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131.
This paper reports the effects of irrigation amount and partial rootzone drying (PRD) on water relations, growth, yield and wine quality of Vitis vinifera cv. ‘Tempranillo’ during two consecutive years in a commercial vineyard with a deep, light-clay soil located in Requena, Valencia, Spain. Partial rootzone drying applied at two amounts (100% and 50% of the estimated crop evapotranspiration), was compared to conventional drip irrigation, and also to rainfed vines. Results showed that the effects of irrigation amount on yield and wine quality were different between years. In 2003 with low yield values (around 6.3 t ha−1) irrigation did neither affect grape production nor wine quality. However, in the following year, with much higher general yield (17 t ha−1), the high irrigation dose increased yield by 30% compared to rainfed vines and it also increased must total soluble solids and wine alcohol content. In both seasons, PRD did not significantly affect physiological parameters, nor growth, yield or fruit and wine quality, when compared to the same amount of water applied by conventional drip irrigation. Overall these results suggest that, under our experimental conditions, it was the irrigation amount rather than the system of application what affected vine performance, indicating the difficulties of successfully employing the PRD type of irrigation with a drip system in heavy and deep soils. 相似文献
132.
The use of plant water status indicators such as midday stem water potential (Ψstem) and maximum daily trunk shrinkage (MDS) in irrigation scheduling requires the definition of a reference or threshold value, beyond which irrigation is necessary. These reference values are generally obtained by comparing the seasonal variation of plant water status with the environmental conditions under non-limiting soil water availability. In the present study an alternative approach is presented based on the plant’s response to water deficit. A drought experiment was carried out on two apple cultivars (Malus domestica Borkh. ‘Mutsu’ and ‘Cox Orange’) in which both indicators (Ψstem and MDS) were related to several plant physiological responses. Sap flow rates, maximum net photosynthesis rates and daily radial stem growth (DRSG) (derived from continuous stem diameter variation measurements) were considered in the assessment of the approach. Depending on the chosen plant response in relationship with Ψstem or MDS, the obtained reference values varied between −1.04 and −1.46 MPa for Ψstem and between 0.17 and 0.28 mm for MDS. In both cultivars, the approach based on maximum photosynthesis rates resulted in less negative Ψstem values and smaller MDS values, compared to the approaches with sap flow and daily radial stem growth. In the well-irrigated apple trees, day-to-day variations in midday Ψstem and MDS were related to the evaporative demand. These variations were more substantial for MDS than for midday Ψstem. 相似文献
133.
134.
发芽率是玉米种子质量检验的重要指标,种子发芽率低会影响农业作物单产。影响玉米种子发芽率的因素有种子成熟度、病虫害、水分、温度等。通过采取选择合适品种、加强田间管理、采用科学制种技术等措施,可以提高玉米种子发芽率,保证玉米稳产、高产。 相似文献
135.
介绍近几年黑龙江省农机购置补贴工作的实施措施和成效,指出购机补贴工作中存在的问题.并对今后的农机购置补贴工作提出几点建议,以促进全省农机结构更加趋向合理化,推动农业机械化水平进一步提高,实现粮食增产、农业增效、农民增收。 相似文献
136.
Information about reproductive season, size at sexual maturity and size-dependent reproductive potentials is important for
efficient resource management. Such information is necessary to determine seasonal closures and minimum legal size limits.
To conserve resources of coconut crab Birgus latro, which are in danger of extinction due to excessive exploitation, their reproductive season, female size at functional maturity
and relationship between female size and reproductive potentials were investigated. The reproductive season started in early
June and ended late August, and females with higher reproductive potentials showed a tendency to spawn early in the reproductive
season. The prohibition of exploiting the resources during the reproductive season, especially early in the season, would
be appropriate for sustainability of high reproductive outputs. Fifty percent of investigated females matured functionally
at 24.5-mm thoracic length (TL). However, the size at which all females reached functional maturity was 32.3 mm TL, and there
was a wide variation in the size of functional maturity among individuals. We must determine minimum legal size by taking
the variation into account to allow all individuals to mate at least once before they are caught, which may prevent serious
depression in reproductive rate and genetic diversity. 相似文献
137.
提出了一种改进的积因子层次分析方法—积因子位次赋值数据求权重法,该方法采用算术平均数赋值代替专家打分,最大程度的避免了主观判断可能造成的决策失误。用该方法对影响黑龙江省粮食生产潜力的17个因素进行排序,结果与实际情况较吻合。 相似文献
138.
G.J. Rebetzke M.H. Ellis D.G. Bonnett A.G. CondonD. Falk R.A. Richards 《Field Crops Research》2011,124(3):323-331
The green-revolution Rht-B1b and Rht-D1b dwarfing alleles are usually associated with increased wheat yields but are linked to reduced early growth and poor emergence if sowing conditions are unfavourable. Other dwarfing genes are available but not used in commercial breeding. The Rht13 bread wheat donor, Magnif M1, produces uniquely short peduncle and penultimate internodes to reduce plant height. A set of near-isogenic (NILs) and recombinant inbred (RILs) lines varying for height were developed from the cross of Magnif M1 and the Rht8c-containing Chuan-mai 18, and evaluated for a range of agronomic characteristics across favourable environments. Reductions in plant height were associated with increased grain number (r2 = 0.35**) and harvest index (r2 = 0.62**) in the NILs. Reduced-height RILs containing the Rht13-linked, Xgwm577M microsatellite marker were significantly shorter, produced greater biomass, yield and harvest index, and increased spike and grain number than lines without the marker. Approximately 74 and 7% of the total phenotypic variance in plant height was accounted for by allelic differences in Xgwm577 and Rht8 loci, respectively. The peduncle and penultimate peduncle internodes of Rht13-containing lines were proportionately shorter than Rht8c-containing sibs and lines containing the Rht-B1b dwarfing allele. The unique height-reducing phenotype, increased grain number and yield associated with Rht13 indicate considerable potential for use of this dwarfing allele for improving wheat performance. 相似文献
139.
为了阐明不同水分条件下氮、磷对不同基因型小麦的水分生理指标的作用及其变化趋势,试验逸用6个不同基因型的小麦进化材料,研究了拔节期各基因型小麦的叶片保水力、叶水势、叶片膜透性与气孔导度。结果表明,当土壤水分充足时,施肥会提高叶片保水力、叶水势,降低叶片膜透性,增加二倍体小走的气孔导度,而降低六倍体小走的气孔导度。在水分胁迫下,施肥会提高叶片保水力,降低叶水势、叶片膜透性和气孔导度;而且随小麦染色体倍性从2n→4n→6n的进化方向,小麦叶片保水力、叶水势、叶片膜透性均先降低,然后又升高。 相似文献
140.