1,720,960 research outputs found
(33(4):345-353)Mutagenic Efficiency of Sodium Azide on Rice Variety Tainung 67
No full text在pH 3 的磷酸緩衝溶液中，以3 及6 小時二種處理時問和0.0、1.0 、1.5 及2.0 mM 四種濃度，探討疊氮化鈉對臺農67 號的種根長、萌芽出土率、幼苗高、結實率和存活率等之影響。結果處理時問對幼苗高之效果無顯著差異外，其餘性狀皆與處理時間和濃度呈顯著的負相關，其中種根長和存活率對處理濃度呈現二次曲線迴歸關係，餘三種反應對處理濃度呈直線迴歸關係。五種反應中，種根長和結實率之相關最高。本試驗結論建議：疊氮化鈉處理時間不宜太長，種根長和結實率可作為實用處理時間的指標。
The presoaked seed of rice variety Tainung 67 were treated with sodium azide for 2 time periods, 3 and 6 hrs, at 4 concentrations, 0.0, 1.0, 1.5 and 2.0mM in a pH 3 potassium phosphate buffer solution for mutation breeding. Five related traits at M1 generation were observed, they were seminal root length, germination rate in greenhouse, seedling height, seedset rate and survival rate [percentage of plants that bore one or more seeds]. Except the seedling height on time periods of treatment, there existed a significantly negative correlation regression of all traits on the time duration and concentrations of treatment. The regressions of seminal root length and survival rate on the concentrations showed a quadratic nature, while other traits, respectively, showed a linear regression on the treated concentrations. The highest correlation was found between seminal root length and seedset rate of M1 generation. It is suggested to use a relatively short time period of treatment and to use the seminal root length and seed-set rate of M1 plant as the indicator to eveluate the mutagenic efficiency of sodium azide in rice mutation breeding
(34(3):237-242)Genetic Changes of Rice Variety Induced by Anther Culture
No full text水稻品種臺農67 號由花滿培養產生的綠苗（AC1S0）113 株中，有54.0 %是四倍體及單倍體；有44.2 %是二倍體：包括38.9%的正常植株，3.5%稔性降低，1.8%有粒型、葉型及葉綠素之突變。另有1.8%未抽穗無法鑑定。AC1S0個體內也有低頻度的遺傳變異發生。52個AC1S1 系統中有5.8%顯示低產，其餘均與原品種臺農67 號產量相似。系統內個體的結實率分離及降低使穗重減輕，因而引起低產。AC1S1系統除了結實率有突變外，株高、粒型、芒也有突變發生。共有69.8%的AC1S1系統保持與原品種臺農67 號同樣之性狀。
Among 113 anther-derived green plants (AC1S0) of rice variety Tainung 67, 54.0% were haploid, tetraploid and mixoploid; 44.2% were diploid, including 38.9% of the normal plants, 3.5% of low seedset plants and 1.8% of mutated types in the grain size, chlorophyll and. leaf shape. The remaining 1.8% did not produce panicle at harvest. There was a low frequency of genetic change occurred within an individual AC1S0 tiller. All AC1S1 lines gave an yield similar to those of Tainung 67 lines, except 5.8% that yielded distinctly lower. The low yield of these lines was caused by the segregation and lowering of seedset percentage and the panicle weight. In addition to the seedset percentage, mutations in the plant height, grain size and awn also appeared in the AC1S1 lines, of which 69.8% retained the characteristics of the original Tainung 67
(36(2):137-150)Genetic Analysis of Fertility Restoration in Cytoplasmic Male Sterile Indica Rice
No full text為尋求細胞質雄不稔性的稔性恢復基因之可用性及瞭解稔性恢復基因的遺傳行為，以便直接利用或供為轉移稔性恢復基因至其他優良品種或梗稻品種（系）之參考，將 Zhen Shan 97A (WA）、V20A (WA）兩個細胞質雄不稔品種和具有稔性恢復能力的臺農秈育172、178兩品系雜交，所得四個組合的F1、F2，調查其結實率、花粉率、莖基色、稃尖色、柱頭色、內外穎顏色等性狀。結果顯示：同屬 WA 型之兩個細胞質雄不稔母本與同一父本雜交所得F1及F2的稔性恢復之遺傳方式有相似之趨勢，但同一不稔系與不同父本雜交時之恢復稔性有不相似之遺傳行為。以酒井氏的遺傳變方估算稔性恢復基因對數，臺農秈育178可能最少具有四對顯性之稔性恢復基因，臺農秈育172可能至少具有三對顯性稔性恢復基因參與。這些稔性恢復基因推測具有互補及加性作用，即僅有一個顯性基因時無有效的恢復能力，即花粉稔性低於45%，有二個顯性基因時可恢復稔性45%至 91% 左右，而有三個或三個以上之顯性基因時，其稔性可完全恢復如父本者。根據此假設，以三對和四對基因的理論分離比與供試之四組 F2 集團的實測值比較，結果顯示花粉率的分離狀況與假設之條件相當符合，結實率的分離狀況亦大致符合。F2集團的花粉率與結實率有極顯著的相關，莖基色與稃尖、柱頭色有緊密的連鎖關係，重組合值介於 1.6%至8.1%之間，而莖基色與花粉率、結實率是互相獨立的，內外穎顏色與花粉率、結實率亦無可信賴的相關。
Two cytoplasmic male sterile varieties of indica rice, Zhen Shan 97A (P1) and V20A (P2) of WA type, were respectively crossed with two fertility restorer lines i.e. Tainung Sen Yuh 172 (P3) and 178 (P4), developed by TARI. The parents, F1 s and F2 s of four crosses, namely (P1/P3), (P1/P4), (P2/P3)and (P2/P4) were investigated for their pollen and spikelet fertilities, basal-leaf, apiculus, stigma and lemma-pelea colors. The pollen and spikelet fertilities of the F1 s and F2 s of the crosses having the same restorer male parent showed a similar tendency in the dominant nature of Rf genes and the pattern of segregation. In other words, different male restorers gave different patterns of seg-regation in these two traits, and different cms female parents gave the same pattern, probably due to their same origin of cytoplasm. At least 3 Rf genes in Tainung Sen Yuh 172 and 4 in Tainung Sen Yuh 178 were estimated by the genetic variance method proposed by Sakai (1952), however, under the assumption of complementary and addi-tive gene effects between these fertility restorer genes. One dominant Rf gene can give the pollen fertility of only 45%, two Rf genes are activ
(35(1):39-44)Ploidy Identification of Rice Plantlets Derived from Anther Culture by Stomatal Size
No full text為辨別花藥培養第一代（AC1S0）幼株的倍數性，以便早期行染色體倍加處理，取兩個水稻雜交組合之Fl，經花藥培養後所得AC1S0幼苗，以丙醯氛快速印模展開葉下表面，並觀察測量氣孔保衛細胞之長度。觀察氣孔的長度總共有16.86至31.36 μm之變域，平均長度為22.64 μm。然後以印模氣孔長度與AC1S0成株之倍數性相對照，發現單倍體株的氣孔長度有16.86至28.44 μm 之變域，平均為20.22 μm，雙倍體有17.67至31.36 μm之變域，平均為26.17 μm，兩者差異極顯著，證實以剛移出試管硬化後的AC1S0小株的氣孔保衛細胞長度，可以簡便而有效地辨出小株的倍數性，使單倍體小株可於早期倍加處理，以提高其在育種上的效率。
Stomatal size or guard cell length of the lower leaf surface of young rice plantlets derived from anther culture was investigated by the cyanoacrylate impression method.
Plantlets from two japonica rice hybrids that received anther culture were used. The guard cell length of their AC1S0 plantlets as a whole ranged from 16.86 μm to 31.36 μm with a mean of 22.64 μm before the identification of ploidy. Highly significant difference in stomatal size was detected between haploid and diploid plantlets classified according to the morphological characteristics of adult plants in the paddy field. Stomatal size of young haploid plantlets varied from 16.86 μm to 28.44 μm with a mean of 20.18 μm and those of diploids from 17. 67 μm to 31. 36 μm with a mean of 26.17 μm. The results support the possibility of identifying the haploid plantlets from anther culture by this method and of doubling their chromosome number to obtain dihaploid for advancing rapidly the breeding cycle
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
- …
