农林复合系统及其种间相互作用研究进展

种间互作已成为现代农林复合系统研究的核心内容之一,笔者综述了种间互作的机制、种间地上部分相互作用和种间地下部分相互作用研究进展,并对农林复合系统种间互作研究前景进行了展望。     

Population-specific QTLs and their different epistatic interactions for pod dehiscence in soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr.]

Pod dehiscence (PD) prior to harvest results in serious yield loss in soybean. Two linkage maps with simple sequence repeat (SSR) markers were independently constructed using recombinant inbred lines (RILs) developed from Keunolkong (pod-dehiscent) × Sinpaldalkong (pod-indehiscent) and Keunolkong × Iksan 10 (pod-indehiscent). These soybean RIL populations were used to identify quantitative trait loci (QTLs) conditioning resistance to PD. While a single major QTL on linkage group (LG) J explained 46% of phenotypic variation in PD in the Keunolkong × Sinpaldalkong population with four minor QTLs, three minor QTLs were identified in the Keunolkong × Iksan 10 population. Although these two populations share the pod dehiscent parent, no common QTL has been identified. In addition, epistatic interactions among three marker loci partially explained phenotypic variation in PD in both populations. The result of this study indicates that different breeding strategies will be required for PD depending on genetic background.     

Nutritional status and genetic variation in the response to nutrient availability in Pinus pinaster. A multisite field study in Northwest Spain

The low nutrient availability of the acidic and sandy soils of Galicia (Northwest Spain) is probably the main environmental factor limiting forest primary productivity in the area. These particular edaphic conditions could have imposed selective pressures on maritime pine populations leading to specific local adaptations.We first assessed the nutritional status of 22 young contemporary Pinus pinaster plantations in Northwest Spain, and then analysed the response to fertilization in three family × fertilization trials, and how this response varied across sites and genotypes.Growth of P. pinaster in Northwest Spain appeared to be largely limited by nutrient availability, where most of the plantations showed severe nutrient deficiencies, especially in P and Mg. According to these deficiencies, a strong positive response to nutrient additions was observed in the three trials, with height increments of up to 30% compared with the unfertilized control. However, the response to fertilizers was very variable from site to site, and in some cases did not agree with the foliar nutritional diagnosis. The response to fertilization was also significantly affected by pine genotype, suggesting that the plastic response to nutrient additions within each environment was under genetic control. However, the family response to nutrient availability was not consistent across sites, and no significant differences among families were observed for the RDPI plasticity index – a single index that summarizes the phenotypic change in multiple environments – when analysed across environments.The strong environmental component modulating phenotypic responses to fertilization could impose an important obstacle to evolve specific adaptations to the local edaphic conditions, as well as to artificially select genotypes adapted to different environments and silviculture regimes.     

Numerical Simulation of Microcrack Toughening in Particulate Composite

The crack tip region in an elastic composite can be divided into three different zones. The constitutive equations corresponding to these zones and the extent of the saturated damage zones are derived. The damage isotropy in the largest saturated damage zone is expressed by utilizing the Monte Carlo technique to create uniform distribution microcracks. The interaction between the main crack and microcracks can be evaluated by an alternating iteration scheme. In the assumption of a dilute concentration of microcracks, the interaction among microcracks is neglected, and the stress intensity factor produced by interaction between the main crack and each microcrack can be superposed. Two sources of loading are analyzed: one is for the main crack microcrack interaction under an applied remote load, and the other is for the main crack microcrack interaction accompanied by the relief of residual stresses on the microcrack surfaces. The results show that two sources of loading can shield the main crack tip, and microcracks behind the main crack tip can create the most shielding whereas the micro cracks ahead of the main crack tip play no role in shielding.     

玉米F2子粒的蛋白质含量及其与环境互作效应分析

以10个不同的玉米自交系为亲本,按照G riffing完全双列杂交设计配制成90个杂交组合,分别在河南浚县、郑州、南阳3个地点进行田间试验,对F2当代子粒的蛋白质含量进行分析.结果表明,地点和基因型各自之间玉米子粒蛋白质含量的差异均达到极显著水平,地点×基因型的互作效应达到显著水平;子粒蛋白质含量随纬度而变化,呈现北高南低的趋势;在所有杂交组合中,E 28×8085,E 28×Mo 17,E 28×K 12,8085×K 12,8085×昌7-2等组合子粒的蛋白质含量较高,平均为120 g.kg-1,尤其8085×昌7-2最高(129.6 g.kg-1),而丹340×郑58,许178×郑58,昌7-2×郑58等组合的较低,仅105 g.kg-1左右;正反交效应对F2当代子粒蛋白质含量的影响差异不显著.高蛋白品种必须与适宜的环境相结合才能充分发挥其优质的潜力.     

普通玉米蛋白质、淀粉和油分含量的遗传效应分析

【目的】研究玉米蛋白质、淀粉和油分含量的遗传主效应及基因型×环境互作效应。【方法】采用谷物种子性状遗传模型和统计方法,分析10个自交系及90个F1、F2杂交组合在两个种植地点的试验数据。【结果】蛋白质、淀粉、油分含量的遗传主效应方差（VG）和基因型×环境互作方差（VGE）分别占各性状总遗传方差（VG +VGE）的38.5%和61.5%、48.2 %和51.8%、48.2%和51.8%。在遗传主效应中,蛋白质、油分含量同时受控于种子和母体效应;淀粉含量以母体效应为主,种子（胚乳）效应次之;细胞质效应相对较小。在基因型×环境互作效应中,3个品质性状均以种子、母体×环境互作为主,未发现细胞质×环境互作。蛋白质含量以互作遗传力(h2GE）为主;淀粉、油分含量以普通遗传力（h2G）为主。【结论】3个品质性状都不同程度地存在种子（胚乳或胚）、母体植株和细胞质等3套遗传体系的遗传主效应及基因型×环境互作。其中,蛋白质含量主要受基因型×环境互作效应影响;淀粉、油分含量同时受遗传主效应和基因型×环境互作效应的作用。     

Non-parametric measures of phenotypic stability in chickpea genotypes (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.)

Multi-environment trials (MET) play an important role in selecting the best cultivars and/or agronomic practices to be used in future years at different locations by assessing a cultivar's stability across environments before its commercial release. Objective of this study is to identify chickpea (Cicer arietinum L.) genotypes that have high yield and stable performance across different locations. The genotypes were developed by various breeders at different research institutes/stations of Iran and the International Center for Agricultural Research in Dray Areas (ICARDA), Syria. Several statistical methods were used to evaluate phenotypic stability of these test chickpea genotypes. The 17 genotypes were tested at six different research stations for two years in Iran. Three non-parametric statistical test of significance for genotype × environment (GE) interaction and ten nonparametric measures of stability analyses were used to identify stable genotypes across the 16 environments. The non-parametric measures (Kubinger, Hildebrand and Kroon/Van der) for G × E interaction were highly significant (P < 0.01), suggesting differential responses of the genotypes to the test environments. Based on high values of nonparametric superiority measure (Fox et al. 1990) and low values of Kang's (1988) rank-sum stability parameters, Flip 94-123C was identified as the most stable genotype. These non parametric parameters were observed to be associated with high mean yield. However, the other nonparametric methods were not positively correlated with mean yield and were therefore not used in classifying the genotypes. Simple correlation coefficients using Spearman’s rank correlation, calculated using ranks was used to measure the relationship between the stability parameters. To understand the nature of relationships among the nonparametric methods, a hierarchical cluster analysis based on non weighted values of genotypes, was performed. The 10 stability parameters fell into three groups.     

A comparison of dry matter yield stability assessment methods for small numbers of genotypes of bermudagrass

No information is available on the efficacy of various nonparametric stability parameters when compared with GGE biplot methodology in assessing the stability of dry matter yield in bermudagrass (Cynodon dactylon L. Pers.) when a small number of genotypes is assayed. This study was conducted to compare the results of four nonparametric stability parameters developed by Huehn and Nassar ( , , , ), Kang’s rank-sum method and the GGE biplot method for five genotypes over 11 location–year environments at Oklahoma State University experiment stations. Results from analysis of variance procedures indicated highly significant levels of genotype-by-environment interaction (P < 0.01), which further indicated the need for stability analysis measures to be conducted. Results of the stability analysis indicated agreement among , , Kang’s rank-sum method, and the biplot method for the stability rankings of the genotypes and between these methods and the overall yield rankings of the genotypes. The and statistics were not in agreement with each other or any of the previously mentioned methods concerning the stability rankings of the genotypes. From examination of the formulae for the nonparametric statistics it was concluded that, when a small number of genotypes is assayed, the , , and statistics have the potential to be extremely sensitive and to produce misleading results. It was further concluded that for assessment of small numbers of genotypes the GGE biplot stability analysis method, augmented with Kang’s rank-sum method, would produce the most reliable estimates of genotype stability.     

Genotype × environment interaction for yield and reaction to leaf spot infections in groundnut in semiarid West Africa

Capitalizing on the yield potential in available groundnut germplasm, and high stability of kernel yield are important requirements for groundnut producers in semiarid environments. Forty-seven groundnut genotypes were evaluated from 2003 to 2005 at 4 locations representative of the Guinea and Sudan savanna ecologies in Ghana. The objectives were to assess genotypic differences in reaction to early and late leaf spot infections under natural field conditions, assess the extent of genotype × environment (G × E) interaction for kernel yield, and determine the relationship between yield potential and yield stability. Genotypes differed significantly in their reaction to leaf spot infections indicated by the area under disease progress curve (AUDPC). Genotypic AUDPC was negatively correlated with maturity period (P < 0.01), with kernel yield (P < 0.05) at each of the 3 locations in the Guinea savanna ecology but not in the Sudan savanna ecology and with each of four stability parameters (P < 0.05). High or low yielding genotypes were grouped based on Dunnett’s test at P < 0.10. High yielding groups had significantly low AUDPC, high biomass, high partitioning of dry matter for kernel growth, and were later in maturity compared to low yielding genotypes. Significant G × E interaction effect for kernel yield was dominated mainly by the lack of correlation among environments variance (76–78%) relative to the heterogeneity of genotypic variance component (22–24%). Stability of yield assessed through the among-environment variance, Wricke’s ecovalence, and Finlay-Wilkinson regression coefficient revealed that genotypes in the higher yielding group were relatively unstable compared to the low yielding group. Indicated by the Kataoka’s index of yield reliability, however, relatively unstable genotypes in the high yielding group are expected to be more productive even under assumptions of high risk aversion (P = 0.75–0.95) compared to the more stable, low yielding genotypes. The findings indicate that deploying these recently developed germplasm in semiarid regions in West Africa provides a better match to farmers’ risk-averse strategies compared with the use of existing earlier maturing cultivars.     

风作用甘蔗的动力学仿真模型

针对目前台风作用甘蔗动力学仿真研究中,风作用甘蔗的动力学仿真研究匮乏的问题,对甘蔗进行简化研究,利用测定的几何参数和CREO三维软件建立甘蔗几何模型,测定甘蔗物理力学特性参数,并建立了甘蔗材料模型。同时,建立了流场几何模型和材料模型,采用Hyper Mesh和LS-PrePost软件分别对甘蔗和流场模型进行网格划分,并定义边界条件和流固耦合控制参数;最后,利用LS-DYNA不可压缩流ICFD求解器和强耦合计算方法,考虑大涡模拟湍流模型,实现风与甘蔗的双向流固耦合作用,并对仿真模型精度进行物理验证。结果表明:该仿真模型的构建方法合理,可用于模拟风作用甘蔗的动力学过程,为台风-甘蔗和自然风-作物流固耦合系统动力学仿真建模提供依据。