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(38(3):306-311)Changes in Heterosis of Maize Populations as Affected by Three Cycles of Combined Intrapopulation and Interpopulation Improvement
No full text在高產環境下，利用BS10及RSSSC兩個玉米族羣進行兼顧族羣內及族羣間改良之相互輪迴選拔。族羣內之改良包括多種葉病、莖腐病等抗病性之外表型混合選種及S1系統在高產環境下之產量評估。族羣間之改良則包括測交系統在高產環境下之產量試驗及選拔。三個循環之選種效應評估，分別利用族羣、族羣雜種及族羣測交種等，於四個不同環境下進行產量試驗。本試驗結果顯示：族羣本身、族羣雜種以及族羣測交種之子實產量之改良效果頗為顯著。子實產量之雜種優勢估值以族羣雜種（Fl）與二親本族羣平均（MP）差表之，在C0、C1、C2及C3分別為1.33、1.49、1.04及0.90噸／公頃。子實產量雜種優勢以100 ×（Fl－MP）/ MP表示，在C0為15.45％；在C1僅少許變化（15.69％）；在C2及C3則明顯降低為10.06及8.13％。此種雜種優勢弱化之現象或許受族羣中顯性基因頻度減少所影響。為避免雜種優勢之繼續弱化，選拔方式宜作適當調整。在S1系統及測交系統評估之同時，更加強調測交系統產量之重要性，對提高族羣雜種之選種效應與雜種優勢，應當有所助益。
A selection program using reciprocal recurrent selection procedures in maize (Zea mays L.) was developed. Intrapopulation and interpopulation selection procedures were used for two maize populations BS10 and RSSSC. Intrapopulation selection procedure included phenotypic mass selection for multiple leaf and multiple stalk-rot disease resistance and S1 family selection for grain yield in a high-yield environment. Interpopul-ation improvement involved selection of testcrosses of S1 family x inbred tester in a high-yield environment. Evaluation of populations per se, population crossses and populations x testers for response to three cycles of selection for grain yield were conducted at four environments. The results indicate that selection response was satisfactory in populations per Se, population crosses and populations x testers for grain yield. Heterosis estimates for grain yield calculated as differences between population crosses (F1) and midparents (MP) were 1.33, 1.49, 1.04 and 0.90 Mg ha-1 for C0, C1, C2 and C3, respectively. Heterosis calculated in 100×(F1-MP)/MP showed midparent heterosis in C0 was 15.45%. Subsequently, only a small change in C1 (15.69%), but a large reduction in C2 and C3, which were 10.05 and 8.13%, respectively. This reduction may indicate a decrease in the frequencies of dominant genes. Greater emphasis on testcrosses than on S1 families performance in this selection program is required to obtain better heterotic response
(37(4):366-378)玉米族羣相互輪迴選拔之選種效應評估
No full textA selection program using reciprocal recurrent selection procedures in maize (Zea mays L.) was developed. Intra-and interpopulation selection procedures were used for two maize populations BS10 and RSSSC. Intrapopulation selection procedures included phenotypic mass selection for multiple leaf and multiple stalk-rot disease resistance and S1 family selection for grain yield in a high-yield environment. Interpopulation improvement involved selection of testcrosses of S1 family×inbred tester in a high-yield environment. Evaluations of populations per se, population crosses and populations×testers for response to three cycles of selection for grain yield were conducted at four environments. Evaluation of populations per se and population crosses for response to three cycles of selection for multiple leaf disease and multiple stalk-rot resistance was conducted at disease nursery in 1985. The results indicate that selection response was consistent among environments. Gain from selection was satisfactory in populations per se, population crosses and populations×testers for grain yield, multiple leaf disease resistance and multiple stalk-rot resistance. Linear response to three cycles of selection for grain yield for BS10, RSSSC, BS10×RSSSC, BS10×B37, and RSSSC×B79 were: 0.95, 0.69, 0.65, 0.65 and 0.24 Mg/ha/cycle, respectively. The rates of gain for grain yield obtained in the present study compare favorably with published reports. Linear response for stalk lodging for BS10, BS10×RSSSC and BS10×B37 were: －9.0, －5.4 and －3.5%/cycle, respectively. All populations per se, population crosses and populations×testers showed significant increase in penetrometer reading. Increase in plant height and ear height were observed for RSSSC, BS10×RSSSC and RSSSC×B79. Population BS10 showed an increase in 300-kernel weight and kernel number per ear, and a decrease in ear number per 100 plants. Population RSSSC only showed an increase in 300-kernel weight. Three cycles of selection slightly increased grain moisture in BS10 and BS10×B37. This result indicates the procedures of selection in a high-yield environment are beneficial in improving grain yield, multiple disease resistance and stalk lodging resistance in maize populations per se and their hybrids.
在高產環境下，利用BS10及RSSSC兩個玉米族群進行兼顧族羣內及族羣間改良之相互輪迴選拔。族羣內之改良包括多種葉斑病、莖腐病等抗病性的外表型混合選種及S1系統在高產環境下之產量評估。族羣間之改良則包括測交系統在高產環境下之產量試驗及選拔。三個輪迴之選種效應評估，分別利用族羣、族羣雜種及族羣測交種等，於四個不同環境下進行產量試驗；並利用族羣及族羣雜種於病圃檢定其對葉斑病及莖腐病之抵抗性。試驗結果摘要如下：
（1）選拔效應不因評估環境之不同而有明顯差異。
（2）族羣本身、族羣雜種以及族羣測交種之子實產量、多種葉病與莖腐病之抵抗性等之改良效果頗為顯著。在子實產量方面，BS10, RSSSC, BS10×RSSSC, BS10×B37，及RSSSC×B79分別達到0.95、0.69、0.65、0.65及0.24噸／公頃／輪迴之增進效果。在抗倒伏性方面，BS10, BS10×RSSSC及BS10×B37分別為－9.0、－5.4及－3.5％／輪迴之選種效應。所有族羣、族羣雜種及族羣測交種之Penetrometer reading亦顯著地增強。
（3）就本研究之育種目標而言，相關性狀之改變，以合意者居多。其中較為不利之變化為RSSSC, BS10×RSSSC 及RSSSC×B79等之株高及穗位高之增加，及BS10每株穗數之減少。有利的部分則包括BS10之300粒重及每穗粒數，及RSSSC 300粒重之增加等。
（4）本試驗結果顯示：高產環境下進行相互輪迴選拔，對改良玉米子實產量、病害抵抗性及抗倒伏性成效頗著，為一有利的選拔方式
(42(1):12-18)Diallel Analysis of Mature Plant Resistance to Helminthosporium maydis in Maize
No full text六個玉米自交系親本及其十五個單交組合，於1991年秋作及1992年春作，利用田間自然感染，進行玉米開花後之成株對葉枯病（Helminthosporium maydis race 0）抗病性之遺傳分析。目交系發病等級在期作間相當一致，六個自交系中，Antigua-2D及Sw654對葉枯病具有極高的抗病性。組合力分析結果顯示，抗病性係由累加性及非累加性基因所共同控制，其中又以累加性佔極大之比例。本研究建議：利用譜系法或輪迴選種法，改良玉米成株葉枯病之抗病性，當可獲得較顯著之效果。
Six inbreds and their fifteen single cross hybrids were evaluated in fall of 1991 and spring of 1992 under natural epiphytotics for mature plant resistance to southern corn leaf blight (Helminthosporium maydis＝Bipolaris maydis) race 0. Inbred line Antigua-2D and Sw654 showed the highest level of resistance. Resistance of the inbred lines to H. maydis was consistent between crop seasons. Both general (GCA) and specific (SCA) combining ability were highly significant for resistance in fall and spring crop seasons. Additive effects were accounted for major part of the total variation. This result indicated that pedigree or recurrent selsction methods should be effective in breeding for improved resistance to southern corn leaf blight
(40(3):346-350)Methods of Measuring Seed Fillness in Peanut
No full text本省種植之大粒型落花生品種，籽粒常有不飽滿的現象，而籽粒飽滿度的測定，目前尚無一定標準。本研究採用臺灣省農業試驗所保存之落花生種源為試驗材料，四個類型各逢機選取20個品種，分別調查莢果及籽粒性狀，比較下列三種籽粒飽滿度測定方法：（1）乾籽粒體積／鮮莢果體積；（2）18／64吋篩網選獲之籽粒重／單株乾籽粒重；（3）種皮不皺縮乾籽粒重／單株乾籽粒重，以期選出最優之籽粒飽滿度評價方法。
試驗結果顯示：三種不同的測定方法反應不同的飽滿度值及測定意義，（1）、（2）、（3）法分別著重在籽粒充實度、籽粒大小及種皮不皺縮等特性上。其中，（1）及（3）法在Virginia Bunch型；（2）及（3）法在Spanish、Virginia Bunch及Runner型均有顯著之相關。就生理研究的觀點而言，（1）法較為可靠；然就消費市場評價標準，以及考慮育種選拔之操作方便，則以（3）法較為適當。Eighty peanut varieties were randomly sampled from 1,352 peanut germplasms, preserved at TARI, in the fall crop season of 1990. Pod and seed traits were investigated on single plant basis for comparison on the following measuring methods of seed fillness : (1)dry seed volumn/fresh pod volumn ; (2)weight of dry seed screened by 18/64 inch screen/dry seed weight ; (3)weight of nonshrivelling seed/dry seed weight.
Experimental results showed that different measuring methods provided different responses and meanings of seed fillness. Method (1), (2) and (3) emphasized on seed-filling capacity, seed size and nonshrivelling seed, respectively. There were significantly and positively correlated between method (1) and (3) in Virginia Bunch type; and method (2) and (3) in Spanish, Virginia Bunch and Runner type. Method (1) was considered as the most reliable measurement for crop physiological study, while methed (3) was the most convenient measurement for marketable evaluation and plant breeding
(41(3):233-240)Effects of Plant Density on Forage and Grain Yield of Maize with Different Kernel Types
No full text九個玉米單交品系，包括馬齒種及硬粒種間之三種組合，進行二期作之栽培密度（70×20公分、70×25公分及70×30公分）試驗。試驗結果顯示，不論春作或秋作環境下，單位面積之青割鮮重、乾物重及子粒產量，均隨栽培密度每公頃47,600株至71400株之增加而提高，密度處理對整株乾物率、果穗百分比及總營養消化率（TDN％）未有顯著影響。在不同密度處理下，單株鮮重及乾物重，在春秋作均以馬齒種×硬粒種及硬粒種×硬粒種優於馬齒種×馬齒種；整株乾物率、果穗百分比、總營養消化率及子粒產量，於春秋作下，三種粒型組合間略有變動，但概以馬齒種×硬粒種居首。同時考慮青割鮮重、乾物重、整株乾物率、果穗百分比、總營養消化率及子粒產量六項性狀，單交組合中以馬齒種×硬粒種或硬粒種×硬粒種較優，而栽培密度以70公分×20公分為宜。
A total of nine maize hybrids including dent and flint combinations were grown in three plant densities (70 × 20cm, 70 × 25cm, 70 × 30cm) at TART in spring and fall crop of 1988. Effects of plant density on forage and grain yield of maize were investigated. From plant density of 47,600 plant/ha to 71,400 plant/ha, significant increase of fresh weight, dry weight and grain yield per hectare was associated with increasing plant density. Whole-plant dry matter content, ear percentage and total digestable nutrient percentage (TDN) were less influenced. Among combinations, dent × flint and flint × flint were better than dent × dent for fresh and dry weight per plant. Various responses among kernel type combinations for whole-plant dry matter content and grain yield were found. However, in most cases dent × flint was the leading combination for these traits. It is suggested that the combination of dent × flint or flint × flint, and plant density of 70 × 20cm would be the best arrangement, if both forage and grain yield are concerned
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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