Evaluation of Cassava Cultivars for Resistance to Cassava Mosaic Disease and Yield Potential in Central African Republic

Eleven cassava genotypes were tested against cassava mosaic disease (CMD) and compared to a local susceptible cultivar in field conditions from June 2011 to July 2012 in Central African Republic (CAR) at two sites representative of the savanna (Damara) and forest (Pissa) zones of the country. The mean number of whiteflies observed on plants varied among genotypes within each site, but was found nearly three times higher at Damara than at Pissa, resulting in a CMD incidence nearly five times higher at Damara than at Pissa. However, no relation was observed between the number of insect on the plants and the level of susceptibility/resistance of the genotypes. The difference of disease pressure between the two sites revealed high level of resistance in several genotypes, while some other ones indicated rather only a partial resistance. Nevertheless, none of the genotypes tested was found immune, in the end, the virus being detected at least in one site in every genotype, including those ones presenting no symptoms in both sites. The impact of CMD on yield components was assessed on the local susceptible check and three partially resistant genotypes, showing that the disease has no significant effect on the tuberous roots number as well as their weight in both sites. The yield potential varied among different genotypes and between the two sites, the mean number of tuberous roots as well as their mean weight being higher in Damara than in Pissa. This study identified highly resistant genotypes such as ‘Gabon’ that performed well in both sites, and ‘91/02322’ that was symptomless and presented a yield potential equivalent to the local check. These genotypes could be distributed to growers with the main advantage to be resistant to CMD and, therefore, reducing the risk to spread sources of inoculum all over the cassava cropping areas in the country.     

Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B colonisation and leaf morphology relationships in upland cotton cultivars

Cultivars of upland cotton, Gossypium hirsutum L., are widely grown throughout the world for fibre production. They are also good reproductive hosts for Bemisia tabaci (Gennadius) biotype B. We studied the relationships between cotton leaf morphology and whitefly population densities in eight United States Deltapine and six Australian cotton cultivars and breeding lines at Holtville, California, in 1996. Results showed that okra-leaf cultivars and lines were colonised with fewer whitefly adults, eggs and nymphs compared to normal-leaf cultivars. The distance from underleaf surfaces of cotton leaves to the centres of nearest minor vascular bundles was negatively correlated with whitefly adult, egg and nymphal densities on leaves for all genotypes with the exception of the Australian breeding line 89013–114. Our results suggest that okra-leaf and distance from underleaf surfaces to the centre of nearest minor vascular bundles of cotton leaves are genetic traits that have potential for breeding whitefly-resistant upland cotton cultivars.     

西藏小麦品种和引进品种在拉萨种植的品质比较

为了给西藏优质小麦生产的品种利用提供依据 ,1998～ 2 0 0 0年 ,用 7个西藏春小麦品种和 4个引进品种在拉萨进行了 3年春播试验 ;1998～ 2 0 0 1年 ,用 2个西藏冬小麦品种和 3个引进品种进行了 3年秋播试验。结果表明 ,西藏品种的蛋白质含量、湿面筋含量、沉降值明显低于引进品种。西藏品种属于弱筋小麦品种。西藏优质专用小麦生产中的品种利用途径是 :加强中筋小麦的生态育种 ;引进内地强筋小麦品种     

Comparison of suitability of RAPD and ISSR techniques for determination of strawberry (<Emphasis Type="Italic">Fragaria ×</Emphasis><Emphasis Type="Italic">ananassa</Emphasis> Duch.) relationship

Two PCR-based techniques, RAPD and ISSR, were utilized for determination of genetic relationship of 24 strawberry cultivars used in breeding program at the Research Institute of Pomology and Floriculture in Poland. Polymorphism of investigated genotypes was observed in reactions with 23 out of 48 tested RAPD primes and 41 from 90 tested ISSR primers. Relationship, determined on the base of polymorphic products analysis and showed in the form of dendrograms (UPGMA percent method), was generally similar for both techniques, although similarity values based on ISSR data were higher than those based on RAPD. The parallel use of two data sets seems to allow for precise estimation of cultivars relationship and diminishing mistakes connected with methods' technical limitations.     

Identification and characterization of microsatellite loci in the common fig (Ficus carica L.) and representative species of the genus Ficus

We developed microsatellites in fig (Ficus carica L.). A TC and TG‐enriched genomic library was screened, and after sequencing, primers were designed for 20 microsatellites. Eight primer pairs produced amplification products that were both interpretable and polymorphic in 14 fig cultivars and two French wild‐growing populations of F. carica (n₁ = 9 and n₂ = 10). Number of alleles per locus ranged from three to six. Except for one microsatellite locus, the observed heterozygosity was higher than the expected value. The F. carica microsatellites gave amplification products in 17 other Ficus species in 86% of the cases.     

不同抗性小麦品种上麦红吸浆虫幼虫的空间分布型与理论抽样数

【目的】为了解小麦品种抗性对麦红吸浆虫Sitodiplosis mosellana(Géhin)幼虫在麦穗上空间分布型的影响,为科学调查提供合理的抽样依据。【方法】2015年5月采用剥穗调查法对陕西省周至县试验田种植的4个抗虫和4个感虫小麦品种麦红吸浆虫幼虫危害进行调查,应用6种聚集度指标和Iwao M*?m回归法综合分析了幼虫在抗性不同小麦品种上的的空间分布结构。【结果】幼虫在抗、感小麦品种整穗及麦穗上、中、下部位上空间分布型一致,均呈聚集分布,但在抗虫品种上聚集强度大于感虫品种;抗、感小麦品种上分布的基本成分均为个体群,个体间相互吸引。聚集均数λ分析表明,幼虫在抗性较强品种上的聚集主要由小麦穗部化学物质和形态结构等环境因素引起,感虫品种上则由环境因素和成虫的产卵习性共同作用所致。幼虫在抗、感小麦品种上的发生趋势一致,均是上部发生最重,中部次之,下部最轻。根据Iwao回归法中的分布型参数,确立了幼虫在不同虫口密度和允许误差条件下的理论抽样数。【结论】麦红吸浆虫幼虫在抗性不同小麦品种上均呈聚集分布,调查时应根据当地栽培品种平均虫口密度选择适宜的抽样数量。     

Unused genetic resources: a case study of Polish common oat germplasm

Landraces and old, obsolete cultivars are a rich source of diversity and could become important and easy‐to‐use germplasm resources for breeding. They are characterised by yield stability, broad adaptation, tolerance to diseases and a greater competitiveness in the presence of weeds. The main objective of this study was to estimate and compare the genetic diversity among and within landraces, old cultivars and modern cultivars of common oat. Inter simple sequence repeats were used to study the genetic diversity of 12 modern Polish cultivars, 23 old Polish cultivars, 19 native landraces and 5 contemporary European cultivars. The results indicated a low amount of diversity among Polish modern cultivars, but an even lower diversity among old Polish cultivars, as well as large differences between these two gene pools. As expected, the landraces were the most diverse group and showed the highest internal variation. The landraces and old cultivars might serve as sources of useful alleles that have never been used in breeding. Additionally, it was possible to identify errors and inconsistencies in the passport data of gene‐bank accessions. These results can be applied to the maintenance and management of gene‐bank collections.     

Isolation and characterization of microsatellite loci from Macadamia

Thirty‐three microsatellite loci were isolated for the Australian rainforest tree Macadamia integrifolia. Genotyping across a test panel of 43 commercial cultivars generated an average polymorphic information content of 0.480. Five loci showed no polymorphism across cultivars. Significant linkage disequilibrium was detected in 10 pairwise comparisons, including two pairs of loci identified from the same clone sequence. The 33 microsatellite loci represent a significant tool for genome mapping and population genetic studies.     

Study on the vesicular-arbuscular mycorrhiza of three cultivars of potato (Solanum tuberosum L.)

Summary The establishment and development of vesicular-arbuscular mycorrhizal (VAM) fungi were studied in three cultivars of potato, which differed in susceptibility to Late blight, in a field experiment on a lateritic sandy-loam during two growing seasons (1980 and 1981). The cultivars SSC 1174 (highly resistant) and Kufri Jyoti (resistant) showed an earlier establishment and more rapid development of VAM fungi than up-to-date (highly susceptible). The first mycorrhizal infection in both SSC 1174 and Kufri Jyoti was observed after 12 days in 1980 and 8 days in 1981, whereas in up-to-date it was observed after 19 and 12 days respectively. The mycorrhizal infection increased with the age of the plants in all the three cultivars.     

植物基因转化技术在苹果遗传改良中的应用

近年来,苹果基因转化技术研究取得了较大进展,本文从转化体系,选择标记,报告基因及目的基因的遗传学行为等方面综述了苹果遗传转化研究发展现状,着重论述了其在苹果遗传改良中的应用,并对植物基因转化技术在莱果上的应用前景和应注意的几个问题进行了讨论。     

子莲杂交优势的利用及新品种选育的研究

1981—1987年的试验证实,利用杂交优势是子莲新品种选育的重要途径。作者通过杂交选育和引种,筛选培育出13号(白花建莲×红千叶)和2号(百叶莲×红花建莲)杂交子莲,杂交优势明显而稳定,其产鼠比对照品种——红花建莲增加20%以上,经济效益十分显著。为了推广这两种杂交子莲,作者还提出了子莲良种繁育时防杂的技术措施。     

Suppression of phenylalanine ammonia-lyase activity elicited in date palm by Fusarium oxysporum f. sp. albedinis hyphal wall elicitor

The inoculation of the seedling roots of the resistant (Bousthami Noir) and susceptible (Jihel) date palm (Phoenix dactylifera) cultivars by Fusarium oxysporum f. sp. albedinis induced an increase in phenylalanine ammonia-lyase (PAL) activity. The response of the PAL activity in the resistant cultivar was faster and higher than in the susceptible one. However, the elicitation of the seedlings with the hyphal wall elicitor (HWE) of the pathogen induced identical PAL activity in both cultivars. In the resistant cultivar, the the PAL activity elicited with the HWE was not influenced by the addition of the fungal culture filtrate (FCF) whereas it was suppressed in the susceptible cultivar. This FCF suppressor effect was dose-dependent, not influenced by sodium periodate, whereas it was strongly reduced by the heat (121 °C for 45 min) and pronase E. These results show that differential induction of the defence mechanisms in both cultivars was not related to differences in the induction of the PAL activity, but to the suppression of its elicitation in the susceptible cultivar.     

不同品种草莓果实挥发性物质的GC-MS分析

以草莓‘晶玉’、‘甜查理’、‘晶瑶’、‘章姬’和‘丰香’等5个品种为材料,采用顶空固相微萃取-气质联用技术,分析各品种果实挥发性物质成分差异,为草莓香味育种提供依据。结果表明,5个品种果实挥发性物质中酯类均占59%以上(59.36%～77.12%);丁酸乙酯、己酸乙酯、沉香醇、呋喃酮、丁酸甲酯、己酸甲酯、2-庚酮和橙花叔醇是5品种果实中主要的特征香味物质。     

Comparison of the life cycle of potato cyst nematode (<Emphasis Type="Italic">Globodera rostochiensis</Emphasis>) pathotype Ro1 on selected potato cultivars

The life cycle of Globodera rostochiensis pathotype Ro1 was studied under experimental conditions on selected potato cultivars (Korela, Albina, Vivaldi, Veronika, Vera, Monalisa, Victoria, Maranca, Désirée) in Slovakia during two growing seasons. Two peaks of second stage juveniles (J2) were found in the soil; the first peak three and four weeks after planting in the first and second year, respectively. The last J2 were found on 23 September. The number of J2 found in the second peak was much higher. First J2 associated with roots were observed 18 days, on middle early and seritonous cultivars 34 days after planting, but fourth stage juveniles (J4) were observed 40 days after planting in both cultivar groups. First adult males were found in soil 43 and 46 days after planting, respectively, and the last males two weeks later. White females filled with eggs were observed on roots 61 days after planting. The cycle from hatching of J2 in the soil to the hatching of J2 from brown cysts required 68 days in the first year and 60 days in the second year.     

中国六个城市大菊品种资源现状调查研究

对中国6个代表城市的大菊品种资源计2732份材料进行了调查、拍照及性状记录.通过比对分析,共整理出大菊品种1429个,现有品种可分为8个色系、5个瓣型和43个花型.其中黄色系居多,有500个品种,超过1/3,少见绿色、间色和双色品种.瓣型以平瓣为主,总计626个品种,占总数的44％,管瓣、匙瓣类次之,分别为414个和3...     

不同遮荫水平下4个玉簪品种的生长性状分析

研究了4 个玉簪品种(Hosta ‘Golden Edger’, H.‘Antioch’, H.sieboldiana ‘Elegans', H.plantagenea‘Aphrodite')在全日照的50%、30%和5%条件下的生长性状, 结果表明, 4 个玉簪品种的生长性状均受光照强度的影响, 随遮荫程度的加深, 所有供试品种的各生物量增量均表现下降, H.‘GoldenEdger'和H.plantagenea ‘Aphrodite'对光照较H.‘Antioch'和H.sieboldiana ‘Elegans'敏感, 前二者的适合生长光强为全光照的50%以上, 后两者适合生长的光强为全光照的30%~50%;光强对所有供试品种的单株总叶面积和株高均没有显著影响;各品种比叶重随光强减弱而下降;50%以上遮荫不利于芽及花序的产生。遮荫还改变各品种器官间的生物量分配比例, 50%以上遮荫使根生物量比例减少, 叶片生物量增加;随着遮荫程度的加深, 所有供试品种的各器官干重的总体减少程度大于鲜重。     

Nematodes associated with some date palm cultivars in relation to soil type

A survey was conducted during 2010 and 2011 to study the distribution of nematodes associated with certain date palm cultivars in Nubaryia and Giza in Egypt. The results revealed that the root knot nematode, Meloidogyne incognita was found at high population density and frequency of occurrence on the surveyed date palm cultivars in sandy loam soil in Nubaryia. The highest population density and frequency of occurrence of the root knot nematode were found on date palm cv. Al-Ekhlas followed by cvs. Barhi, Samani and Zaghlool. The spiral nematode, Helicotylenchus was found in soil of Samani and Zaghlool only. In clay loamy soil in Giza, Helicotylenchus spp. and Rotylenchulus renformis were found in association with certain date palm cultivars. As for Rotylenchulus reniformis, it was found at the highest population density and frequency of occurrence in the rhizosphere of Hayani followed by Zaghlool, Samani and Barhi. As for Helicotylenchus, it was found that the highest population density, also, was in the rhizosphere of Hayani followed by Samani, Barhi and Zaghlool in a descending order.