抗黑斑病兼抗青枯病花生品种的鉴定

鉴定了ＩＣＧ系统中２０个花生品种的黑斑病和青枯病的抗性,筛选出３个高抗黑斑病中抗青枯病的花生品种,１个中抗黑斑病高抗青枯病的品种。     

抗青枯病花生种质的遗传多样性

以栽培种花生2个亚种4个植物学类型的31份对青枯病具有不同抗性的种质为材料,通过SSR和AFLP技术分析了其DNA多样性,并与通过形态和种子品质性状揭示的表型多样性进行了比较。结果表明,不同类型的抗青枯病花生品种之间存在丰富的DNA多样性,SSR揭示的品种间遗传距离大于AFLP揭示的品种间遗传距离,基于二者的聚类分析结果趋势一致,结合花生的植物学类型、地理来源和系谱分析,以SSR的聚类结果与表型性状的聚类结果更为吻合。感病优质高产品种“中花5号”与密枝亚种的普通型和龙生型的抗病材料的差异很大,与育种中被广泛利用的抗源“协抗青”和“台山三粒肉”的差异相对较小,与“远杂9102”的差异更小。     

我国花生抗青枯病和黄曲霉病种质鉴定与利用研究进展

介绍了花生抗青枯病和黄曲霉病的遗传和抗性机制,重点综述了近年来我国抗青枯病和黄曲霉病种质的鉴定、品种的选育,以及相关分子标记和抗性基因等方面取得的研究进展及成就,旨在对相关研究工作的深入开展提供指导。     

野生花生抗青枯病种质的发掘及分子鉴定

以花生属5个区组的79份野生花生种质为材料,系统鉴定了野生花生对青枯病的抗性反应,从中发掘高抗青枯病的种质15份,含匍匐区组种质3份、直立区组1份、异形花区组1份、花生区组8份、未命名种质2份,抗病材料频率达到19%,高于栽培种花生资源的抗性频率。通过SSR分析表明,在所获得的抗青枯病野生花生材料中,四倍体野生种A.monticola与栽培种花生的亲缘关系最近,其次为花生区组的二倍体野生种A.duranensis和A.chacoense。根据DNA扩增结果,绘制了抗青枯病种质的指纹图谱,明确了其SSR分子特性。     

利用RIL群体创造抗黄曲霉兼抗青枯病的高油花生新种质

协同提高抗青枯病花生品种的黄曲霉抗性及含油量是我国花生育种的重要目标之一。利用远杂9102×中花5号杂交后代衍生的重组近交系群体(RIL),通过黄曲霉抗性、青枯病抗性鉴定及含油量测试,表明黄曲霉抗性受2对连锁并具累加作用主基因+加性多基因控制,含油量受2对具抑制作用主基因+加性多基因控制,RIL群体的黄曲霉抗性和含油量变异远远超过双亲的差异,表明它们均具有通过互补产生超亲性状的潜力。获得了抗黄曲霉或抗青枯病的高油后代家系18份,其中抗黄曲霉兼抗青枯病高油新种质1份(J091)。农艺性状和SSR分析结果表明,18份后代材料具丰富的遗传多样性,农艺性状优良,具有重要育种价值。     

烟草种质对青枯病抗性鉴定初报

对１５８ 份烟草种质资源青枯病抗性进行了４ 年的自然病地鉴定, 筛选出高抗材料４ 份, 仅占２５％ 。它们是 Ｒ Ｇ１７、 Ｏ Ｘ２０２８、 Ｒ Ｇ８ 和 Ｓ Ｐ Ｇ１１７。还有中抗４５ 份, 占２８５％ 。     

抗青枯病大花生新品种日花1号

花生青枯病是重要的花生细菌性病害,在很多国家和地区均有大面积发生．我国是世界上花生青枯病面积最大的国家．17个省、自治区病地面积在30万hm^2以上。长期以来．对花生青枯病未找到可行的化学药剂防治方法。实行轮作换茬虽能降低发病程度．但不能根除危害。种植抗病品种是当前国内外防治青枯病最重要的措施,既省工省力,又节约开支,还利于环保．经济效益、社会效益、生态效益明显。     

一种快速、有效鉴定花生青枯病抗性方法的建立

土传性青枯菌主要是从花生根部入侵,使花生植株出现感病表征。为建立一种室内快速、有效鉴定花生资源青枯病抗性的方法,通过设置不同的菌液浓度和接种时间长度,以伤根浸根法对2个抗感花生品种进行感病比较。试验结果表明,在该培养条件和接种方式下,进行抗性鉴定的最佳菌液浓度为3.0×107cfu/mL,浸根时间30 min。     

花生AFLP遗传图谱构建及青枯病抗性QTL分析

青枯病抗性分子标记能为花生抗青枯病育种提供辅助选择技术,以抗青枯病品种远杂9102与感病品种Chico杂交构建的重组自交系群体(RIL)为材料,用66对具多态性的引物(EcoR I/MseI引物组合35对,MluI/MseI引物组合14对,PstI/MseI引物组合17对)对其进行扩增,共检测到324个多态性位点。应用JoinMap(3.0软件对这些多态性位点进行遗传连锁分析,构建了一张栽培种花生的AFLP遗传连锁图。该图谱包含98个AFLP标记,涉及20个连锁群,覆盖总距离285 cM,标记间平均图距为2.90 cM。结合RIL群体的青枯病抗性鉴定结果,利用分析软件QTLNetwork(2.0共检测到与青枯病抗性相关的3个QTL(qBWr1、qBWr2和qBWr3)。其中,qBWr1和qBWr2均位于第4连锁群,qBWr3位于第14连锁群。这3个QTL形成2对具有加性×加性上位性互作效应的QTL区段(qBWr1/qBWr3和qBWr2/qBWr3),贡献率分别为12.81%和16.56%,共解释青枯病抗性总变异的21.62%。     

一种快速、有效鉴定花生青枯病抗性方法的建立

土传性青枯菌主要是从花生根部入侵使花生植株出现感病表征。为建立一种室内快速、有效鉴定花生资源青枯病抗性的方法,通过设置不同的菌液浓度和接种时间长度,以伤根浸根法对2个抗感花生品种进行感病比较。试验结果表明,在该培养条件和接种方式下,进行抗性鉴定的最佳菌液浓度为3.0×107cfu/ml,浸根时间30min。     

烟草种质资源及烤烟杂交组合对青枯病的抗性评价

在对85份烟草种质及46份烤烟F1组合进行的青枯病抗性鉴定中,未发现免疫或高抗材料,但不同材料对青枯病的抗性表现不同,感病材料发病早,病情指数上升速度快;抗病材料发病迟,病情指数上升速度慢.85份种质中筛选出了OX2028、RG17、K358等10份抗病种质及岩烟97、RG11、OX940等24份中抗青枯病种质.杂交组合的抗病性总体上优于烟草种质,以抗或中抗为主,但没有明显优势,其抗性多偏向于抗病性弱的亲本.     

Relationships among symptoms of spotted wilt disease of peanut and their potential impact on crop productivity and resistance breeding

Symptoms of spotted wilt of peanut were evaluated in a field experiment over three years (2010–2012) near Marianna, Florida. Assessment included three visual measures of disease and ImmunoStrip (a form of ELISA) testing of root crowns for the presence of Tomato spotted wilt virus (TSWV), the causal agent of spotted wilt in peanut. Foliar symptoms of spotted wilt on a 1 to 10 scale and on a disease incidence rating (DIR) were highly correlated (r = 0.88; p < 0.001). Foliar symptoms were moderately correlated (0.45 < r < 0.54; p < 0.001) with TSWV infection. However, symptoms on the testa were highly correlated with TSWV infection (r = 0.78; p < 0.001). These results indicate that foliar symptomology is less reliable in assessing TSWV infection than testa symptomology. Regression analysis showed that foliar symptoms underestimated the proportion of plants infected by TSWV. Seed inspection may be a good predictor of plant infection and therefore useful in breeding programmes because it is much less expensive than ELISA. Resistance to TSWV infection is characteristic of some resistant peanut genotypes and a lack of testa symptomology could help to identify those genotypes.     

Mapping of quantitative trait loci conferring resistance to bacterial wilt in tobacco (Nicotiana tabacum L.)

Tobacco bacterial wilt (TBW) is one of the most serious tobacco diseases in the world. Studies have shown that tobacco resistance to TBW is quantitatively inherited. This study aimed to map quantitative trait loci (QTL) conferring TBW resistance. An F_2 : 3 population containing 237 lines was developed from a cross between two flue‐cured tobacco cultivars, ‘Yanyan 97’ (YY97; moderately resistant to TBW) and ‘Honghua Dajinyuan’ (HD; highly susceptible to TBW), and a linkage map consisting of 201 simple sequence repeats (SSR) markers and spanning a total length of 2326.7 cM was constructed based on the population. Field experiments were conducted 2011 and 2012, and disease symptoms were investigated three times in each year. The phenotypic data were analysed either separately or jointly for QTL mapping using the software QTLNetwork 2.1. Eight QTL with significant main effects were mapped on chromosomes 2, 6, 12, 17 and 24. A major QTL (qBWR17a) was detected on chromosome 17, which explained up to 30% of the phenotypic variation. The results can facilitate marker‐assisted selection (MAS) in TBW resistance breeding programme.     

Heritability of spotted wilt resistance in a Florida‐EP™ “113”‐derived peanut (Arachis hypogaea) population

Spotted wilt, caused by tomato spotted wilt virus (TSWV), is a major disease of peanut (Arachis hypogaea ) in the south‐eastern United States. Cultivar resistance is the most important factor in disease control. However, spotted wilt resistance in current cultivars still carries risk in the absence of other practices when disease is severe. In contrast, a newly developed cultivar, Florida‐EP? “113,” has demonstrated excellent resistance even when spotted wilt is severe. Information on heritability of this resistance can help breeders better utilize it in breeding. F₂‐derived populations from the cross Florida‐EP? “113”/Georgia Valencia were developed and tested in field experiments in Florida from 2012 to 2014. Disease symptoms were evaluated visually, and the frequency of TSWV infection was measured by ImmunoStrip^®. Heritability estimated from ImmunoStrip^® was higher (0.66) compared to visual ratings (0.48). Genetic correlations among evaluation methods (r _A = 0.92–0.99) and environments (r _B = 0.86–0.99) were high. These results indicate that resistance in Florida‐EP? “113” is highly heritable and that selection in a high disease risk environment is feasible without significant erosion of genetic gain.     

Effectiveness of combining resistance to Thielaviopsis basicola and Tomato spotted wilt virus in haploid tobacco genotypes

Black root rot (BRR) caused by Thielaviopsis basicola as well as Tomato spotted wilt virus (TSWV) are the most serious problems in tobacco growing regions. We crossed the breeding line WGL 3 carrying BRR resistance derived from N.glauca with the line PW-834 the resistance of which to TSWV was transferred from cultivar Polalta. Anthers obtained from F₁ hybrid plants were cultured to induce haploids combining resistance to Th. basicola and TSWV. Flow cytometry analysis revealed 242 haploids and 2 spontaneous doubled haploids among regenerants. All haploids were cloned and then evaluated for BRR as well as TSWV resistance. The presence of pathogens was detected by microscopic evaluation of roots or using DAS-ELISA test. Microscopic assessment showed that, 132 haploids had no symptoms of Th. basicola which, together with the absence of symptoms in the F₁ hybrids, indicated a dominant monogenic mode of inheritance. At the same time only 30 haploids demonstrated resistance to TSWV. SCAR markers associated with TSWV resistance gene detection was applied. The results indicate that small proportion of TSWV-resistant haploids is probably due to the influence of deleterious genes flanking the resistance factor that reduced vitality of gametophytes. Altogether, 24 haploids showed multiple resistance to Th. basicola and TSWV.     

Pyramiding of Xa7 and Xa21 for the improvement of disease resistance to bacterial blight in hybrid rice

‘Minghui 63’ is a restorer line widely used in hybrid rice production in China for the last two decades. This line and its derived hybrids, including ‘Shanyou 63’, are susceptible to bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo). To improve the bacterial blight resistance of hybrid rice, two resistance genes Xa21 and Xa7, have been introgressed into ‘Minghui 63’ by marker‐assisted selection and conventional backcrossing, respectively. The single resistance gene‐introgressed lines, Minghui 63 (Xa21) and Minghui 63 (Xa7) had higher levels of resistance to bacterial blight than their derived hybrids, Shanyou 63 (Xa21) or Shanyou 63 (Xa7). Both Xa21 and Xa7 showed incomplete dominance in the heterozygous background of rice hybrids by infection with GX325 and KS‐1‐21. The improved restorer lines, with the homozygous genotypes, Xa21Xa21 or Xa7Xa7, were more resistant than their hybrids with the heterozygous genotypes Xa21xa21 or Xa7xa7. To further enhance the bacterial blight resistance of ‘Minghui 63’ and its hybrids, Xa21 and Xa7 were pyramided into the same background using molecular marker‐aided selection. The restorer lines developed with the resistance genes Xa21 and Xa7, and their derived hybrids were evaluated for resistance after inoculation with 10 isolates of pathogens from China, Japan and the Philippines, and showed a higher level of resistance to BB than the restorer lines and derived hybrids having only one of the resistance genes. The pyramided double resistance lines and their derived hybrids have the same high level of resistance to BB. These results clearly indicate that pyramiding of dominant genes is a useful approach for improving BB resistance in hybrid rice.     

Identification of QTL underlying the resistance of soybean to pod borer, <Emphasis Type="Italic">Leguminivora glycinivorella</Emphasis> (Mats.) obraztsov,and correlations with plant,pod and seed traits

Soybean (Glycine max L. Merr.) pod borer (Leguminivora glycinivorella (Mats.) Obraztsov) (SPB) results in severe loss in soybean yield and quality in certain regions of the world, especially in Northeastern China, Japan and Russia. The aim here was to evaluate the inheritance of pod borer resistance and to identify quantitative trait loci (QTL) underlying SPB resistance for the acceleration of the control of this pest. Used were the 129 recombinant inbred lines (RILs) of the F_5:6 derived population from ‘Dong Nong 1068’ × ‘Dong Nong 8004’ and 131 SSR markers. Correlations between the percentage of damaged seeds (PDS) by pod borer and plant, pod and seed traits that were potentially related to SPB resistance were analyzed. The results showed highly significant correlations between PDS by pod borer and plant height (PH), maturity date (MA), pod color (PC), pubescence density (PB), 100-seed weight (SW) and protein content existed. Soybeans with dwarf stem, light color of pod coat, small seeds, lower density of pubescence, early maturity and low content of protein seemed to have higher resistance to SPB. The correlated traits had potential to inhibit egg deposition and thereby to decrease the damage by SPB. Three QTL directly associated with the resistance to SPB judged by PDS at harvest were identified. qRspb-1 (Satt541–Satt253) and qRspb-2 (Satt253–Satt314) were both on linkage group (LG) H and qRspb-3 (Satt288–Satt199) on LG G. The three QTL explained 10.96, 9.73 and 11.59% of the phenotypic variation for PDS, respectively. In addition, 12 QTL that underlay 10 of 13 traits potentially related with SPB resistance were found. These QTL detected jointly provide potential for marker assisted selection to improve cultivar resistance to SPB. Guiyun Zhao, Jian Wang, and Yingpeng Han have equal contribution to the paper.     

Localization ability,latent period and wilting rate in eleven carnation cultivars with partial resistance to Fusarium wilt

Summary The latent periods, wilting rates and percentages of diseased plants were analyzed for 11 carnation cultivars after root and after stem inoculation with race 2 of Fusarium oxysporum f.sp. dianth. There was no conclusive evidence for the presence of an independent extravascular resistance mechanism, except for Lena plants in which, additional to the vascular resistance components, independent root-bound factors causing retardation of the colonization and wilting process were found. A large variation was observed in the ablity of the cultivars to localize the pathogen in the vascular tissue shortly after infection of the xylem. This ability was positively correlated with the latent period, and negatively with the wilting rate and final disease index. In resistant cultivars, secondary compartmentalization of the fungus higher up in the stem was also observed. After stem inoculation, differences among the cultivars in localization ability and wilt-retarding actors could be identified at an early stage by comparing the precentages of non-colonized plants or the percentages of plants lacking vascular discolouration.     

Effects of resistance genes,heat tolerance genes and cytoplasms on expression of resistance to Pseudomonas solanacearum (E.F. Smith) in potato

Summary Effects of resistance genes and heat tolerance genes on expression of resistance to bacterial wilt caused by Pseudomonas solanacearum were investigated in 30 F₁ progenies from parents with different levels of bacterial wilt resistance and heat tolerance. A race 1 and a race 3 isolate of the bacterium were used for inoculation under screenhouse conditions at two locations. Results obtained indicated that with reduction in levels of parental resistance, resistance in the F₁ progenies was also reduced. Under hot conditions, a reduced heat tolerance in the genetic background also resulted in lower levels of resistance expression. The effect of heat tolerance tended to diminish at lower temperatures leaving the effect of resistance genes more consistent. There existed a strong interaction between resistance genes and genes for heat tolerance. The nature of resistance to bacterial wilt in potato and implications for breeding for resistance are discussed.Effects of reciprocal crosses on expression of resistance to a race 1 isolate under hot screenhouse conditions, were studied in 5 sets of reciprocal F₁ progenies involving different resistant and susceptible parents. The reciprocal differences observed were not significant suggesting absence of cytoplasmic effects on expression of resistance.     

Induction of novel organelle DNA variation and transfer of resistance to frost and Verticillium wilt in Solanum tuberosum through somatic hybridization with 1EBN S. commersonii

Somatic hybridization can be used to induce genetic variability in plastidial and mitochondrial genomes, and transfer multiple uncloned genes across sexual barriers. Somatic hybrids were produced between a dihaploid clone of the common potato, S. tuberosum subsp. tuberosum, and the wild sexually incongruent diploid species S. commersonii. Fusion products were selected on the basis of callus growth and regeneration in vitro. Genome composition of putative somatic hybrids was determined by flow cytometric analysis of nuclear DNA content, RAPD analysis, and Southern analysis with probes specific to organellar DNA. All regenerated fusion products proved to be hybrids based on RAPD analysis. Seventy per cent of somatic hybrids were (near) tetraploids, 22% (near) hexaploids and 8%(near) octoploids. A high correlation was found between the nuclear DNA content determined by flow cytometry and the number of chloroplasts in stomata guard cell pairs. Somatic hybrids inherited the parental plastids in a random manner. On the contrary, they preferentially inherited the mitochondrial DNA fragments of S. tuberosum. The majority of them had a rearranged mitochondrial genome with fragments from both parents. Hybrids were highly vigorous and morphologically more similar to the cultivated than to the wild parent, produced tubers on long stolons under long photoperiod conditions, showed a high degree of flowering, but did not produce pollen. In addition, somatic hybrids were generally more resistant to frost and Verticillium wilt than the cultivated parent, indicating the introgression of relevant resistance genes from the wild species into the genetic background of S. tuberosum. This revised version was published online in July 2006 with corrections to the Cover Date.