Production of interspecific hybrids between Glycine max and G. tomentella through embryo culture

Summary Interspecific hybrids have been obtained in an incompatible cross between Glycine max and G. tomentella through the in vitro culture of hybrid embryos. The percentage of successful pod setting in the crosses averaged 12.8% but there were marked differences depending on the soybean cultivar used as the female parent. Hybrid embryos at globular to heart stages were extracted from the embryo sac 15–25 days after pollination and cultured in vitro. Hybrid plants were successfully obtained by culturing the embryos on B5 medium supplemented with 0.1 mg/l IBA followed by culture on B5 medium supplemented with 0.1 mg/l TBA plus 0.25 mg/l 2-iP. The F1 plants resembled the wild male parent in growth form, but had an intermediate leaf shape between that of the parents.     

Sensitivity to Drought Stress of Three Soybean Cultivars During Different Growth Stages

Three soybean ( Glycine max L.) culivars, Lee-74, Wright , and Ra 401 , were subjected to 100 % (control), 75 %, and 50 % of field capacity during vegetative (VI), flowering (R2), and pod-filling (R4) stages in greenhouse and field studies. Stress applied at R2 significantly reduced the yield in the greenhouse, while in the field, the maximum reduction was observed when the plants were subjected to stress at R4. Stress during VI reduced the yield components less than stress applied during R2 or R4 stages in both studies. The pod number and seed weight were the yield components most affected by drought stress, and the number of seeds per pod the least affected. Yield stress index was significantly correlated with the yield and its components. The reproductive stage was clearly more sensitive to drought than the vegetative stage. The cultivar Lee 74 had the highest yield and the second highest yield stress index whereas the cultivar Ra 401 had the lowest yield.     

种粒大小选择对大豆种间杂交后代性状的影响

以两种类型大豆种间杂交组合Ｆ２至Ｆ４为材料,研究种粒大小集团选择效应及对其他性状的影响。表明：种粒大小是一个重要性状,大豆种间杂交后代随着向大粒方向选择,植株变矮,茎秆增粗,倒伏性降低,分枝数减少,产量性得以改善。在Ｆ２根据植株体表现进行种粒大小的分组定向选择,这种趋势能够有效地保持到高代。     

The Genomic Relationships Among Glycine soja Sieb. and Zucc., G. max (L.) Merr. and 'G. gracilis' Skvortz.

The objective of this study was to establish genomic relationships among G. sojii, G. max, and ‘G. gracilis’ based on cytogenetic analyses. All three species hybridized readily, though pod set was low (2.2 %—5.3 %); seeds produced viable, vigorous and totally fertile F, plants which were normal in meiotic pairing. This suggests that all three species-belong to one gene pool and should be considered as forms of one species.     

Pollen and coenocytic microspore germination in male-fertile and malesterilemsl soybean

Summary Light and fluorescence microscopy were used to study coenocytic microspore germination from male-sterile (ms1 ms1) soybean plants. Anther squashes from male-sterile plants revealed that a low frequency of natural coenocytic microspore germination occurred in male-sterile anthers of four independent lines; [ms1-North carolina (T260H),ms1-Urbana (T266H),ms1-Tonica (T267H), andms1-Ames (T268H)]. Abnormalities such as giant tubes, branched tubes, tubes with swollen areas, and multiple tubes were observed from coenocytic microspores from all four lines. The Urbana line, however, demonstrated a higher percentage of coenocytic microspore germination than did the other three lines. Flowers of the Urbana line from both malefertile and male-sterile plants, as well as gynoecia pollinated with coenocytic microspores from sterile plants, were used for in vivo studies. Pollen-tube growth appeared normal in male-fertile plants. In contrast, coenocytic microspore tubes rarely were observed in gynoecia from male-sterile plants or in gynoecia from malefertile plants that had been artificially cross-pollinated withms1 ms1 plants. Few tubes from coenocytic microspores were observed in the vicinity of the micropylar region. A low frequency of seed set was achieved in the greenhouse on Urbana male-sterile plants grown in the absence of male-fertile plants. Thus, we believe either that some gametes from coenocytic microspores are able to participate in fertilization at low frequency or that apomixis occurs inms1 ms1 plants.Joint contribution: Agricultural Research Service, U.S. Department of Agriculture, and Journal Paper No. J-12310 of the Iowa Agriculture and Home Economics Experiment Station, Ames IA, 50011 USA. Project 2471.     

Intersubgeneric Crossability in the Genus Glycine Willd.

In intersubgeneric crosses between wild perennial Glycine species of submenus Glycine and soybeans, Glycine max (L.) Merr., of subgenus Soja, all the putative hybrid pods aborted from 9 to 30 days after pollination (DAP). Spraying of 70 ppm gibberellic acid on hybridized gynoecia facilitated pod retention. Fluorescence microscopy revealed normal pollen germination and pollen tube growth in all the intersubgeneric crosses except in the G. cyrtoloba × G. max cross.     

基于近红外光谱技术的三种硬实种子无损鉴定

摘要：为探讨近红外光谱技术在鉴定种子硬实特性上的普遍性,该文采用近红外光谱法结合偏最小二乘法建立了大豆、苦豆子和决明子单粒种子硬实特性的定性分析模型,每种种子均选择120粒种子进行近红外定性分析,种子分为建模集、检验集2组,建模集80粒,检验集40粒,各组中硬实与非硬实种子的比例为1:1,比较了光谱重复次数、光谱范围以及不同建模样品的建模效果。结果表明：采用二次平均光谱所建模型的鉴别率优于单次光谱;大豆采用4 000～5 000 cm-1光谱范围,矢量校正预处理,主成分为8时,建模集与检验集鉴别率均在85%以上;决明子采用4 000～8 000 cm-1光谱范围,一阶导数预处理,主成分为4时,模型建模集与检验集鉴别率均在90%左右;苦豆子采用4 000～8 000 cm-1光谱范围,二阶导数预处理,主成分为8时,模型的建模集与检验集鉴别率均在95%以上。以上结果表明近红外光谱技术可以很好地应用于单粒种子硬实特性的判断,有助于硬实机理的深入研究。     

Nitrogen requirements associated with improved conservation tillage for corn production

Abstract

Excessive soil erosion and use of nitrogen fertilizer are costly to the Atlantic Coastal Plain corn (zea mays L., ’Funks G 4507') producer and both may serve to create environmental hazards. An in‐row chisel (36 cm deep) tillage method was compared with the standard 5 cm fluted coulter method for planting corn in premature wheat (Triticim aestivum L.) residues grown on an Orangeburg sandy loam (Typic Paleudult). Five orthogonal N levels ranging up to 440 kg of N/ha were used to determine an economic N optimum for each tillage method.

The in‐row chisel tillage method provides a possible yield advantage in the Atlantic Coastal Plain because of observed restricting soil layers within the normal corn rooting zone. The estimated profit‐maximizing quantities of N fertilizer were 262 and 295 kg of N/ha (234 and 263 1b of N/acre) for the fluted coulter and in‐row tillage procedures, respectively. Corn grain yields associated with these inputs were 9.6 × 10³ and 12.6 × 10³ kg/ha (153 and 200 bu/acre), respectively. The yield increase associated with in‐row chiseling through a 2.5 metric ton mulched surface is attributed to potentially improved rooting and more efficient water storage and use.     

大豆属Clycine亚属植物花粉形态研究

对大豆属Ｇｌｙｃｉｎｅ亚属中０个种的花粉进行了光学显微镜和扫描电镜的观察。发现多倍体材料的花粉大于二倍体的。并发现Ｇｌｙｃｉｎｅ亚属诸种花粉的形、萌发孔、外壁纹饰均存明显差异。     

Lime and Micronutrients Interaction in Soybean Genotypes Adapted to Tropical and Subtropical Conditions

Liming reduces acidity neutralizes aluminum (Al³⁺) and manganese (Mn²⁺) toxicities and increases calcium (Ca²⁺) and magnesium (Mg²⁺) concentrations in many acid soils of the world. However, it reduces the availability of other cationic micronutrients that are essential for plant growth. Therefore, an experiment was conducted in greenhouse conditions for assessing the effects of higher lime rates in foliar and grain boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) concentrations of 15 soybean genotypes [Glycine max (L) Merrill]. The lime rates were calculated to raise base saturation (V) to 40 and 70%. The soybean genotypes were classified as efficient and moderately efficient in lime-use, the most efficient cultivar was BRS 295RR, and the least efficient was TMG 7161RR and BMX Força RR. The lime rates × genotypes interaction was significant for foliar Cu. The grain the interactions were significant for B, Cu, Fe, and Mn concentrations. Foliar and grain B, Cu, Fe, Mn, and Zn concentrations varied significantly among the genotypes. The Ca and Mg concentrations in the leaf, grain, and soil showed a positive correlation with foliar B concentrations and a negative correlation with leaf and grain Cu, Mn, and Zn concentrations.