论文一Optimum crop density 最优栽种密度Grain amaranth 籽粒苋Combine yield 联合收割机产量Adapted genotype 采用的基因型Morphological characters 形态特征Shoot biomass 地上生物量root biomass 地下、根生物量Split plot design 裂区设计Stem diameter 茎粗Plant height 株高Harvest index 收获指数Plant population 植物种群Population pressure 种群压力Hand thinning 人工疏果Amino acid 氨基酸Grain yield 粮食产量Seed loss 种子损失Grain water content 粮食水分含量Unsaturated fatty acid 不饱和脂肪酸Inflorescence head 花序头Field study 田间试验Analysis of variance=ANOVA 方差分析Stationary ear thresher 固定脱粒机error term 误差项Non-linear regressions非线性相关关系Significant effect 显著差异、效应Multiple comparisons of means 均数多重比较Soil level 土壤水平Emergence rate 出苗率Interspecific competition 种间竞争Intraspecific competition 种内竞争Uniform distribution 均匀分配Optimum crop densities for potential yield and harvestable yield of grain amaranth are conflicting 最佳密度对苋科植物的潜在产量和最佳产量是否有影响仍有争议AbstractGrain amaranth is a C4 crop with potentially increasing cultivation area. Yet, no standards exist for optimum plant density. The aim of the study was to determine howcrop density affects amaranth morphology, biological grain production and combine yield.A field experiment was conducted under semiarid conditions (9.8 °C, 546 mm) in Eastern Austria during 2002, 2004 and 2005. Two adapted genotypes (Amaranthus cruentus, Amaranthus hypochondriacus) were established at five densities (8, 17, 35, 70, 140 plants m−2) by hand thinning at a row spacing of 37.5 cm. The obtained densities at harvest averaged across years and genotypes were 8, 15, 32, 54, 89 plants m−2. Plant samples were hand-harvested for the determination of morphological characters, grain and total shoot biomass. Subsequently a plot combine was used for harvesting the plots. Rising plant population reduced the number of branches an d the stem diameter from 11 plant−1 and 19 mm for the lowest density to 2 plant−1 and 8 mm for the highest density, respectively. Overall plant height decreased with rising density except for 2004 when plant height was highest at medium densities. Grain production and seed number decreased in parallel from 35 g and 48,000 seeds plant−1 to 3 g and 4800 seeds plant−1, respectively. Thousand seed weight was not affected. Grain yield slightly decreased from 270 g m−2 at densities of 8 or 17 plants m−2 to 240 g m−2 at densities of more than 70 plants m−2. Total shoot biomass did not respond to crop density, thus the harvest index decreased from 0.36 for 8 plants m−2 to 0.29 for 140 plants m−2. Rising density reduced seed losses during combine harvesting from 62 t o 16 g m−2. Consequently, combined grain yield was similar among plant populations and ranged between 220 and 240 g m−2. Grain water content at harvest decreased from 31% for the lowest density to 27% for the highest density. In conclusion, amaranth stands produce highest grain yields at low plant populations. However, for combine harvesting, a plant density of more than 50 plantsm−2 is most suitable. Small plants with thinner stems, reduced branch number and low grain moisture facilitate mechanical harvest and reduce seed losses.籽粒苋是一种种植面积潜在增加的C4作物。
然而,尚无最佳种植密度标准的存在。
这项研究的目的是确定作物密度如何影响苋属植物形态、生物粮食生产和组合收益率。
2002年、2004年和2005年，一个田间试验(9.8°C,546毫米)在奥地利东部半干旱条件下进行了。
两个适应基因型(繁穗苋, 千穗谷)被建立在通过37.5厘米行距上人工间苗而来的5个密度梯度(8,17,35,70,140株/m−2)上。
不同基因型和密度的年均收获量为8,15,32,54,89株/ m−2。
为了确定形态特征、谷物和总生物量的关系，植物样本是人工收获。
随后一个小区联合收割机被用来收获实验小区的作物。
植物种群的增加减少了分支的数量和茎直径，从最低密度的11个分支/株和19毫米茎干直径到最高密度的2个分支/株和8毫米茎干,分别。
总的来说，作物株高是随着密度增加而降低的，除了2004年最高株高出现在了中等密度水平。
粮食产量和种子数减少并行，分别从35 g和48000个种子/株植物到3 g和4800个种子/株植物。
千粒重不受影响。
籽粒产量略有下降，从8或17株/ m2密度的270克/ m2 到密度超过70株/ m2的240克/ m2。
目标生物总量没有回应作物密度,尽管收获指数从8株/ m2的0.36 下降到140株/ m2的0.29。
密度增加在种子联合收获上的损失从62 g/ m2减少到16g/m2。
结果, 在不同植物种群的联合籽粒产量是相似的并介于220~240克/ m2。
收获期粮食水分含量在从最低密度的31%下降为最高密度的27%。
总之,苋类作物较低的植物种群产生最高的粮食产量。
然而,对于联合收割,植物密度超过50株/ m2是最合适的。
茎细,减少分支数和较低的粮食水分的小植物能促进机械收获和减少种子的损失。
ConclusionRising population pressure drastically reduced stem diameter, number of branches per plant, number of seeds per plant as well as grain yield per plant, while total aboveground biomass yield was not affected. Number of plants per area compensated for reduced yield per plant to some extent, but harvest index and consequently biological grain yield declined with rising density. As seed losses also decreased, the effect of crop density on combined grain yield was not significant. Thus, for farming practice crop stands of more than 50 plants m−2 can be recommend with regard to stem diameter, plant height, seed losses and grain moisture which are significant parameters for combining suitability.种群增长的压力大幅减少茎杆直径,每个植株的分支数,每个植物的种子数量以及每棵植株的谷物产量,而总的地上部生物量产量没有影响。