Development of an interspecific Vigna linkage map between Vigna umbellata (Thunb.) Ohwi & Ohashi and V. nakashimae (Ohwi) Ohwi & Ohashi and its use in analysis of bruchid resistance and comparative genomics

To facilitate transfer of bruchid resistance to azuki bean (Vigna angularis) from its relatives an interspecific mapping population was made between rice bean, V. umbellata, and the related wild species V. nakashimae. The V. umbellata parent is completely resistant and V. nakashimae is completely susceptible to the bruchid beetle pests, azuki bean weevil (Callosobruchus chinensis) and cowpea weevil (C. maculatus). There is very low cross compatibility between V. umbellata and azuki bean. Therefore, V. nakashimae, that crosses with both V. umbellata and V. angularis without the need for embryo rescue, is used as a bridging species. A genetic linkage map was constructed based on an interspecific F₂ mapping population between V. umbellata and V. nakashimae consisting of 74 plants. A total of 175 DNA marker loci (74 RFLPs and 101 SSRs) were mapped on to 11 linkage groups spanning a total length of 652 cM. Segregation distortion was observed but only three markers were not linked to any linkage group due to severe segregation distortion. This interspecific genome map was compared with the genome map of azuki bean. Of 121 common markers on the two maps, 114 (94.2%) were located on the same linkage groups in both maps. The marker order was highly conserved between the two genome maps. Fifty F₂ plants that produced sufficient seeds were used for quantitative trait locus (QTL) analysis and locating gene(s) for C. chinensis and C. maculatus resistance in V. umbellata. The resistance reaction of these F₂ plants differed between C. chinensis and C. maculatus. Both resistances were quantitatively inherited with no F₂ plants completely susceptible to C. chinensis or C. maculatus. One putative QTL for resistance to each of these bruchid species was located on different linkage groups. Other putative QTLs associated with resistance to both C. chinensis and C. maculatus were localized on the same linkage group 1. Linked markers associated with the bruchid‐resistant QTL will facilitate their transfer to azuki bean breeding lines.     

Gene flow from transgenic roundup-ready soybean to wild soybean

A study was conducted in the field of the Institute of Vegetable Crops, Jiangsu province from July 2000 to August 2003. The transgenic roundup-ready soybean was sown in the middle of the field in a circular manner for 5 circles, with the distance of 3 m, from one circle to another. Then the wild soybean was planted in plots as the rays of the circles in 8 directions （N, E, W, S, NE, NW, SE and SW）, spaced every 5 m until 50 m. Each plot comprised 25 plants. In the second year, the wild soybean seeds from the first year were planted in the field together with the original wild soybean as check. Before flowering time, high concentrations of roundups （about 4-5 times of the normal dose） were sprayed on the plants and the surviving plants were identified. The leaves were taken to the lab for DNA extraction to determine the unique DNA for roundup-ready soybean （CTAB method）. About 2% of the plants survived, but some leaves were yellow. One plant of wild soybean was found to have the roundup-ready gene from the original roundup-ready soybean. The other surviving wild soybeans should also had some fragments of the roundup tolerance gene. However, the DNA bands were not very clear in the PCR map.     

A new method to select the drought resistance azuki bean germplasm

120 azuki bean germplasms from different regions of China were selected for drought-resistance. Results showed that there is a significant positive correlation between drought-resistance and photooxidation-resistance. So, the detecting technique for photooxidation-resistance should be suggested as a reference method to select the drought-resistance germplasms in azuki bean     

不同来源绿豆品种杂交F1农艺性状的遗传评价

将5个中国绿豆品种、2个泰国绿豆品种和1个韩国绿豆品种配制成34个不同的杂交组合,对其后代的农艺性状进行比较,并对各个组合的中亲和超亲优势进行了分析。结果显示,不同品种的杂交F1存在杂种优势,但不同组合之间的杂种优势强度不同,其中以CM5×K7、CM4×K7、CM3×K7之间的优势最强。     

Mapping of quantitative trait loci controlling powdery mildew resistance in Mungbean (<Emphasis Type="Italic">Vigna radiata</Emphasis> (L.) Wilczek)

Powdery mildew disease in mungbean is caused by the fungus, Erysiphe polygoni D.C. We identified two quantitative trait loci (QTLs) controlling resistance to the disease in a RIL population of 190 F₇ lines. The population was developed from the cross between a susceptible cultivar, “Kamphaeng Saen 1” and a resistant line, “VC6468-11-1A”. Reaction to the disease was evaluated for resistance in field and greenhouse conditions. Results from analysis of variance revealed that 15 SSR loci on three linkage groups (LG) associated with the resistance. Composite interval mapping consistently identified two QTLs on two LGs, qPMR-1 and qPMR-2, conferring the resistance. qPMR-1 and qPMR-2 accounted for 20.10 and 57.81% of the total variation for plant response to the disease, respectively. Comparison based on common markers used in our and previous studies suggested that qPMR-2 is possibly the same as the major QTL reported earlier using another resistant source. The SSR markers flanking and closely linked to qPMR-1 (CEDG282 and CEDG191) and qPMR-2 (MB-SSR238 and CEDG166) are useful for marker-assisted selection for mungbean resistance to powdery mildew.     

不同来源的小豆品种在中泰之间的遗传差异与聚类分析

通过对来自中国北部、中部和南部不同纬度地区的114个小豆品种在江苏南京和泰国农业大学的农艺性状进行研究。研究结果表明：与栽培在江苏相比，小豆品种在泰国热带地区表现为株高降低、生育期缩短，百粒重、每荚粒数、和单株产量均有所降低，但分枝数和每荚粒数变化不大。从不同来源的群体来看，来自中国北部的品种的农艺性状在泰国的变异系数大于中部品种，而南部品种引种至泰国后农艺性状的变异系数最小。通过对产量因子的相关分析表明，单株荚数对产量的相关系数最大（0．75）。而其它性状如分枝数（0．30）和每荚粒数（0．21）与产量的相关系数不大，而百粒重（0．07）对产量的相关系数最小。聚类分析的结果表明，以上114个小豆品种可划分为中国北部1、中国北部2、中部、南部4个大类。显示了北部品种之间有较大的遗传差异。     

生物柴油类植物的发展现状及在江苏省的应用前景

生物柴油是指通过植物油与甲醇进行酯交换制造的脂肪酸甲酯,是一种洁净的生物燃料,也称之为再生燃油。本文对目前江苏省生物柴油类植物的种植情况及适合江苏省种植的生物柴油类植物进行了总结,并对未来的发展前景作了简要分析。     

Removal of Lead from Contaminated Soils by Typha Angustifolia

A greenhouse study was demonstrated for removal of lead (Pb) from contaminated soil by the narrow — leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing various concentrations of Pb(NO₃)₂ (53.3, 106.7, 160, 213.3, and 266.7 mg Pb kg^-1 soil). Most lead was accumulated in roots and then transported to leaves. In soil contaminated with 266.7 mg kg^-1 of lead, the plants accumulated 7492.6 mg Pb kg^-1 dry weight in the roots and 167 mg Pb kg^-1 dry weight in the leaves. Yet, no growth retardation from lead was detected. T. angustifolia has high potential as a plant to clean up lead contaminated soil due to its vigorous growth, high biomass productivity, and because it is a perennial in nature. Further work is required to study on the iron plaque formation and its role in metal immobilization.     

Genetically manipulated pineapple: transgene stability, gene expression and herbicide tolerance under field conditions

Pineapple plants transformed with the bar gene for bialaphos resistance were evaluated for transgene stability, gene expression and tolerance to glufosinate ammonium, the active ingredient of the herbicide Basta^® X, under field conditions. Genetically modified plants of the cv. Phuket were micropropagated, rooted and established in a shade house before transfer to an experimental plot. Seven months after transfer to the field, plants were tolerant to 1600 ml/rai of the herbicide Basta^® X (stock concentration 15% w/v glufosinate ammonium), this being twice the dose recommended for field application of the herbicide. Genetically modified plants remained green and healthy following spraying with the herbicide. In contrast, non‐transformed pineapple plants of the same cv. became necrotic and died within 21 days of spraying with the herbicide at a reduced concentration of 800 ml/rai. Bar gene stability and expression in clonally‐derived plants were assessed by PCR, RT‐PCR and Southern analyses at 120, 210, 240, 270 and 380 days following transfer of the plants to the field. The bar gene was stable and expressed in transgenic plants throughout the duration of the trial. Fruit characteristics and yield were not affected by transgene introduction and expression. Transgenic plants tolerant to glufosinate ammonium should facilitate more effective weed control in pineapple plantations without damage to the crop.     

Inheritance of seed resistance to bruchids in cultivated mungbean (Vigna radiata, L. Wilczek)

Bruchid beetles or seed weevils are the most devastating stored pests of grain legumes causing considerable loss to mungbean (Vigna radiata (L.) Wilczek). Breeding for bruchid resistance is a major goal in mungbean improvement. Few sources of resistance in cultivated genepool were identified and characterized, however, there has been no study on the genetic control of the resistance. In this study, we investigated the inheritance of seed resistance to Callosobruchus chinensis (L.) and C. maculatus (F.) in two landrace mungbean accessions, V2709BG and V2802BG. The F₁, F₂ and BC generations were developed from crosses between the resistant and susceptible accessions and evaluated for resistance to the insects. It was found that resistance to bruchids in seeds is controlled by maternal plant genotype. All F₁ plants derived from both direct and reciprocal crosses exhibited resistance to the bruchids. Segregation pattern of reaction to the beetles in the F₂ and backcross populations showed that the resistance is controlled by a major gene, with resistance is dominant at varying degrees of expressivity. Although the presence of modifiers was also observed. The gene is likely the same locus in both V2709BG and V2802BG. The resistant gene is considered very useful in breeding for seed resistance to bruchids in mungbean.