共查询到20条相似文献,搜索用时 31 毫秒
1.
Frederick J. Muehlbauer Seungho Cho Ashutosh Sarker Kevin E. McPhee Clarice J. Coyne P. N. Rajesh Rebecca Ford 《Euphytica》2006,147(1-2):149-165
Summary Lentil is a self-pollinating diploid (2n = 14 chromosomes) annual cool season legume crop that is produced throughout the world and is highly valued as a high protein
food. Several abiotic stresses are important to lentil yields world wide and include drought, heat, salt susceptibility and
iron deficiency. The biotic stresses are numerous and include: susceptibility to Ascochyta blight, caused by Ascochyta lentis; Anthracnose, caused by
Colletotrichum truncatum; Fusarium wilt, caused by
Fusarium oxysporum; Sclerotinia white mold, caused by
Sclerotinia sclerotiorum; rust, caused by
Uromyces fabae; and numerous aphid transmitted viruses. Lentil is also highly susceptible to several species of
Orabanche prevalent in the Mediterranean region, for which there does not appear to be much resistance in the germplasm. Plant breeders
and geneticists have addressed these stresses by identifying resistant/tolerant germplasm, determining the genetics involved
and the genetic map positions of the resistant genes. To this end progress has been made in mapping the lentil genome and
several genetic maps are available that eventually will lead to the development of a consensus map for lentil. Marker density
has been limited in the published genetic maps and there is a distinct lack of co-dominant markers that would facilitate comparisons
of the available genetic maps and efficient identification of markers closely linked to genes of interest. Molecular breeding
of lentil for disease resistance genes using marker assisted selection, particularly for resistance to Ascochyta blight and
Anthracnose, is underway in Australia and Canada and promising results have been obtained. Comparative genomics and synteny
analyses with closely related legumes promises to further advance the knowledge of the lentil genome and provide lentil breeders
with additional genes and selectable markers for use in marker assisted selection. Genomic tools such as macro and micro arrays,
reverse genetics and genetic transformation are emerging technologies that may eventually be available for use in lentil crop
improvement. 相似文献
2.
Breeding for resistance to lentil Ascochyta blight 总被引:1,自引:0,他引:1
Ascochyta blight, caused by Ascochyta lentis, is one of the most globally important diseases of lentil. Breeding for host resistance has been suggested as an efficient means to control this disease. This paper summarizes existing studies of the characteristics and control of Ascochyta blight in lentil, genetics of resistance to Ascochyta blight and genetic variations among pathogen populations (isolates). Breeding methods for control of the disease are discussed. Six pathotypes of A. lentis have been reported. Many resistant cultivars/lines have been identified in both cultivated and wild lentil. Resistance to Ascochyta blight in lentil is mainly under the control of major genes, but minor genes also play a role. Current breeding programmes are based on crossing resistant and high‐yielding cultivars and multilocation testing. Gene pyramiding, exploring slow blighting and partial resistance, and using genes present in wild relatives will be the methods used in the future. Identification of more sources of resistance genes, good characterization of the host‐pathogen system, and identification of molecular markers tightly linked to resistance genes are suggested as the key areas for future study. 相似文献
3.
Chickpea (Cicer arietinum L.) production has remained static for the past two decades. One major limiting factor has been susceptibility of cultivars to several biotic and abiotic stresses that adversely affect yield. In recent years, cultivars resistant to Ascochyta blight (Ascochyta rabiei [Pass.] Lab.), Fusarium wilt (Fusarium oxysporum f. sp. ciceris), and cold have been bred and released in many countries. Some progress has been made in breeding for resistance to drought, insects, and cyst nematode, but not for viruses, heat, and salinity. Two or more stresses are of equal importance in most chickpea growing areas. Therefore, future efforts should be directed toward the development of cultivars with multiple-stress resistance. Proper understanding of important stresses in different countries and the genetics of resistance should lead to more systematic approaches to resistance breeding. Wild Cicer species hold promise and deserve attention in resistance breeding. 相似文献
4.
B. Tar'an L. Buchwaldt A. Tullu S. Banniza T.D. Warkentin A. Vandenberg 《Euphytica》2003,134(2):223-230
Ascochyta blight caused by the fungus Ascochyta lentis Vassilievsky and anthracnose caused by Colletotrichum truncatum [(Schwein.) Andrus & W.D. Moore] are the most destructive diseases of lentil in Canada. The diseases reduce both seed yield
and seed quality. Previous studies demonstrated that two genes, ral1 and AbR1, confer resistance toA. lentis and a major gene controls the resistance to 95B36 isolate of C. truncatum. Molecular markers linked to each gene have been identified. The current study was conducted to pyramid the two genes for
resistance to ascochyta blight and the gene for resistance to anthracnose into lentil breeding lines. A population (F6:7) consisting of 156 recombinant inbred lines (RILs) was developed from across between ‘CDC Robin’ and a breeding line ‘964a-46’.
The RILs were screened for reaction to two isolates (A1 and 3D2) ofA. lentis and one isolate (95B36) ofC. truncatum. χ2 analysis of disease reactions demonstrated that the observed segregation ratios of resistant versus susceptible fit the two
gene model for resistance to ascochyta blight and a single gene model for resistance to anthracnose. Using markers linked
to ral1 (UBC 2271290), to AbR1(RB18680) and to the major gene for resistance to anthracnose (OPO61250),respectively, we confirmed that 11 RILs retained all the three resistance genes. More than 82% of the lines that had either
or both RB18680 and UBC2271290markers were resistant to 3D2 isolate and had a mean disease score lower than 2.5. By contrast, 80% of the lines that had
none of the RAPD markers were susceptible and had a mean disease score of 5.8. For the case of A1 isolate of A. lentis, more than 74% of the lines that carriedUBC2271290 were resistant, whereas more than 79% of the lines that do not have the marker were susceptible. The analysis of the RILs
usingOPO61250 marker demonstrated that 11out of 72 resistant lines carried the marker, whereas 66 out of 84 susceptible lines had the marker
present. Therefore, selecting materials with both markers for resistance to ascochyta blight and a marker for resistance to
anthracnose can clearly make progress toward resistance in the population.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
A. M. Torres B. Román C. M. Avila Z. Satovic D. Rubiales J. C. Sillero J. I. Cubero M. T. Moreno 《Euphytica》2006,147(1-2):67-80
Summary Faba beans are adversely affected by numerous fungal diseases leading to a steady reduction in the cultivated area in many
countries. Major diseases such as Ascochyta blight (Ascochyta fabae), rust (Uromyces viciae-fabae), chocolate spot (Botrytis fabae), downy mildew (Peornospora viciae) and foot rots (Fusarium spp.) are considered to be the major constraints to the crop. Importantly, broomrape (Orobanche crenata), a very aggressive parasitic angiosperm, is the most damaging and widespread enemy along the Mediterranean basin and Northern
Africa. Recent mapping studies have allowed the identification of genes and QTLs controlling resistance to some of these diseases.
In case of broomrape, 3 QTLs explained more than 70% of the phenotypic variance of the trait. Concerning Ascochyta, two QTLs
located in chromosomes 2 and 3 explained 45% of variation. A second population sharing the susceptible parental line also
revealed two QTLs, one of them likely sharing chromosomal location and jointly contributing with a similar percentage of the
total phenotypic variance. Finally, several RAPD markers linked to a gene determining hypersensitive resistance to race 1
of the rust fungus U. viciae-fabae have also been reported. The aim of this paper is to review the state of the art of gene technology for genetic improvement
of faba bean against several important biotic stresses. Special emphasis is given on the application of marker technology,
and Quantitative Trait Loci (QTL) analysis for Marker-Assisted Selection (MAS) in the species. Finally, the potential use
of genomic tools to facilitate breeding in the species is discussed. The combined approach should expedite the future development
of lines and cultivars with multiple disease resistance, one of the top priorities in faba bean research programs. 相似文献
6.
Mahboob A. Chowdhury Chandra P. Andrahennadi Alfred E. Slinkard Albert Vandenberg 《Euphytica》2001,118(3):331-337
Resistance to ascochyta blight of lentil (Lens culinaris Medikus),caused by the fungus Ascochyta lentis, is determined by a single recessive gene, ral
2, in the lentil cultivar Indian head. Sixty F2 individuals from a cross between Eston (susceptible) and Indian head (resistant) lentil were analyzed for the presence of
random amplified polymorphic DNA (RAPD) markers linked to the ral
2gene, using bulked segregant analysis (BSA). Out of 800 decanucleotide primers screened, two produced polymorphic markers
that co-segregated with the resistance locus. These two RAPD markers, UBC2271290and OPD-10870, flanked and were linked in repulsion phase to the gene ral
2 at 12 cm and 16 cm, respectively. The RAPD fragments were converted to SCAR markers. The SCAR marker developed from UBC2271290 could not detect any polymorphism between the two parents or in the F2. The SCAR marker developed from OPD-10870 retained its polymorphism. The polymorphic RAPD marker UBC2271290 and the SCAR marker developed from OPD-10870 can be used together in a marker assisted selection program for ascochyta blight resistance in lentil.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
The inheritance of resistance to lentil (Lens culinaris Medik.) vascular wilt caused by Fusarium oxysporum f.sp. lentis was investigated in a cross between resistant (ILL5588) and susceptible (L692–16-l(s)) lines. F2:4 progenies and F6:8, F6:9 recombinant inbred line (RIL) populations were assessed for their wilt reaction for three seasons in a well-established wilt-sick plot. Resistance to wilt was conditioned by a single dominant gene in the populations studied. The map location of the Fw locus was identified for the first time through linkage to a random amplified polymorphic DNA (RAPD) marker (OPK-15900) at 10.8 cM. Two other RAPD markers (OP-BH800 and OP-DI5500) identified by bulked segregant analysis were associated in the coupling phase with the resistance trait, and another marker (OP-C04650) was associated with repulsion. The DNA markers reported here will provide a starting point in marker-assisted selection for vascular wilt resistance in lentil. 相似文献
8.
Teresa Millan Heather J. Clarke Kadambot H. M. Siddique Hutokshi K. Buhariwalla Pooran M. Gaur Jagdish Kumar Juan Gil Guenter Kahl Peter Winter 《Euphytica》2006,147(1-2):81-103
Summary Chickpea is a cool season grain legume of exceptionally high nutritive value and most versatile food use. It is mostly grown
under rain fed conditions in arid and semi-arid areas around the world. Despite growing demand and high yield potential, chickpea
yield is unstable and productivity is stagnant at unacceptably low levels. Major yield increases could be achieved by development
and use of cultivars that resist/tolerate abiotic and biotic stresses. In recent years the wide use of early maturing cultivars
that escape drought stress led to significant increases in chickpea productivity. In the Mediterranean region, yield could
be increased by shifting the sowing date from spring to winter. However, this is hampered by the sensitivity of the crop to
low temperatures and the fungal pathogen Ascochyta rabiei. Drought, pod borer (Helicoverpa spp.) and the fungus Fusarium oxysporum additionally reduce harvests there and in other parts of the world. Tolerance to rising salinity will be a future advantage
in many regions. Therefore, chickpea breeding focuses on increasing yield by pyramiding genes for resistance/tolerance to
the fungi, to pod borer, salinity, cold and drought into elite germplasm. Progress in breeding necessitates a better understanding
of the genetics underlying these traits. Marker-assisted selection (MAS) would allow a better targeting of the desired genes.
Genetic mapping in chickpea, for a long time hampered by the little variability in chickpea’s genome, is today facilitated
by highly polymorphic, co-dominant microsatellite-based markers. Their application for the genetic mapping of traits led to
inter-laboratory comparable maps. This paper reviews the current situation of chickpea genome mapping, tagging of genes for
ascochyta blight, fusarium wilt resistance and other traits, and requirements for MAS. Conventional breeding strategies to
tolerate/avoid drought and chilling effects at flowering time, essential for changing from spring to winter sowing, are described.
Recent approaches and future prospects for functional genomics of chickpea are discussed. 相似文献
9.
The genetics of resistance to Ascochyta blight (Ascochyta fabae f. sp. fabae) was studied in two populations of faba bean (Vicia faba). Plants of a resistant population, ILB 752, and a susceptible one, NEB 463, were screened for their reaction to the pathogen
and the results were quantified on a scale of 0–5. Crosses were made between plants both within and between accessions and
the F1 and F2 generations assessed in a field trial 21 and 45 days after inoculation. Disease scores were greater at 45 days than at 21
days and they were not significantly affected by the presence of susceptible spreader rows in part of the trial. ILB 752 carried
a major dominant gene conferring resistance while NEB 463 carried the recessive allele for susceptibility. Furthermore, a
minority of plants of NEB 463 appeared to carry at least one pair of complementary recessive genes, also conferring resistance.
Most of the plants of ILB 752 were homozygous for the dominant resistance gene and a few were heterozygous. Reciprocal crosses
behaved identically, indicating the absence of maternal effects in the expression of Ascochyta blight resistance in faba beans.
The results show that it is important to confirm the level of heterozygosity for the resistance genes in this partially outbreeding
species before crossing is commenced. The major dominant gene for resistance, identified in ILB 752, has clear potential for
use in breeding for Ascochyta blight resistance. The minor genes identified in NEB 463 also show the potential for accumulating
resistance through mass selection.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Bernard Tivoli Alain Baranger Carmen M. Avila Sabine Banniza Martin Barbetti Weidong Chen Jenny Davidson Kurt Lindeck Mohammed Kharrat Diego Rubiales Mohamed Sadiki Josefina C. Sillero Mark Sweetingham Fred J. Muehlbauer 《Euphytica》2006,147(1-2):223-253
Summary Necrotrophic pathogens of the cool season food legumes (pea, lentil, chickpea, faba bean and lupin) cause wide spread disease
and severe crop losses throughout the world. Environmental conditions play an important role in the development and spread
of these diseases. Form of inoculum, inoculum concentration and physiological plant growth stage all affect the degree of
infection and the amount of crop loss. Measures to control these diseases have relied on identification of resistant germplasm
and development of resistant varieties through screening in the field and in controlled environments. Procedures for screening
and scoring germplasm and breeding lines for resistance have lacked uniformity among the various programs worldwide. However,
this review highlights the most consistent screening and scoring procedures that are simple to use and provide reliable results.
Sources of resistance to the major necrotrophic fungi are summarized for each of the cool season food legumes. Marker-assisted
selection is underway for Ascochyta blight of pea, lentil and chickpea, and Phomopsis blight of lupin. Other measures such
as fungicidal control and cultural control are also reviewed. The emerging genomic information on the model legume, Medicago truncatula, which has various degrees of genetic synteny with the cool season food legumes, has promise for identification of closely
linked markers for resistance genes and possibly for eventual map-based cloning of resistance genes. Durable resistance to
the necrotrophic pathogens is a common goal of cool season food legume breeders. 相似文献
11.
Summary Three lentil genotypes resistant to Fusarium oxysporum f.sp. lentis viz. Pant L 234, JL 446 and LP 286 were crossed with two susceptible ones. The hybrid plants were all resistant in the eight crosses evaluated. Segregation pattern for wilt reaction in F2, BC(P1), BC(P2) and F3 generations in field and glasshouse conditions indicated that resistance to Fusarium wilt is under the control of two dominant duplicate genes in Pant L 234 and two independent dominant genes with complementary effects in JL 446 and LP 286. A third dominant gene complementary to the dominant genes in JL 446 and LP 286 is present in two susceptible lines. Allelic tests suggest the presence of five independently segregating genes for resistance. Duplicate dominant genes in Pant L 234 are non-allelic to two dominant genes with complementary effects in LP 286 and JL 446 and the third gene complementary to the two genes in JL 446 and LP 286 in susceptible lines JL 641 and L 9–12. Gene symbols among parental genotypes have been designated. 相似文献
12.
Common bean breeding for resistance against biotic and abiotic stresses: From classical to MAS breeding 总被引:1,自引:1,他引:1
Summary Breeding for resistance to biotic and abiotic stresses of global importance in common bean is reviewed with emphasis on development
and application of marker-assisted selection (MAS). The implementation and adoption of MAS in breeding for disease resistance
is advanced compared to the implementation of MAS for insect and abiotic stress resistance. Highlighted examples of breeding
in common bean using molecular markers reveal the role and success of MAS in gene pyramiding, rapidly deploying resistance
genes via marker-assisted backcrossing, enabling simpler detection and selection of resistance genes in absence of the pathogen,
and contributing to simplified breeding of complex traits by detection and indirect selection of quantitative trait loci (QTL)
with major effects. The current status of MAS in breeding for resistance to angular leaf spot, anthracnose, Bean common mosaic and Bean common mosaic necrosis viruses, Beet curly top virus, Bean golden yellow mosaic virus, common bacterial blight, halo bacterial blight, rust, root rots, and white mold is reviewed in detail. Cumulative mapping
of disease resistance traits has revealed new resistance gene clusters while adding to others, and reinforces the co-location
of QTL conditioning resistance with specific resistance genes and defense-related genes. Breeding for resistance to insect
pests is updated for bean pod weevil (Apion), bruchid seed weevils, leafhopper, thrips, bean fly, and whitefly, including
the use of arcelin proteins as selectable markers for resistance to bruchid seed weevils. Breeding for resistance to abiotic
stresses concentrates on drought, low soil phosphorus, and improved symbiotic nitrogen fixation. The combination of root growth
and morphology traits, phosphorus uptake mechanisms, root acid exudation, and other traits in alleviating phosphorus deficiency,
and identification of numerous QTL of relatively minor effect associated with each trait, reveals the complexity to be addressed
in breeding for abiotic stress resistance in common bean. 相似文献
13.
Summary Kabuli chickpea (Cicer arietinum L.) is the common cultivated type of chickpea in arid and semi-arid environments in the Mediterranean region. Ascochyta blight, (Ascochyta rabiei (Pass.) Labr.), leaf miner (Liriomyza cicerina, Rond.) and cold, are the three most important stresses on chickpea grown under semi-arid conditions in this region. Phenotypic frequencies for responses to these stresses in the eight major chickpeagrowing regions of the world were estimated from 5,672 kabuli chickpea accessions assembled from these regions. In addition, the accessions were evaluated for 12 morpho-physiological and three phenological characters under semi-arid Mediterranean conditions at the International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria. Considerable regional differences in frequency distributions for response to the three stresses were observed. Average phenotypic diversity for responses to the three stresses was lower (Ho=0.474) than for morpho-physiological (Ho=0.754) and phenological (Ho=0.812) characters. The highest frequencies of accessions resistance to Ascochyta-blight and leaf-miner were found in South Asia and South Central Asia, respectively. A small number of chickpea breeding materials of ICARDA showed a moderate level of tolerance to cold. A group of four characters showing the strongest bivariate association with each of the three stresses was identified from the latter group. Then, a discrete multivariate log-linear analysis of the five-way frequency table was performed for each group. The simplest log-linear model for each group included both two- and three-factor association terms, but no independent factors. This suggested the potential for indirect selection for stress tolerance using one or more of these associated characters. The roles of these characters in ideotype breeding of kabuli chickpea for arid and semi-arid Mediterranean conditions deserves careful assessment. 相似文献
14.
The economic importance and current progress made in studies of the host-parasite relationship and identification of sources of resistance and breeding strategies of some important biotic diseases of pea are reviewed in this paper. The root rot complex caused by Rhizoctonia solani, Fusarium solani, Aphanomyces euteiches, Pythium ultimum and Fusarium oxysporum f. sp. pisi, race 1 and 2 has been reported from all commercial pea growing areas of the world. Adequate sources of resistance have been identified and there has been impressive success in the control of the Fusarium wilt pathogen following the introduction of wilt-resistant cultivars. Leaf and stem diseases of pea caused by the Ascochyta complex, Peronospora viciae and Erysiphe pisi are prevalent in most temperate pea growing regions of the world. Several sources of resistance are available, some of which are surprisingly durable. The biochemical genetic parameters of phenolic content used for assaying resistance to Erysiphe pisi offers an alternative method of evaluating breeding material. Wild relatives of pea (Pisum fulvum and P. humile) are valuable additional sources of genetic variation and provide good sources of resistance to pests and diseases. In temperate rainfed pea growing areas of southern Australia, pea seed yield is more closely related to dry matter production than harvest index. Tall and leafy cultivars proved more productive than afila types. 相似文献
15.
Early blight (Alternatia solani) is a fungal disease in hot and humid environments, which causes leaf, stem and tuber lesions. Early blight resistance should be incorporated into potato cultivars because the fungicide spraying is an expensive solution for developing countries. The diploid cultivated species Solanum tuberosum group Phureja and group Stenotomum are sources of resistance alleles. The elucidation of the inheritance for early blight resistance must help to decide what could be the best breeding procedure to improve this diploid germplasm and transfer the resistance to the tetraploid level. Three experiments were carried out under controlled and field conditions to determine the heritability of this trait using nested and diallel mating designs with haploid, species and haploid-species hybrids. The narrow-sense heritability estimates were relatively high (0.64–0.78). This means that additivity was the most important type of gene action for determining resistance to early blight at the diploid level. The results suggested that diploid parents showing highest levels of resistance, throughout the cycle of disease development, can be used in 4x×2x crosses to obtain resistant tetraploid progenies to this fungal disease. 相似文献
16.
Tosh Garg B. P. Mallikarjuna Mahendar Thudi Srinivasan Samineni Sarvjeet Singh J. S. Sandhu Livinder Kaur Inderjit Singh Asmita Sirari Ashwani K. Basandrai Daisy Basandrai Rajeev K. Varshney Pooran M. Gaur 《Euphytica》2018,214(3):45
Fusarium wilt (FW; caused by Fusarium oxysporum f. sp. ciceris) and Ascochyta blight (AB; caused by Ascochyta rabiei) are two major biotic stresses that cause significant yield losses in chickpea (Cicer arietinum L.). In order to identify the genomic regions responsible for resistance to FW and AB, 188 recombinant inbred lines derived from a cross JG 62 × ICCV 05530 were phenotyped for reaction to FW and AB under both controlled environment and field conditions. Significant variation in response to FW and AB was detected at all the locations. A genetic map comprising of 111 markers including 84 simple sequence repeats and 27 single nucleotide polymorphism (SNP) loci spanning 261.60 cM was constructed. Five quantitative trait loci (QTLs) were detected for resistance to FW with phenotypic variance explained from 6.63 to 31.55%. Of the five QTLs, three QTLs including a major QTL on CaLG02 and a minor QTL each on CaLG04 and CaLG06 were identified for resistance to race 1 of FW. For race 3, a major QTL each on CaLG02 and CaLG04 were identified. In the case of AB, one QTL for seedling resistance (SR) against ‘Hisar race’ and a minor QTL each for SR and adult plant resistance against isolate 8 of race 6 (3968) were identified. The QTLs and linked markers identified in this study can be utilized for enhancing the FW and AB resistance in elite cultivars using marker-assisted backcrossing. 相似文献
17.
Twenty-two improved and local cassava genotypes were evaluated for their bacterial blight symptom types in reaction to infection
by Xanthomonas axonopodis pv. manihotis under field conditions in the forest, forest savanna transition and wet savanna zones of Togo. High genotype × environment
interactions in development of each symptom type were observed. Combining data on environments and genotypes, spot, blight
and wilt symptoms were positively correlated. Analysing genotype reactions across environments, indications for independent
mechanisms of resistance on leaf and stem level, varying by genotype, were found. Genotypes Main27 with resistance to spot
and blight symptoms and TMS4(2)1425 with resistance to wilt symptoms are recommended to breeders to introgress their resistance
characteristics. Significant negative correlations were generally observed between blight and wilt symptom development and
root yield across ecozones, with blight being more important under lower, and wilt under higher inoculum pressure. Genotypes
TMS30572, CVTM4, TMS92/0429 and TMS91/02316 showed low spot, blight and wilt symptoms combined with high root yield across
ecozones. 相似文献
18.
Brian J. Steffenson 《Euphytica》1992,63(1-2):153-167
Summary Since the mid-1940's, barley cultivars grown in the northern Great Plains of the USA and Canada have been resistant to stem rust caused byPuccinia graminis f. sp.tritici. This durable resistance is largely conferred by a single gene,Rpg1, derived from a single plant selection of the cultivar Wisconsin 37 and an unimproved Swiss cultivar. At the seedling stage, barley genotypes withRpg1 generally exhibit low mesothetic reactions at 16–20° C and slightly higher mesothetic reactions at 24–28° C to many stem rust pathotypes. This resistance is manifested by a low level of rust infection and mostly incompatible type uredia on adult plants.Rpg1 reacts in a pathotype-specific manner since some genotypes ofP. g. f. sp.tritici are virulent on cultivars carrying this gene in the field. Several factors may have contributed to the longevity of stem rust resistance in barley, a) since barley is planted early and matures early, it can sometimes escape damage from stem rust inoculum carried from the south; b) one or more minor genes may augment the level of resistance already provided byRpg1; c) the cultivation of resistant wheat cultivars and eradication of barberry have reduced the effective population size and number of potential new pathotypes ofP. g. f. sp.tritici, respectively; and d) virulent pathotypes ofP. g. f. sp.tritici andP. g. f. sp.secalis have not become established. This situation changed in 1989 when a virulent pathotype (Pgt-QCC) ofP. g. f. sp.tritici became widely distributed over the Great Plains. However,Rpg1 may still confer some degree of resistance to pathotype QCC because stem rust severities have been low to moderate and yield losses light on barley cultivars carrying the gene during the last four seasons (1989–1992). Several sources of incomplete resistance to pathotype QCC have been identified in barley. To facilitate the transfer of resistance genes from these sources into advanced breeding lines, molecular marker assisted selection is being employed. 相似文献
19.
Alessandro Infantino Mohamed Kharrat Luca Riccioni Clarice J. Coyne Kevin E. McPhee Niklaus J. Grünwald 《Euphytica》2006,147(1-2):201-221
Summary Soil-borne fungal diseases are among the most important factors, limiting the yield of grain legumes in many countries worldwide.
Root rot, caused by Aphanomyces euteiches, Rhizoctonia solani, Fusarium solani and wilt, caused by several formae speciales of Fusarium oxysporum are the most destructive soil-borne diseases of pea, chickpea, lentil, fababean and lupin. The most effective control of
these diseases is achieved through the use of resistant varieties. In this paper, recent advances in conventional and innovative
screening methods for disease resistance are presented. Many grain legume accessions, which are maintained in national and
international germplasm collections, have been evaluated for disease resistance and numerous resistant varieties have been
released following incorporation of identified resistance genes from these sources. Recent identification of molecular markers
tightly linked to resistance genes has greatly enhanced breeding programs by making marker assisted selection (MAS) possible
and allowing the development of varieties with multiple disease resistance. Progress in the understanding of the biology of
soil-borne fungal pathogens of grain legumes is also reviewed with particular reference to the genetic structure of their
populations, diagnosis and host–pathogen interaction. 相似文献
20.
R. N. Sawhney 《Euphytica》1987,36(1):49-54
Summary Variation for resistance toPuccinia graminis f.sp.tritici, P. recondita f.sp.tritici andP. striiformis was induced in theTriticum aestivum cultivar Lalbahadur using nitrosomethyl urea. Variations were isolated from the M2 population in the post-seedling stage in the field when infected with a mixture of races of each of the three rusts. Plants exhibiting simultaneous resistance to stem rust, leaf rust and yellow rust were indentified. Repeated screening in the subsequent generations confirmed the resistance of the mutant lines that are morphologically similar to the parental cultivar. The rust resistance of 20 mutant lines was also confirmed at the seedling stage using individual races of stem rust and leaf rust. The different patterns observed in the mutant lines tested against a wide range of races show that these lines can be used as components of a multiline. The patterns of variation compared with those of the known genes for resistance against the Indian races of the pathogens suggest that the mutations for rust resistance are due to factor different from those already known in bread wheat, providing a broadened genetic base for future breeding programmes. 相似文献