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31.
32.
Organic farming requires cultivars that are specifically adapted to this low input cropping system. Hence, organic farmers
and scientists joined in a participatory breeding approach to develop region-specific genotypes of spring faba bean for organic
conditions in Germany. A set of 49 genotypes with contrasting degrees of heterozygosity and heterogeneity was used in field
trials across five locations in Germany during 3 years 2004, 2005 and 2006. The material involved 18 inbred lines, their 18
polycross progenies, one blend of inbred lines, one blend of polycross progenies, one blend of hybrids and ten checks. Inbred
lines are uniform, thus giving the option to be specifically adapted; whereas the polycross progenies and synthetics (Syn-1;
predicted from the inbred lines and polycross progenies performance) are partly heterogeneous and heterozygous, thus giving
the option to evolve. Agronomic performance was assessed and a “personal appreciation” score of the material was assigned
to each genotype by each partner. This personal appreciation was strongly influenced by biotic and abiotic constraints faced
by the crop in each location and by the expected grain yield of the genotypes. Uniformity was apparently appreciated by organic
farmers. In all locations, the highest yielding inbred line yielded slightly better than the predicted highest yielding synthetic.
However, this slight disadvantage of the synthetic is very likely to disappear if the synthetic (Syn-1) is propagated during
successive generations. 相似文献
33.
Thirty-six lentil varieties were evaluated under organic and conventional environment for three consecutive years in order
to see whether the promising genetic material for an organic plant breeding program are different from those of a conventional
system. The genetic material studied originated from various countries. In the conventional trial plots standard cultural
practices (P mineral fertilization & pest control) were applied throughout the growing season, while in the organic ones no
fertilizers or pest agrochemicals were applied. Significant regression, but of low value, between grain yield ranking and
earliness or harvest index ranking was detected. Combined ANOVA indicated significant differences between genotypes, years,
environments and genotype × environmental interactions (GEI). It was observed that under conventional management most of the
genotypes had a higher yield compared to the organic one. The mean grain yield ranking of the genotypes in each of the environments
revealed that some of the genotypes occupied the same ranking position at both the organic and the conventional environment
(non-crossover GEI), while others exhibited a significant alteration in their ranking (crossover GEI) under the two environments.
Crossover GEI and non-cross over GEI revealed two types of lentil varieties. Varieties with specific adaptation and varieties
with broad adaptation. It was concluded that grain yield was in general higher when lentil varieties were grown under a conventional
environment compared to the grain yield produced under an organic environment. Yet, there are lentil genotypes with a higher
yielding ability under the organic management and therefore should be targeted by the breeder. 相似文献
34.
Organic farming has gained in importance in Germany during recent years. Therefore an increasing demand exists for varieties
with specific adaptation to this farming system. In the present study we therefore conducted comparative field experiments
with modern maize breeding materials under organic versus conventional farming conditions (ORG and CON, respectively) to estimate
quantitative genetic parameters needed for developing optimal breeding strategies and to investigate the perspectives of selection
for specific adaptation to ORG. Starting from two broad samples of elite germplasm, consisting of 178 flint and dent lines,
respectively, fractions of 11 flint and 11 dent lines were selected based on their testcross performance under ORG. A corresponding
set of lines was selected under CON. Testcross performance was evaluated in three regions of Germany and selection of superior
lines was practiced across two stages in 2004 and 2005, respectively. The specifically selected lines were crossed in a factorial
manner for production of experimental inter-pool single-cross hybrids which were field-tested under ORG and CON in two regions
in 2006. Average grain yields were about 16% lower under ORG than under CON. Variance components and entry-mean heritability
coefficients under ORG largely resembled those obtained under CON. Phenotypic correlations between ORG and CON were moderate
for grain yield and strong for grain dry matter content. No consistent estimates were obtained for the corresponding genotypic
correlation for grain yield. At the first stage of testcross selection no evidence of specific adaptation to ORG or CON was
observed whereas the factorial crosses tested in 2006 displayed distinct, yet non-significant, advantages when evaluated under
the respective target farming system. A small top fraction of hybrids showed outstanding performance under both ORG and CON.
The chances of detecting such broadly adapted genotypes are increased if ORG test sites are included in the regular testing
system. 相似文献
35.
不同有机酸对烤烟不同成熟度烟叶香气质量的影响 总被引:17,自引:0,他引:17
为了探讨有机肥对不同成熟度烟叶品质的影响,通过大田试验和室内分析相结合的方法,研究了有机肥分解产物的几种代表产物——苹果酸、油酸和腐殖酸,对不同成熟度烟叶石油醚提取物含量和香气物质含量的影响。结果表明,适熟采收时,有机酸对提高烟叶中石油醚提取物含量的影响不明显,但苹果酸和油酸能显著提高烟叶中主要香气物质的含量。过熟采收时,腐殖酸和油酸能提高烟叶中石油醚提取物的含量,同时能提高烟叶中糠醛、苯钾醛、茄酮、巨豆三烯酮和新植二烯等主要香气物质的含量,其中,腐殖酸效果最佳。 相似文献
36.
Jean-Paul Laclau Joseph Levillain Philippe Deleporte Jean de Dieu Nzila Jean-Pierre Bouillet Laurent Saint André Antoine Versini Louis Mareschal Yann Nouvellon Armel Thongo M’Bou Jacques Ranger 《Forest Ecology and Management》2010
Tropical plantation forests are meeting an increasing proportion of global wood demand and comprehensive studies assessing the impact of silvicultural practices on tree and soil functioning are required to achieve sustainable yields. The objectives of our study were: (1) to quantify the effects of contrasting organic residue (OR) retention methods on tree growth and soil nutrient pools over a full Eucalyptus rotation and (2) to assess the potential of soil analyses to predict yields of fast-growing plantations established on tropical sandy soils. An experiment was set up in the Congo at the harvesting of the first rotation after afforestation of a native herbaceous savanna. Six treatments were set up in 0.26 ha plots and replicated in 4 blocks, with OR mass at planting ranging from 0 to 46.5 Mg ha−1. Tree growth over the whole rotation was highly dependent on OR management at planting. Over-bark trunk volume 7 years after planting ranged from 96 m3 ha−1 in the treatment with forest floor and harvest residue removal at planting to 164 m3 ha−1 in the treatment with the largest amount of OR. A comparison of nutrient stocks within the ecosystem at planting and at the end of the rotation suggested that nutrient contents in OR were largely involved in the different response observed between treatments. OR management treatments did not significantly modify most of the nutrient concentrations in the upper layers of the mineral soil. Conventional soil analyses performed before planting and at ages 1 and 3 years were unable to detect differences between treatments despite large differences in tree growth. In contrast, linear regressions between stand aboveground biomass at harvesting and OR mass at planting (independent variable) showed that OR mass was an excellent predictor of stand yield (R2 = 0.99). A large share of soil fertility comes from organic material above the mineral soil in highly weathered sandy soils and OR mass at planting might be used in conjunction with soil analyses to assess the potential of these soils to support forest plantations. 相似文献
37.
介绍园林有机废物变栽培基质的原因、过程,产品应用实例,表明园林有机废物变栽培基质是节约型园林绿化发展的新途径,具有较好的社会效益和生态效益。 相似文献
38.
对城市已建绿地进行升级改造是城市更新的重要内容。广州火车东站南广场是城市新中轴线上的重要节点,为迎接第16届亚运盛会进行了绿地有机更新,取得了较好的效果。文章以此为例,分析探讨该项目的得与失,并总结阐述了绿地有机更新的一些理念、策略与特点,以期为未来城市绿地的升级改造实践提供有益参考。 相似文献
39.
中国有机农业发展现状、问题和对策 总被引:12,自引:0,他引:12
从中国有机农业发展的现状出发,详尽记述了有机农业发展在政策、技术等方面面临的困境,提出了现阶段有机农业和有机食品发展的对策,即从政策扶持、市场开拓、理论研究、技术推广等方面的宏观策略。 相似文献
40.
为明确有机栽培与常规栽培蔬菜的营养品质差异,以大白菜、生菜和黄瓜为研究对象,采用基质盆栽分析对比2种栽培方式下蔬菜营养物质(蛋白质、可溶性糖、总氨基酸)、维生素原类(胡萝卜素、维生素C、类黄酮)、风味物质(单宁、苹果酸、酒石酸)、矿质元素(Fe、Zn、Mn)以及硝酸盐与农药残留含量的差异。结果表明,有机栽培蔬菜的蛋白质、可溶性糖、氨基酸、类胡萝卜素、维生素C、类黄酮、苹果酸、Fe和Zn等有益营养物质的含量显著高于常规栽培蔬菜,相反,有机栽培蔬菜的单宁、Mn及硝酸盐含量显著低于常规栽培蔬菜,且3种常规栽培蔬菜中均检测到农药残留,其中大白菜和生菜的农药残留大大超过限量标准。由此可见,采用有机栽培方式种植的蔬菜不仅有益营养物质显著优于常规栽培蔬菜,而且其有害物明显低于常规栽培蔬菜。 相似文献