首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   30篇
  免费   6篇
农学   4篇
  4篇
农作物   4篇
水产渔业   3篇
畜牧兽医   19篇
园艺   2篇
  2020年   4篇
  2019年   1篇
  2018年   3篇
  2017年   1篇
  2015年   3篇
  2013年   1篇
  2011年   1篇
  2010年   8篇
  2009年   1篇
  2008年   1篇
  2007年   3篇
  2006年   2篇
  2005年   3篇
  2004年   2篇
  1998年   1篇
  1993年   1篇
排序方式: 共有36条查询结果,搜索用时 0 毫秒
31.
32.
In wheat, grain number is considered as the product of spike dry weight (SDW) and the number of grains per unit of SDW, that is an indicator of spike fertility (SF). The aim of this study was to determine the heritability of SF and the effect of early selection for high SF on its relationship with other spike yield components. Two field experiments were conducted in the south‐eastern Pampas (Argentina) with 400 F2 and F2:3 families obtained from two crosses between varieties with contrasting SF (PIG/SSN and B10/KCJ). Heritability estimates in PIG/SSN and B10/KCJ were, respectively, 0.60 and 0.51 by variance component analysis, 0.43 and 0.43 by F2 : F3 parent–offspring regression and 0.30 and 0.28 by realized heritability analysis. The existence of transgressive segregation (i.e. the occurrence of families with SF values that were more extreme than those of the parents) was observed. The top 25% F3 families with the highest SF had 12% more grains per spike, despite a 13% and 5% decrease in SDW per spike and weight per grain, respectively, than the remaining families. These results give support to the application of early selection for high SF.  相似文献   
33.
34.
Morphological and immunohistochemical studies carried out particularly around the level of the basal ganglia (BG) in birds, are reported and commented on. Our results showed, on paraffin embedded avian BG, both the histological features and the immunohistochemical findings on immunofluorescence distribution of some neuropeptides (especially Metenkephalin) in the striatal complex. By comparing our results of Metenkephalin immunoreactivity (Menkir) with the referred analogous ones of Substance P (SP) quoted in literature, we confirmed the strikingly similar labelling at the levels of the Lobus paraolfactorius (LPO) and Paleostriatum augmentatum (PA), in contrast with the very low immunoreactivity at the Paleostriatum primitivum (PP) levels. We were able also to demonstrate the strong MEnk-ir of the neurons of the Nucleus accumbens, Nucleus septalis and paraventricularis. All these findings are also in accord to the interpretation by many AA (Wynne and Gunturkun. 1995; Reinez et al., 1983). about the anatomical correspondence between the LPO-PA complex of birds and the caudate-putamen in mammals. Some MEnk +‘wooly like fibres’ described in our specimens in the PA (on the contrary reported in the Gpe segment of mammals) apparently escape these correspondence.  相似文献   
35.
Maize-soybean and sunflower-soybean intercrops have the potential for increasing yield per unit land area and time in fully mechanized farming systems. The objectives of this work were to measure the land equivalent ratio index of maize and sunflower intercropped to soybean, to assess the effects of plant density of its components, and to gain insight into ecophysiological processes affecting their yield determination. Maize-soybean and sunflower-soybean intercrops and their respective sole crops were grown at Balcarce, Argentina during two growing seasons. Treatments included a wide range of plant densities for sole and intercropped sunflower (2-9 plants m−2) and maize (4-12 plants m−2). Plants were harvested to determine shoot dry matter and grain yield per plot and at the individual plant level. Land equivalent ratio index (LER) increased 11% (mean of the two years) when plant density of sunflower was reduced from 6 to 3 plants m−2; and LER increased 5% (year 1) or it was maintained (year 2) when maize plant density was reduced from 8 to 4 plants m−2. Yield response to plant density of sunflower and maize influenced LER. The response to plant density of intercropped sunflower and maize grain yield followed the same pattern than that in a sole crop, and grain yield of intercropped sunflower or maize were lower than those for the sole crops at each plant density except at the lowest sunflower plant density. Yield reductions from sole crop to intercrop at each plant density averaged 20% and were associated (i) with lower intra-row spacing in the intercrop and (ii) with a lower shoot production rather than to a change in the dry matter partitioning to reproductive structures; in addition, detrimental effects of soybean over maize or sunflower yield were undetectable.  相似文献   
36.
Sunflower has potential in Mediterranean farming systems because of the modest auxiliary input requirement, appreciable productivity and quality of raw material. These aspects are affected by the interactions among genetic, environmental and agronomic factors, which have not been fully explored. Therefore, the effects of four water regimes as proportion of crop evapotranspiration (0%, 33%, 67%, 100%) on grain yield and its components, oil yield and grain lipid constituents, i.e. fatty acids (FAs), unsaponifiable matter (UM), phytosterol (Phy), policosanol (PC) and tocopherol (Toc) fractions of a standard and an oleic sunflower hybrids were assessed in a 2-year field experiment. The relationships between crop productive traits and oil quality features were also analysed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号