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1.
Root‐knot nematodes, Meloidogyne spp., cause severe damage on solanaceous crops, including tomato and pepper. The objective of this study was to test whether nematodes virulent against the tomato Mi resistance gene were able to overcome the Me1 and Me3 resistance genes from pepper. For that purpose, a collection of 22 Meloidogyne arenaria, Meloidogyne incognita and Meloidogyne javanica isolates, avirulent or virulent against the Mi gene, was assembled. The reproduction of each isolate was evaluated on both susceptible and resistant tomato and pepper genotypes in a growth chamber. The Me1 resistance gene controlled all the avirulent and Mi‐virulent nematodes tested, and therefore appears promising for pepper breeding. In contrast, one M. arenaria and two M. incognita virulent isolates were shown to overcome the pepper Me3 resistance gene. These results encourage the testing of a large number of Meloidogyne isolates to evaluate the plant‐nematode interaction, which could have important consequences for the use and management of resistance genes in the field with respect to specificity and durability of the resistance.  相似文献   

2.
黑龙江省稻瘟病菌生理小种毒力基因分析与抗病育种策略   总被引：15，自引：1，他引：14  
近年来黑龙江省稻瘟病危害程度加重,给水稻生产造成巨大损失。为了解当地稻瘟病菌生理小种及其毒性基因的组成与分布,有针对性地利用抗性基因,选育抗病品种和使之合理布局,本文利用9个日本鉴别品种、7个中国鉴别品种、31个抗稻瘟病单基因系及12个当地主栽品种,对2006年采自该省主要积温区不同水稻品种的173个稻瘟病菌株进行致病性测定。结果鉴定出55个日本小种,优势小种为017、077、037、377和047,总频率为42.29%。鉴别力比较结果证实日本鉴别品种比中国鉴别品种更适合于当地稻瘟病菌致病性变异与小种分化研究。在12个主栽品种中,除龙粳14、龙盾104外,其他品种已经或正在丧失对稻瘟病的抗性。Pi9基因在所有积温区对稻瘟病菌株的抗谱都最广(平均94.80%),是当前黑龙江省水稻育种上极有价值的抗性基因;基因Piz-5(CA)、Piz-5(R)、Pita-2(R)、Pita-2(P)、Pi12(t)和Pi20(t)对供试菌株有高于70%的抗谱,也具有较高的利用价值。黑龙江省当前抗稻瘟病育种的策略应该是,在利用抗源龙粳14、龙盾104和Pi9的基础上,通过分子标记辅助选择方法聚合一至多个广谱抗性基因;同时加强对稻瘟病菌种群的监测和新抗源的发掘,有针对性地向主栽品种导入新的抗性基因。  相似文献   

3.
Potato progenies in a line x tester mating design and the clonal parents were screened for field resistance to potato leafroll virus (PLRV) to determine the heritability of this trait. Twelve advanced potato clones or varieties were crossed as pistillate parents to two pollen testers. The seedling progenies and clonal parents were exposed to aphid-transmitted potato leafroll virus for two growing seasons. Cumulative infection by potato leafroll virus was determined by post-season sero-logical indexing of foliage grown from sprouted tubers after 2 years of exposure. Narrow-sense heritability was estimated from regression of mid-parent on progeny as h = 0.72. This estimate indicates a high level of useabie genetic variance for PLRV resistance in advanced breeding materials. Although variation in resistance to PLRV appears to be a quantitative trait in susceptible and moderately resistant clones, per-formance of the most resistant parents suggests that genes with major effects may be present. These results are similar to the conclusions of other researchers who found one or two genes controlling the pheno-types of extreme resistance, resistance to infection, or suppression of virus titre.  相似文献   

4.
Summary Seven wild diploid potato species, Series Tuberosa, representing 1023 clones were screened for resistance to the potato cyst nematode, Globodera pallida. Over 25% of the clones were resistant to pathotype P4A and almost 30% were resistant to pathotype P5A. The resistance in hybrid progenies of these and other resistant species with cultivated potatoes was evaluated, and over 2200 seedlings were screened. High frequencies of resistance (>50%) to P4A were found in progenies with Solanum leptophyes, S. vernei, S. gourlayi and S. capsicibaccatum, whereas resistance to P5A was found in these species as well as S. sparsipilum. The importance of nematode resistant wild species for potato breeding is discussed.  相似文献   

5.
Potato cyst nematodes (PCN) collected in six localities in the Leningrad region of North West Russia were identified as Globodera rostochiensis pathotype Ro1 and were used for subsequent resistance tests. Seventy‐nine accessions of cultivated and closely related wild potato species from the VIR collection in Russia were screened on resistance to G. rostochiensis pathotype Ro1 and on the presence of molecular markers for H1 and Gro1‐4 resistance genes. No associations were detected between the resistance level of diploid and tetraploid Andean and tetraploid Chilean potato landraces (indigenous cultivars) and their related wild species and their geographical distribution or presence of PCR‐based markers that are associated with the H1 and Gro1‐4 genes. At the same time, all susceptible genotypes lacked such markers. New sources of resistance were found and could be used in breeding.  相似文献   

6.
Genetic basis of seedling-resistance to leaf rust in bread wheat 'Thatcher'   总被引：1，自引：0，他引：1  
A. N. Mishra    K. Kaushal    G. S. Shirsekar    S. R. Yadav    R. N. Brahma    H. N. Pandey 《Plant Breeding》2005,124(5):514-516
The bread wheat cultivar ‘Thatcher’ is documented to carry the gene Lr22b for adult‐plant resistance to leaf rust. Seedling‐resistance to leaf rust caused by Puccinia triticina in the bread wheat cultivar ‘Thatcher’, the background parent of the near‐isogenic lines for leaf rust resistance genes in wheat, is rare and no published information could be found on its genetic basis. The F2 and F3 analysis of the cross ‘Agra Local’ (susceptible) × ‘Thatcher’ showed that an apparently incompletely dominant gene conditioned seedling‐resistance in ‘Thatcher’ to the three ‘Thatcher’‐avirulent Indian leaf rust pathotypes – 0R8, 0R8‐1 and 0R9. Test of allelism revealed that this gene (temporarily designated LrKr1) was derived from ‘Kanred’, one of the parents of ‘Thatcher’. Absence of any susceptible F2 segregants in a ‘Thatcher’ × ‘Marquis’ cross confirmed that an additional gene (temporarily designated LrMq1) derived from ‘Marquis’, another parent of ‘Thatcher’, was effective against pathotype 0R9 alone. These two genes as well as a second gene in ‘Kanred’ (temporarily designated LrKr2), which was effective against all the three pathotypes, but has not been inherited by ‘Thatcher’, seem to be novel, undocumented leaf rust resistance genes.  相似文献   

7.
山东省和河北省小麦白粉菌毒性与遗传多样性分析   总被引：2，自引：0，他引：2  
由Blumeria graminis f. sp. tritici引起的白粉病是危害我国小麦安全生产的重要病害之一。分析菌株毒性结构和抗病基因有效性对于利用寄主控制白粉病具有重要意义。本研究对2011年从山东和河北两省分离的41个菌株进行了毒性分析,并采用SSR标记对其遗传多样性进行了分析。测试菌株的毒性频率在0.35 (Bg40-2,山东烟台)至0.74 (Bg46-1,山东平度)之间。山东省菌株的平均毒性频率与河北省菌株没有显著差异。除别菌株外(例如Pm17),山东省和河北省的菌株对大多数抗病基因的毒性差异不大。全部测试菌株对来自地方品种齿牙糙的Pm24基因都没有毒性。极少数菌株对Pm1c、Pm16、Pm20、PmH和Mlxbd的毒性频率低于0.1,在河北省邯郸市和黄骅市发现对Pm21基因具有毒性的菌株,但在山东省没有检测到对Pm21具有毒性的菌株。对Pm5e、 Pm6、 Pm12、 Pm13、 Pm17、 Pm40、 Pm2+6和Pm5+6的毒性频率在0.18~0.48之间,对Pm1a、 Pm3a、 Pm3c、P m3g、 Pm4a、 Pm4b、 Pm5a、 Pm7、 Pm8、 Pm19、 Pm33、 Pm43、 PmY39、 PmPS5A和Pm1+2+9的毒性频率超过0.6。遗传多样性分析可见,小麦白粉菌群体的遗传变异主要发生在群体内部,菌株间具有一定程度的基因交流。同一地点采集的不同单孢分离菌株有些可聚为一类,但有些不能聚为一类,说明其遗传基础可能存在差异。供试菌株对不同抗病基因的毒性多态性与DNA多态性之间不存在一一对应的关系。  相似文献   

8.
番茄叶霉菌无毒基因的研究进展   总被引：1，自引：0，他引：1  
无毒基因是病原物遗传因子,其编码的产物激发病原物与植物特异性相互作用。病原物无毒基因与植物抗病基因产物间直接或间接相互作用导致产生的基因对基因抗性是植物抗病性的重要形式。番茄与叶霉病之间的特异互作被认为是遵循Flor的“基因对基因”假说的典型体系。绝大多数已克隆的无毒基因之间,及其与已知蛋白之间,均无显著的序列同源性。无毒基因具有双重功能：在含瓦补抗性基因植物中表现无毒效应,而在不含互补抗性基因植物中显示毒性效应。本文综述了番茄叶霉菌无毒基因的多样性、意义、结构及其功能等等,了解病原菌无毒基因的结构及功能,有助于了解病原物与植物的识别机制,对认识植物的抗病性,特别是非寄主植物对病原菌的广谱抗病性也具有重要意义。  相似文献   

9.
A set of 21 monosomic (2n ‐ 1) and the disomic (2n) lines of the ‘Chinese Spring’ cultivar were crossed with ‘Chirya‐3′, the CIMMYT synthetic wheat line which has been identified as highly resistant for Helminthosporium leaf blight disease (HLB), in order to locate the genes governing disease resistance. The F1 and segregating populations were challenged and screened against the most virulent pure mono‐conidial HLB isolate KL‐8 (Karnal, India). The F1 progenies of the crosses were found to be susceptible because of the recessive nature of resistance. The F2 progeny of the control cross (‘Chinese Spring’בChirya‐3’), segregated in the ratio of 1: 15 (resistant: susceptible), indicating that resistance to HLB was controlled by a pair of recessive genes. While the F2 progeny of 19 monosomic crosses segregated in the ratio of 1: 15 (resistant: susceptible), the progeny of the remaining two crosses, 7B and 7D, deviated significantly from the ratio, revealing that 7B and 7D were the critical chromosomes for resistance genes that were located one on each chromosome. Moreover, the critical lines, 7B and 7D, confirmed the digenic complementary recessive nature of gene action by fitting well with the overall pooled F2 segregation ratio of 13: 51 (resistant: susceptible) as expected for digenic complementary recessive resistance. The F3 segregation ratios of the critical crosses, based on their pooled F2 analysis, was estimated as 19: 32: 13 (non‐segregating susceptible: segregating as susceptible and resistant: non‐segregating resistant). F3 progenies when tested with these ratios showed goodness‐of‐fit, confirming that the two pairs of recessive resistance genes were located on chromosomes 7B and 7D.  相似文献   

10.
A synthetic winter rye population was produced with two race-specific powdery mildew resistance genes, one dominant (Rm1) and the other (rm2) recessive, each at a frequency of about 0.50. The population was advanced by open-pollination in an isolated plot under mildew-free conditions for eight years. Samples of generations Syn-0 through Syn-7 were inoculated in the laboratory with two mildew isolates, one avirulent to either resistance gene, the other virulent to Rm1 and avirulent to rm2, to discriminate resistant and susceptible phenotypes. From the proportions of resistant plants, frequencies of Rm1 and rm2 were calculated and the fitness of carriers of resistance alleles was estimated in relation to carriers of susceptibility alleles at the two loci using continuous models and linear regression analyses. Frequencies of the two resistance genes oscillated only weakly over the eight generations. Coefficients of selection against Rm1-and rm2rm2 genotypes were –0.04 and –0.02, respectively, and not significantly different from zero. Thus the two resistance genes were selectively neutral. It is concluded that pyramiding of major powdery mildew resistance genes in rye varieties should not reduce their yield potential in the absence of mildew.  相似文献   

11.
X. Wang    Y. Jacob    S. Mastrantuono    J. Bazzano    R. Voisin  D. Esmenjaud 《Plant Breeding》2004,123(1):79-83
The spectrum and inheritance of resistance to the root‐knot nematode Meloidogyne hapla was studied in the diploid species Rosa multiflora and R. indica. The host suitability of seven rose rootstocks, namely five R. multiflora (K2, K1, Floradale, CE63 and CE65) and two R. indica (CE35 and Maroc) clonal accessions, was evaluated using four geographic isolates of M. hapla. Plants grown under greenhouse conditions were tested at high and durable inoculum pressure of nematodes and rated for nematode infestation five months after inoculation on a 0–5 gall index. Different host suitabilities to M. hapla were demonstrated depending on the nematode isolates: in R. multiflora, the clone K2 had a resistant (R) response to all isolates; the clone K1 ranged from intermediate (I) (isolate ‘Canada’) to resistant (other isolates), Floradale was shown to be intermediate, whereas CE63 and CE65 were moderate to good hosts (H). In R. indica, both rootstocks were good to excellent hosts for the isolate Canada but resistant to all three other isolates, thus expressing an isolate‐specific resistance. A study on the genetics of resistance in R. multiflora to the M. hapla isolate Canada was then conducted using an incomplete diallel cross involving all previous clones except Floradale. A total of 120 hybrid individuals belonging to several progenies representing the cross combinations R × I, R × H, I × H and H × H were evaluated. Individuals of each progeny generally ranged into a monomodal distribution that suggests polygenic inheritance of resistance. In the family Rosaceae, the differences in the resistance genetics to the meiotic species M. hapla and to the mitotic species, M. arenaria, M. incognita and M. javanica are discussed in relation to the reproductive status of the nematodes.  相似文献   

12.
Genetic studies were undertaken to determine the number and identities of leaf rust resistance genes in common wheat lines Agra Local and IWP94. The infection type arrays of the two lines with eight pathotypes (pt.) of P. triticina were different from those of lines possessing known leaf rust resistance (Lr) genes. Agra Local possessed two recessive resistance genes, one conditioning resistance to pathotype 4R9-7, and the other, a temperature-sensitive factor, gave resistance to pt. 121R127 at high temperature (27°C). IWP94 was previously demonstrated to carry Lr23. From the present study IWP94 was determined to have at least four leaf rust resistance genes. The first of these was the same recessive gene conferring resistance to pathotype 4R9-7 which was found in Agra Local. A second partially dominant gene conferred resistance to pathotype 121R127 at high temperature and two additional recessive genes governed resistance to pathotype 93R15. When present together, these two recessive genes complemented each other and provided resistance to pathotype 69R13 as well. One of the two recessive genes conferring resistance to pathotypes 93R15 and 69R13 was Lr23.  相似文献   

13.
Genetic basis of adult plant leaf rust resistance in three released Indian wheat cultivars viz. DWR195, RAJ3765 and HP1731 was investigated through detailed inheritance study under controlled polythene house condition at Flowerdale, India. The F2, F3, F4 and F5 generations were analyzed with the most frequent and virulent Indian leaf rust pathotype 121R63-1. Two complementary recessive genes imparted resistance in DWR195, two complementary dominant genes governed the resistance of RAJ3765 whereas two independent dominant genes were involved in the resistance of HP1731. The genes responsible for adult plant resistance in the three cultivars were not allelic. The two complementary genes of DWR195 and two independent dominant genes of HP1731 have been isolated as single gene lines. Utilization of resistance from HP1731, which carries two independent dominant genes, will be easy as compared to DWR195 and RAJ3765.  相似文献   

14.
The R10 late blight differential of potato, 3681ad1, exhibits good field resistance. Progeny from the cross between 3681ad1 and the susceptible cultivar ‘Katahdin’ were assessed for late blight resistance to three Phytophthora infestans isolates, using a detached leaf assay. Progeny differed in response to the three isolates. Resistance to isolates IPO‐0 and 99018 was controlled by quantitative trait loci (QTL), whereas resistance to isolate 89148‐9 was inherited as a dominant R gene, designated as R10 in this study. Statistical analysis revealed that one of the resistance QTLs to isolates IPO‐0 and 99018 is linked to the R10 gene, which maps to chromosome 11 in a region where a complex late blight resistance locus has been reported previously. A high‐resolution map of R10 was constructed using a large segregating population, and the gene was delimited to a genetic interval of 0.26 cM. The clustering of the qualitative gene R10 with resistance QTLs could explain the field resistance observed with 3681ad1.  相似文献   

15.
由致病疫霉菌(Phytophthora infestans)引起的晩疫病是世界范围内最具毁灭性的马铃薯(Solanum tuberosum)病害。以含有晚疫病抗性基因R11的材料MaR11和不含已知抗性基因的品种Katahdin为亲本进行有性杂交,对获得的F1分离群体的83个基因型进行了晚疫病菌株接种鉴定和遗传分析。结果表明,R11为主效单基因,在MaR11中以单式形式(R11r11r11r11)存在。应用比较作图和分离群体分组分析(BSA),开发了6个与R11连锁的分子标记,并将R11定位于11号染色体长臂末端。R11距C2_At5g59960标记最近,约为2.4 cM。通过遗传图谱比较表明,R11较晚疫病抗性基因R3a和R10更靠近染色体端粒区。本研究所获得的遗传图谱为进一步构建R11高密度遗传图谱提供了基础。  相似文献   

16.
Summary The presence of resistance to potato cyst-eelworm in wild Lycopersicon species was confirmed.The resistance of two plant accessions, L. pimpinellifolium, B6173, and L. peruvianum, B6001, was compared in screening tests against three eelworm isolates, using the susceptible L. esculentum Ailsa Craig as a control. Both accessions were shown to possess high levels of resistance to the Wren isolate (pathotype A) of H. rostochiensis, and resistance to the Castle Donington (pathotypes A, B, and E) and Hare Lane (pathotype B) isolates. The level of resistance in L. pimpinellifolium was greater than that in L. peruvianum. Because of its greater resistance, and the ease with which it can be hybridised with tomato cultivars, L. pimpinellifolium was chosen as a donor parent for breeding programmes designed to incorporate potato cyst-eelworm resistance into a commercial tomato variety.The resistance of L. pimpinellifolium, B6173, to the Wren isolate of H. rostochiensis was shown to be controlled by a single dominant gene for which the symbol Hero is proposed.  相似文献   

17.
The Rysto gene from Solanum stoloniferum introduced into potato cultivars (Solanum tuberosum L. ssp. tuberosum) confers resistance to potato virus A, potato virus V and potato virus Y (PVY). In addition to PVY, tobacco etch virus (TEV) and a TEV construct that encodes β‐glucuronidase (TEV‐GUS) were inoculated to determine the inheritance of resistance to these viruses in progenies obtained from potato cultivars containing the Rysto gene. While cultivars ‘Karlena’ and ‘Delikat’ were susceptible, ‘Bettina’ and clone 927eY were resistant to PVY, TEV and TEV‐GUS, as determined by enzyme linked immunosorbent assay, biotest and GUS assay, respectively. The segregation ratios obtained from the progenies of ‘Bettina’בDelikat’ and 816eY בKarlena’ indicate that resistances to PVY and TEV are governed by one dominant gene or two genes tightly linked in coupling phase. Evidently, Rysto confers broad spectrum resistance to potyviruses. TEV resistance could be reliably detected 4 days after inoculation with the TEV‐GUS construct by GUS assay. Therefore, the GUS‐tagged TEV construct can be used for early selection for resistances based on the gene Rysto or closely linked genes.  相似文献   

18.
The virulence spectra of 50 Rhynchosporium secalis isolates from a population in the Western Cape province of South Africa were determined, and 21 races were detected when evaluated against 17 differential cultivars. The virulence spectrum of the R. secalis population shows considerable variation, and carries unnecessary virulence genes which is quite unexpected, since chiefly susceptible barley cultivars are grown in the south Western Cape. The two most prevalent races, namely races 4 and 7 had three and four virulence genes respectively. Both race 4 and 7 were virulent on the most susceptible cultivars, West China, Steudelli, C.I.8618 and C.I.2226. Considering the resistance genes reported for the cultivars Atlas 46, Turk, and C.I.3515 which showed no susceptible cultivar-pathogen interaction, it would appear that the Rh-Rh3-Rh4 complex is primarily involved in conferring resistance to the local R. secalis isolates This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
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.  相似文献   

20.
陆地棉品种对多个大丽轮枝菌菌株的抗性分析   总被引：1，自引：1，他引：1  
对几个陆地棉黄萎病抗源用多个菌株分别接种鉴定。结果表明，它们对不同菌株的抗性可能是由不同基因决定的。例如Ｒ０１中有多个抗不同大丽轮枝菌菌株的抗病基因；Ｒ１８能抗４个落叶型菌株，且表现一致，这说明Ｒ１８的抗病基因与Ｒ０１的抗病基因在本质上可能不同。Ｒ０１和Ｒ０３中的２个株行能抗或耐所有试验用菌株尤其是落叶型菌系。Ｒ１８的选择过程为选育棉花高抗黄萎病品种提供了可能参考的实例。抗源材料的分析结果表明，一个品种或株行的抗性鉴定必须进行两次以上，在感病株行中分离出来的抗病单株，是新品种、新材料的希望所在，也是不能遗传的假抗病材料（诱导性抗病）的最大怀疑对象。  相似文献   

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