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1.
We investigated how the responses of grain yield of maize to planting density depended on planting pattern (twin row, TR; narrow row, NR; narrow twin row, NTR; compared with conventional row (CR) cultivation) over 2 years using cultivars with relative maturity of 93 days. Grain yields were higher in order of NTR ≥ TR ≥ NR ≥ CR in all planting densities. Changes in grain yield and total dry matter yield with planting density followed significant negative quadratic regression curves in all planting patterns, increased with dense planting from 9.7 to 10.4 planting density and decreased thereafter. Changes in number of grains per ear and hundred grain weight with planting density followed significant negative linear regression in all planting pattern, and number of grain per ear, hundred grain weight and harvest index decreased with dense planting. The quadratic coefficient of the quadratic regression model, which indicates the changeability of the planting density response of grain yield, was lowest for NTR, followed by TR, NR and CR. The decline in number of grains per ear in response to increasing planting density for different planting patterns was NTR ≤ TR ≤ NR ≤ CR. The planting density response of total dry matter yield closely follows that of the grain yield in all planting pattern. But decrease in harvest index due to increased planting density for different planting patterns was lowest for NTR, followed by TR, NR and CR. Considering the relationship of grain yield to their related traits, the improved stability of grain yield for the specific planting patterns from the fact that the decline in number of grains per ear for different planting patterns is NTR < TR ≤ NR < CR. The specific planting patterns moderate the decline in harvest index and number of grains per ear with increasing planting density by enabling the maintenance of greater inter‐individual distance a given planting density. 相似文献
2.
A field experiment was conducted in a randomized block design with three replications over 2 years to evaluate the effect of wheat cultivar and dual inoculation of Azotobacter chroococcum (Azc) and arbuscular mycorrhiza fungi (AMF, Glomus fasciculatum) on root characters and AMF infection in three crosses of wheat. The experimental material comprised four wheat parents, WH‐147, WH‐157, WH‐542 and PBW‐175, and three F1 crosses, WH‐147 ×WH‐157, WH‐147 × WH‐542 and WH‐147 × PBW‐175. Comparison of treatment averages, i.e. control (mineral nutrients 60 kg N + 30 kg P2O5 + 12.5 kg ZnSO4 ha?1, as in other two treatments), AMF and AMF + Azc, revealed that inoculation of Azc led to an increase in AMF infection in roots. Maximum root biomass was obtained in F1 hybrids WH‐147 × WH‐157 in the AMF treatment and in WH‐147 × PBW‐175 receiving AMF + Azc. Total root length and AMF infection of roots was maximum in WH‐147 × PBW‐175 for all the treatments during both years. A positive association between AMF infection in roots and Azotobacter survival in the rhizosphere was apparent. Similarly, maximum A. chroococcum counts were observed 80 and 120 days after sowing in the AMF + Azc treatment in cross WH147 × PBW175. 相似文献
3.
Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. Cultivar-related differences in grain yields were observed in treatments with low and medium N supply. High doses of N supply resulted in grain yield adjustment or grain yield advantage for cv. Toronto. The results of this study revealed a consistent, genotypic pattern in response to N fertilization in spite of strong seasonal effects. Systematic modifications in canopy growth rates in response to N supply were of particular relevance and a main factor for differences in tillering intensity resulting in modified stand densities. In the present study, cultivar differences in spike development and interactions with N supply related more to abortion than to initiation processes for number of spikelets and number of flowers per spikelet. High grain density (grains per m2) of cv. Toronto was evident during reproduction stages even under conditions of medium N supply. However, decreased growth rates during the later part of grain filling in combination with low 1000 grain weight, which was barely modified by N fertilization, allowed only partial utilization of this potential. It is assumed that sink limitations were of particular relevance for grain yield development in cv. Toronto, while cv. Batis combined a less intense response to N supply with more stability in the development of grain yield components. 相似文献
4.
青岛梅园的建设及梅花品种的搜集与选育 总被引：1，自引：2，他引：1
在简介青岛梅园这一北方“新星”后,着重报道了其在建园中完成的两项科研成果,即①梅园快速规划设计与施工;②梅花品种的搜集、整理与新品种选育 相似文献
5.
H.-P. Piepho 《Journal of Agronomy and Crop Science》1998,180(4):193-213
The stability of yield is an important characteristic to be considered when judging the value of a cropping system relative to others. In the context of agricultural research, the analysis of yield stability has been largely confined to multienvironment trials of crop cultivars. This review emphasizes that methods for comparing the stability of cultivars can also be used for comparing different agronomic treatments in general, of which cultivars are but a special case. Throughout the paper, different agronomic treatments are referred to as cropping systems. Some of the methods useful for stability analysis of cropping systems are discussed and a brief review of applications of these methods is given. The paper puts different stability measures into a unifying mixed model perspective. 相似文献
6.
F.N. Green R. Baur Morellen Thomson Lesley McCarthy 《Genetic Resources and Crop Evolution》1997,44(6):491-493
Genetic lines and example cultivars are used as markers to define variation when describing or evaluating wild or cultivated germplasm. Occasionally genotypes previously described in the literature are no longer available. This was thought to be the case for chartreuse skin colour in Onion. However, registration authorities undertaking Distinctness, Uniformity and Stability tests recently observed this skin colour in the cultivar Greenella and have provided seed to a genebank for long-term conservation. This characteristic is suitable both for use as a genetic marker and as an example cultivar for describing Onion skin colours. 相似文献
7.
8.
以花生四大类型栽培种为母本,４个人工合成双二倍体野生种杂种为父本组成１６个杂交组合,结果表明：１６个组合的花果率和针果率变化范围都很大,显示各组合间杂交亲和力有较大的差异。野生种杂交种中以（Ａｒａｃｈｉｓ．ｃａｒｄｅｎａｓｉｉ×Ａｒａｃｈｉｓ．ｂａｔｉｚｏｃｏｉ）Ｆ２为父本与栽培种杂交的亲和力最大;而栽培种类型中以天津豆（普通型）为母本与野生种杂种杂交的亲和力最大;但珍珠豆型与４个野生种杂种之间杂交的亲和力差异最小。１６个组合中有许多授粉花不能形成果针而相互间表现不同差异。果针形成正常荚果有４种败育现象。 相似文献
9.
为探明高效杀菌剂用药量和防治时期对水稻稻曲病的防治效果及防治机理,研究了2种杀菌剂的3个用药量和8个用药时期对籼粳交水稻品种‘甬优12’稻曲病的防效。结果表明,在推荐用量范围内对稻曲病防治效果较好,随着用量上升防效有提高趋势,但除喜奥300 g/hm~2用药量防效显著低于其他处理外,用药量不是影响防效的关键因素;2种杀菌剂在破口前20天就开始具有一定防效,越接近开花期,防效越明显,破口后防效开始呈下降趋势,其中喜奥在齐穗期后防效下降较为迅速。因此认为,稻曲病在侵染‘甬优12’的关键时期是在开花期,可选用长效高效杀菌剂,于破口前进行防治。 相似文献
10.