Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya

Sweet potato virus disease (SPVD), a result of the co-infection of whitefly transmitted Sweet potato chlorotic stunt virus (genus Crinivirus, family Closteroviridae) and the aphid transmitted Sweet potato feathery mottle virus (genus Potyvirus, family Potyviridae), is the most destructive disease of sweet potato in East Africa. A study was conducted to establish if genotypes identified as resistant or susceptible to SPVD in Kenya could be distinguished using molecular markers. A total of 47 unrelated sweet potato genotypes were selected from germplasm collections and classified into two phenotypic groups as resistant or susceptible to SPVD. Genotype selection was based on disease severity or days to symptom development in plants following graft inoculation. Amplified fragment length polymorphism (AFLP) marker profiles were generated for each individual and used in association studies to identify markers suitable for classifying the two pre-defined phenotypic groups. Analysis of molecular variance showed significant (P < 0.002) variation between the two groups using 206 polymorphic AFLP markers. Discriminant analysis and logistic regression statistical methods were used to select informative markers, and to develop models that would classify the two phenotypic groups. A training set of 30 genotypes consisting of 15 resistant and 15 susceptible were used to develop classification models. The remaining 17 genotypes were used as a test set. Four markers, which gave 100% correct classification of the training set and 94% correct classification of the test set, were selected by both statistical methods.     

甘薯与小麦套作对甘薯农艺性状及产量的影响

以10个不同类型的甘薯品种为试验材料,采用随机区组设计,以纯作为对照,研究小麦与甘薯行数比在3∶1和2∶1套作模式下甘薯地上部农艺性状和2种作物鲜产的变化。结果表明:参试甘薯最长蔓长比纯作减小;分枝数和茎粗因品种差异变化不尽一致;漯薯14号在3∶1模式种植时较纯作增产18.77%,漯薯15号在2∶1套作模式下较纯作增产3.99%,其余甘薯品种及小麦鲜产均不同程度下降;套作兼用型(漯薯11号和漯薯15号)甘薯品种产量更高;麦薯3∶1比2∶1套作模式更具优势。     

Screening sweet potato for source potentials

Summary Screening sweet potato, Ipomoea batatas, L., for source potentials is more difficult than for sink capacities. Twenty clones were grafted to four tester varieties to screen them for source potentials in relation to sink capacities which are interdependent. Source potential of a clone was measured by its average scion effect when grafted on the four tester varieties. There were significant differences in source potentials among the twenty clones. Seven clones were selected for having high source potentials. Clone TIS 2498 was the best. Degrees of response of source to sink were estimated using the regression method for twenty clones showed significant differences and ranged from b–0.45 to b=2.06. Source potential showed significant relationship (r=0.62^**) with response of source to sink. Implication of this approach to sweet potato breeding is discussed.     

甘薯缺锌及防治措施

通过对甘薯缺锌原因、症状、测试诊断及防治措施的分析研究，为甘薯高产提供技术支撑。１缺锌原因作物的矿物养分供给不仅取决于土壤中这种养分的总含量，而且也取决于在任何时候都以有效形式存在的养分总量的比例。一般酸性土壤含锌量较低，而碱性土壤因其锌元素溶解度降低，有效锌也低。而且全部养分中通常只有一小部分可被吸收，所以均会出现缺锌现象。由于提高土壤pH值能降低其锌元素的可溶性，因此，对含锌量低的酸性土壤施石灰便会导致缺锌。另外施用含铜元素肥料或是大量施磷肥，也可以加剧缺锌。２缺锌症状甘薯缺锌的主要症状是其…     

甘薯施肥技术

甘薯适应性广,抗逆性强,是高产稳产粮食作物之一.要获得甘薯高产,就必须适时施足肥料,满足甘薯各生育阶段正常生长对养分的需求.现就甘薯需肥规律及施肥技术介绍如下,供参考.     

中国甘薯品种30年

对我国30年来审(认、鉴)定的160个甘薯品种进行分类研究,指出了品种编号的更替和意义,表明近10年选育的甘薯品种干物率平均提高了近2个百分点;食用型品种仍然占据着甘薯品种的重要地位;亲本使用频率前3位的品种是徐薯18、金山57和徐781,可作为育种的核心亲本;适宜三大区域甘薯品种类型和数量基本上适合当前我国甘薯消费水平的需求。该研究对甘薯育种工作者有很好的参考作用。     

甘薯脱毒技术的研究与应用

本文论述了甘薯病毒病的发现及危害,阐明了甘薯脱毒的生物学原理,探讨了甘薯茎尖组织培养、病毒检测及脱毒试管苗的快繁技术,分析了脱毒甘薯四级生产程序及增产性能,提出了脱毒甘薯存在的问题与应用前景.     

甘薯综合加工研究

本文在介绍甘薯营养保健功能基础上,简述了甘薯的综合加工技术,并对未来的研究开发重点进行了展望。     

Breeding research in sweet potato,Ipomoea batatas poir

In the sweet potato fruit formation following artificial selfing, artifical cross pollination and natural pollination was investigated. Artificial self-pollination in one case gave a fruit formation of 21.2%; in five other cases no or hardly any fruit formation took place. Artificial cross-pollination produced a fruit formation varying from 0 to 52.9%. Natural fertilization did not occur in cases when the nearest flowering sweet potato clone stood at a distance of 80 m. When other flowering clones were in the direct vicinity the percentage of fruit formation through natural pollination differed from 0 to 25.2%.Pre-treatment of sweet potato seed with concentrated sulphuric acid applied during 10 or 20 minutes had a favourable effect on the speed of germination and the germination percentage, also when the seed after treatment was kept in store in or outside an exsiccator for one or two months. The method of scarifying the seed showed a reasonably good influence in this respect. Two different warm water treatments were not or practically not satisfactory.     

Breeding research in sweet potato,Ipomoea batatas Poir

As the sweet potato, Ipomoea batatas Poir, is propagated vegetatively its selection is comparatively simple. Choice of parents and selection procedures were carried out on the basis of yield capacity, resistance or tolerance to a fungus and virus disease, resistance to Cylas formicarius F. and the shape and size of tubers. Because insufficient data were available the protein content played no important role in the choice of parents. In the selection procedures, also this character could not yet be taken into account because the laboratory equipment was insufficient. This might have changed in the future.In the selection fields the new clones were planted by the side of a well-known test-clone, in such a way, that every new clone had a test on either side. At every selection cycle 25% of the new clones was kept for further research while the rest was rejected. On two generations the visible disease symptoms of new clones increased considerably while their production capacity decreased. For various characters a clear relation could be demonstrated between the phenotype of the parents and their offspring.     

Sterility in some species related to the sweet potato

Summary The kinds and sites of sterility and inviability were noted in induced tetraploids of threeIpomoea species, and of hybrids ofIpomoea lacunosa withI. trichocarpa. Tetraploids were somewhat less fertile than diploids, but seeds were normal appearing and ususally viable. Hybrids were much less fertile. Hybrid sterility occurred as pollen abortion, pollen germination failure, and in failure of pollen tube growth. Small and underdeveloped seeds failed to germinate. The sterility of hybrids (but not of tetraploids) is thus very similar to that of the hexaploid sweet potato. Sterility suggests developmental inbalance, which is probably due to genic and perhaps minor chromosomal differences among the parent species of the sweet potato. Hybrid sterility of the sweet potato may have been fixed by polyploidy, and thus may be impossible to eliminate.     

脱毒甘薯工厂化四级程序繁育技术

脱毒甘薯工厂化四级程序繁育技术是指利用茎尖分生组织,在无病毒条件下大量培养培育脱毒种苗,从茎尖组织培养到大田种苗按繁育种苗世代高低和质量标准等分成四级,即高级脱毒苗(育种家种子)、脱毒原原种苗(原原种)、脱毒原种苗(原种)、脱毒良种苗(良种),而脱毒良种苗应用于生产的主要形式是统一供种.其关键技术如下.     

甘薯新品种龙薯9号选育研究

根据甘薯产业化发展需要,采用最新育成品种间(岩薯5号/金山57)进行杂交,选育而成甘薯新品种龙薯9号,该品种具有早熟、高产、抗病、适应性广等特点;不但鲜薯、薯干产量均比对照金山57显著增产,而且可利用其早熟、高产的特点,实现甘薯生产的周年供应和抗灾救荒用种均有现实意义。     

Regression analysis of genotype x environment interaction in sweet potato

Summary Two experiments, each involving a set of 10 sweet potato clones, were conducted for three years at 4 sites (Ekona, Ebolowa, Nkolbisson, and Bambui Plain) in Cameroon. Data obtained were subjected to analysis of variance to determine the presence of genotype x environment (G x E) interactions, and to regression analysis to assess the performance of clones across anvironments. Environments were assessed in two ways: (i) the mean response of all clones (dependent assessment), and (ii) the average performance of a different set of clones (independent assessment).The first experiment (Expt 1) produced higher yields but had fewer stable clones than the second (Expt 2).The analysis of variance revealed that the clones interacted significantly with environments for all traits.The study has identified high yielding and stable sweet potato clones for distribution to growers in the major areas of cultivation in the tountry. Despite slight differences in numbers of clones judged stable by the various regression indices in the two methods of environmental assessments, the rankings of clones on the basis of their linear regression coefficients were similar. In a developing country like Cameroon, with limited resources and where sophisticated equipment for obtaining physical or biological measures of the environment may be lacking, the mean performance of genotypes may still be the most reliable measure of environment in evaluating the stability of performance of crop cultivars.     

临沂市甘薯产业发展研究与对策

通过调查甘薯种植大户、家庭农场、农民专业合作社及加工企业等,对临沂市甘薯产业发展现状、存在的问题进行分析。提出了增加甘薯产业资金投入来打造甘薯特色小镇,强化甘薯品牌打造,运用线上线下运营模式助推甘薯销售,引进新品种,推广绿色防控技术等建议,进一步推动甘薯产业提质增效。     

甘薯茎线虫病的发生与防治

甘薯茎线虫病又名糠心病、空心病、油梆子.此病1937年传入我国,随着农民之间的引种和调种,病害在河南省大面积发生与流行,并成为河南省甘薯产区的主要病害之一,尤以洛阳、禹州、郸城、鹤壁等地区发生较为严重.     

脱毒甘薯人工种子研究

人工种子技术是近年来在植物细胞培养和组织培养基础上产生的一门新技术,它在快速繁殖无性系、基因工程等方面有着广阔的应用前景.从人工种子技术诞生以来,已在芹菜、苜蓿、胡萝卜、雍菜和一些林木植物上有人工种子研制的报道.甘薯的脱毒和组培快繁技术是当今农业上应用比较成熟的生物技术,而关于脱毒甘薯人工种子的研究尚未见报道,研制脱毒甘薯人工种子对提高甘薯脱毒苗的繁殖倍数、促进脱毒甘薯的推广有重要的意义.为此我们进行了脱毒甘薯人工种子的制作研究.     

甘蔗脱毒种苗组织培养技术研究

甘蔗是无性繁殖作物，生产上主要用蔗茎作种，由于多年种植后受到各种病源物的侵染，造成原有优良品种的产量和品质下降。在生产上，危害甘蔗的主要病害有凤梨病、眼点病、黑穗病、花叶病、宿根矮化病等。其中花叶病和宿根矮化病用一般的化学药剂难以防治，花叶病一般使甘蔗减产１０％～４０％，宿根矮化病可使甘蔗减产１０％～３０％，干旱时感病率可达１００％。因此，采用甘蔗脱毒培养技术，生产健康种苗，是恢复甘蔗优良品种种性、提高甘蔗生产的有效手段。关于甘蔗种苗的脱毒培养，巴西、古巴等国早在２０世纪７０年代末便进行了研究，…     

甘薯基因组NBS-LRR类抗病家族基因挖掘与分析

NBS-LRR类基因家族是植物抗病R基因(Resistance gene)数量最多的一类,具有NBS (Nucleotide-binding site)和LRR (Leucine-leucine-repeat)结构域。甘薯(Ipomoea batatas)栽培种基因组已完成测序,但尚未注释,本研究对甘薯基因组序列进行外显子预测,得到甘薯染色体组全基因组蛋白序列,在此基础上进一步对NBS-LRR家族基因鉴定和分析表明,甘薯基因组中含有379个NBS-LRR家族基因,占全基因组基因总数的0.212%,其中N型亚家族120个,NL型103个, CNL型133个, TNL型22个, PN型1个。所有染色体上均有NBS-LRR家族基因分布,但数量明显不同,其中有60.9%的NBS-LRR基因序列呈簇状分布。NBS-LRR基因序列有15个保守结构域,在N端较为保守。研究结果为甘薯进一步开展NBS-LRR家族基因的功能研究和抗性育种提供了参考。     

Variation in sweet potato for tolerance to some physical and biological stresses

Summary Sweet potato cultivars, breeding lines and unselected seedling clones were grown under 9 stress conditions in field and greenhouse; heavy soil, space competition, competition with maize, shading, flooding, drought, acidity, salinity, and weevil infestation. High root yield was considered to be a sign of stress tolerance. Stresses were shown to reduce the growth of shoots and roots, except flooding, which increased fibrous root production. The percentge of plants showing high stress tolerance varied from 0.35 to 30.90 for the different stress situations. Tolerances to stresses tended to occur together, as shown by low but significant correlations, significant chi-squares for numbers of plants with multiple stresses, and by low but significant correlations between yield and multiple stresses. Root flooding, space and fertility competition, and soil acidity appear to be the stress factors most closely related to production in heavy soils. Yet the magnitude of the correlations suggest that other factors or random variation also affect yield, and thus the predictive value of greenhouse stress test is presently limited.