因子之影響。 Two soybean cultivars, Kaohsiung No. 3 (KS-3) and Shih-Shih (SS), were grown in the summer crop of 1981 and spring crop of 1982 at the experimental farm of Taiwan Agricultural Research Institute. Samples were taken at stages of soybean development. Concentrations of total nonstructural carbohydrates (TNC) and nitrogen (N) were determined on different plant parts including leaf blade, petiole, stem, root, pod wall and seed. TNC concentrations in the vegetative organs were very high and the decreases during seed-filling were also extremely prominent in the spring crop. In view of the lower TNC concentration in the senescing leaf blades and lower grain yield of the spring crop, insufficient supply of photosynthetic assimilates to the seeds was proposed as a result of early leaf senescence. Vegetative organs of soybeans grown in the summer crop had lower N concentrations than those grown in the spring crop. The decreases of N concentration in vegetative organs were apparent during seed-filling period, indicating the redistribution of N from vegetative organs to the seeds. Analysis of leaf blades sampled just before abscission showed N concentration of 2.5% in the summer and as high as 3.6% in the spring crop. The high N concentration in the senesced leaf blades indicated the uneffectiveness of retranslocating N to the developing seeds and the unavailability of N to the maintenance of physiological activities of the leaf blades. Changes of TNC and N concentrations in the two cultivars were similar within crop but were different between crop seasons, suggesting the influences of environmental factors were prominent

(33(1):12-23)水稻分蘗之生理研究 II.不同穗部容積品種的生產力比較

Amount of dry matter, total nitrogen and total nonstructural carbohydrates (TNC) in the leaf blades, leaf sheaths and stems from various node positions, as well as panicles, of rice tillers were analyzed at stages of grain development. The purpose of this study was to compare the potential of productivity between a large-grain variety Mira and a medium-grain variety Tainung No. 67. Nitrogen concentrations in various organs of Mira tillers were significantly higher, whereas TNC concentrations were lower, than those of Tainung No. 67 tillers. When compared to Mira on a per tiller basis, Tainung No. 67 produced 14-55% less dry matter and 36-39% less TNC during the test period. For a mature panicle from a single tiller, the amounts of dry matter and TNC accumulated by Tainung No. 67 were only 61-74% and 63-80%, respectively, of those accumulated by Mira. Those results indicated that the productivity per tiller was greater for the large-grain variety. As panicle number per hill was very low for Mira, community productivity was 50% higher for Tainung No. 67 in the first crop hut was comparable between varieties in the second crop. No difference in the increase rates of major components in panicles was found between varieties, indicating the absolute amount of translocation into panicles was greater for Mira. Results suggested that yield increase through enlarging grain size was possible. However, responses of the large-grain rice to the environmental factors should be further understood. 以大粒種水稻品種 Mira （千粒重約 379 ）及中粒型水稻品種臺農 67 號（千粒重約 25g ）為材料，自抽穗起每週以分蘗為單位取樣，測定源自不同節位之葉片、葉鞘、莖及穗部的乾物重，全氮及非構造性碳水化合物（ TNC ）含量的變化，目的在比較兩型水稻的生產能力。試驗結果發現 Mira 各器官內之全氮濃度顯著較臺農 67 號為高，每一分蘗吸收的氮量亦超出臺農 67 號 40 %以上。在穀粒充實過程的淨乾物質與 TNC 生成量比較，如以單一分蘗為單位，臺農 67 號分別較 Mira 少 14-55 %與 36-39 % ；成熟期時，臺農 67 號水稻之單一穗重僅為 Mira 之 61-74 % ，單一穗內 TNC 含量僅為 63-80 % ，顯示大粒型水稻單一分蘗的生產力較高，而推廣品種亦有再加改良的可能。由於大粒型水稻的穗數太少，故就群落生產力而言，一期作臺農 67 號較 Mira 高 50 %，二期作則兩品種相似，即 Mira 在第二期作有較優良的表現。兩品種穗部主要成份的累積速率相當，表示絕對轉流量以大粒型品種為高。本試驗結果建議，經由增大穀粒體積謀求稻作增產或有可能，但較大粒型水稻品種（系）對各項環境因子一諸如溫度，栽植密度、氮需要量等之反應，仍應先加以深入的瞭解