Resistance to ascochyta blights of cool season food legumes (original) (raw)
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Genetics of ascochyta blight resistance in chickpea
Euphytica, 2009
Genetics of resistance to ascochyta blight was studied using different generations of fifteen crosses of chickpea (Cicer arietinum L.). Six parents comprising two susceptible varieties GL 769, C 214 and four resistant lines GG 1267, GL 90168, GL 96010 and GL 98010 were used to develop one S 9 S, eight S 9 R and six R 9 R crosses and some of the back crosses and F 3 generations were developed. Field screening technique was used to evaluate the different generations for disease reaction using mixture of ten prevalent isolates (ab 1-ab 10) of ascochyta blight (Ascochyta rabiei). Inheritance study showed digenic recessive control of resistance in the cross GL 769 9 C 214, whereas monogenic recessive control of resistance was found in the crosses GL 769 9 GL 98010 and C 214 9 GL 98010. Digenic dominant and recessive control of resistance was found in the crosses GL 769 9 GG 1267 and C 214 9 GG 1267 while the crosses GL 769 9 GL 90168 and C 214 9 GL 96010 showed the monogenic dominant control of resistance. Trigenic dominant and recessive control of resistance was observed in the crosses GL 769 9 GL 96010 and C 214 9 GL 90168. Allelic relationship studies showed that three resistant parents viz., GG 1267, GL 96010 and GL 90168 possessed allelic single dominant gene for resistance. Besides, GG 1267 possessed two minor recessive genes for resistance, one of them was allelic to the minor recessive gene possessed by GL 90168 and other with GL 96010. The resistant parents GL 90168 and GL 96010 possessed non-allelic minor gene for resistance. The resistant parent GL 98010 possessed two minor recessive genes for resistance which were allelic to respective single recessive gene for resistance possessed by the susceptible parents GL 769 and C 214. The susceptible parents GL 769 and C 214 also possessed single independent inhibitory dominant susceptibility gene. The inhibitory gene was epistatic to the corresponding recessive gene for resistance.
Plant Breeding, 2006
Quantitative trait locus (QTL) analysis of ascochyta blight resistance in lentil was conducted using genomic maps developed from two F 2 populations, viz. ILL5588/ILL7537 and ILL7537/ILL6002. Five QTLs for ascochyta blight resistance were identified by composite interval mapping (CIM) across four linkage groups (LG) in population ILL5588/ILL7537. Three QTLs were identified by CIM in population ILL7537/ILL6002 (two in close proximity on LGI and one on LGII). Two of these coincided with regions identified using multiple interval mapping (MIM) and were shown to be conditioned by dominant and partial dominant gene action. Together, they accounted for approximately 50% of the phenotypic variance of disease severity. Comparison between the two populations revealed a potentially common QTL and several common regions that contained markers significantly associated with resistance. This study demonstrated the transferability of QTLs among populations and identified markers closely linked to the major QTL that may be useful for future marker-assisted selection for disease resistance.
Euphytica, 2006
Ascochyta blight (AB) is a consistent problem affecting large growing areas of chickpea in all countries where this crop is cultivated. This disease is capable of causing large yield losses under conducive environmental conditions. To characterize the genetics of resistance to AB in chickpea, a population consisting of 77 recombinant inbred lines (RILs) derived from an inter-specific cross of Cicer arietinum (FLIP84-92C, resistant parent) x Cicer reticulatum Lad. (PI 599072, susceptible parent) was used. Each RIL and the parents were inoculated with blight spores by spraying. The RILs were scored for disease reactions under greenhouse conditions at 20 °C in a 12 h photoperiod. A linkage map was constructed using RAPD markers. Eleven linkage groups were obtained, of which three were small. The map spanned 889.1 cM with an average marker density of 10.1 cM. Two QTL were detected on linkage groups 1 and 4, which together explained 31% of the total phenotypic variation for AB resistance. These markers can improve precision of molecular breeding in this population.
Identification and Mapping of QTLs Conferring Resistance to Ascochyta Blight in Chickpea
Crop Science, 2000
Ascochyta blight, caused by Ascochyta rabiei (Pass.) Lab., is a cently, showed that two compledevastating disease of chickpea (Cicer arietinum L.) worldwide. Resistant germplasm has been identified and the genetics of resistance has mentary recessive genes conferred resistance. However, been the subject of numerous studies. The objectives of the present the locations of the genes conferring resistance are not study were to determine the genetics of resistance to ascochyta blight known. Since multiple genes appear to condition resisof chickpea and to map and tag the chromosomal regions involved tance, knowledge of their genomic locations and linkage using molecular markers. We used a set of 142 F 5:6 recombinant inbred to molecular markers would facilitate gene transfer and lines (RILs) obtained from an interspecific cross of C. arietinum pyramiding of the genes into acceptable genetic back-(FLIP84-92C, resistant parent) ϫ C. reticulatum Lad. (PI 599072, grounds through marker-assisted selection. susceptible parent). The RILs were scored for disease reactions in Molecular markers have been used to establish linkthe field over 2 yr and were genotyped for polymorphic molecular age maps for many crop species (O'Brien, 1993) and markers [isozyme, random amplified polymorphic DNA (RAPD), they have been utilized to determine gene number for and inter simple sequence repeat (ISSR)] in the laboratory. The disease was scored quantitatively and data were used for QTL analysis. particular traits and for gene tagging (Paterson et al., A linkage map was established that comprised nine linkage groups 1991; Lee, 1995). Many important disease resistance containing 116 markers covering a map distance of 981.6 centimorgans genes have been mapped and tagged in various crops (cM) with an average distance of 8.4 cM between markers. Two (Staub et al., 1996; Mohan et al., 1997). RAPD markers quantitative trait loci (QTLs), QTL-1 and QTL-2, conferring resis-(Williams et al., 1990; Welsh and McClelland, 1990) are tance to ascochyta blight, were identified which accounted for 50.3 simple and fast and have been employed widely for and 45.0% of the estimated phenotypic variation in 1997 and 1998, mapping genomes (Torres et al., 1993; Hunt and Page, respectively, and were mapped to linkage groups 6 and 1, respectively. 1995) and for tagging resistance genes (Staub et al., Two RAPD markers flanked QTL-1 and were 10.9 cM apart while 1996; Mohan et al., 1997; Mayer et al., 1997).
Frontiers in Plant Science, 2022
Ascochyta blight (AB), caused by the fungal pathogen Ascochyta rabiei, is a devastating foliar disease of chickpea (Cicer arietinum L.). The genotyping-by-sequencing (GBS)based approach was deployed for mapping QTLs associated with AB resistance in chickpea in two recombinant inbred line populations derived from two crosses (AB 3279 derived from ILC 1929 × ILC 3279 and AB 482 derived from ILC 1929 × ILC 482) and tested in six different environments. Twenty-one different genomic regions linked to AB resistance were identified in regions CalG02 and CalG04 in both populations AB 3279 and AB 482. These regions contain 1,118 SNPs significantly associated with AB resistance (p ≤ 0.001), which explained 11.2-39.3% of the phenotypic variation (PVE). Nine of the AB resistance-associated genomic regions were newly detected in this study, while twelve regions were known from previous AB studies. The proposed physical map narrows down AB resistance to consistent genomic regions identified across different environments. Gene ontology (GO) assigned these QTLs to 319 genes, many of which were associated with stress and disease resistance, and with most important genes belonging to resistance gene families such as leucine-rich repeat (LRR) and transcription factor families. Our results indicate that the flowering-associated gene GIGANTEA is a possible key factor in AB resistance in chickpea. The results have identified AB resistance-associated regions on the physical genetic map of chickpea and allowed for the identification of associated markers that will help in breeding of AB-resistant varieties.
Theoretical and Applied Genetics, 2004
Ascochyta blight in chickpea (Cicer arietinum L.) is a devastating fungal disease caused by the necrotrophic pathogen, Ascochyta rabiei (Pass.) Lab. To elucidate the genetic mechanism of pathotype-dependent blight resistance in chickpea, F 7-derived recombinant inbred lines (RILs) from the intraspecific cross of PI 359075(1) (blight susceptible) × FLIP84-92C(2) (blight resistant) were inoculated with pathotypes I and II of A. rabiei. The pattern of blight resistance in the RIL population varied depending on the pathotype of A. rabiei. Using the same RIL population, an intraspecific genetic linkage map comprising 53 sequence-tagged microsatellite site markers was constructed. A quantitative trait locus (QTL) for resistance to pathotype II of A. rabiei and two QTLs for resistance to pathotype I were identified on linkage group (LG)4A and LG2+6, respectively. A putative single gene designated as Ar19 (or Ar21d) could explain the majority of quantitative resistance to pathotype I. Ar19 (or Ar21d) appeared to be required for resistance to both pathotypes of A. rabiei, and the additional QTL on LG4A conferred resistance to pathotype II of A. rabiei. Further molecular genetic approach is needed to identify individual qualitative blight resistance genes and their interaction for pathotype-dependent blight resistance in chickpea.
Inheritance of Early and Late Ascochyta Blight Resistance in Wide Crosses of Chickpea
Genes
Chickpea (Cicer arietinum) is a globally important food legume but its yield is negatively impacted by the fungal pathogen Ascochyta blight (Ascochyta rabiei) causing necrotic lesions leading to plant death. Past studies have found that Ascochyta resistance is polygenic. It is important to find new resistance genes from the wider genepool of chickpeas. This study reports the inheritance of Ascochyta blight resistance of two wide crosses between the cultivar Gokce and wild chickpea accessions of C. reticulatum and C. echinospermum under field conditions in Southern Turkey. Following inoculation, infection damage was scored weekly for six weeks. The families were genotyped for 60 SNPs mapped to the reference genome for quantitative locus (QTL) mapping of resistance. Family lines showed broad resistance score distributions. A late responding QTL on chromosome 7 was identified in the C. reticulatum family and three early responding QTLs on chromosomes 2, 3, and 6 in the C. echinospermum...
Journal of Animal and Plant Sciences, 2017
Chickpea Blight is a devastating disease of chickpea (Cicer areitinum L.) worldwide caused by Ascochyta rabiei (Pass.) Lab. The disease is more disastrous particularly in long cool and humid environmental spells. It results in huge losses by wiping off all the crop in the desert areas whenever hit its epidemics. To manage this disease, different management strategies are practiced. However, breeding resistance to the host is the best and environmentally safe strategy. During 1970s, the loss of host resistance against the pathogen was reported, so extra ordinary efforts were started by the scientists to enhance the host tolerance towards the pathogen. In this way, relatively simple field screening techniques were followed for breeding and identification of new resistant genotypes. The review sums up the efforts regarding host breeding against chickpea blight involving large scale field screening experiments as well as recent marker assisted breeding using the molecular mapping and QTLs against the different strains of pathogen. Moreover, the important aspects covering the related knowledge of the pathogen, its biology, variability, perpetuation, characteristics and factor affecting the disease establishment have also been summarized.
Identification of Lentil Genotypes for Resistance to Ascochyta Blight (AscochytaLentis)
Journal of Plant Pathology & Microbiology, 2021
Ascochyta blight, caused by Ascochyta lentis, is one of the most globally important diseases of lentil. The disease is seed and air borne causing huge loss and development of ascochyta blight resistant varieties is most effective means of controlling this disease. The diseases of lentil not only reduce yield but also deteriorate seed quality. To date, no highly resistant sources of ascochyta blight in lentil have not been reported from the Ethiopian lentil breeding programme. Past efforts have been directed towards developing improved varieties with resistance to one or the other biotic stress, improving the seed size, color of seed cotyledon, market quality and shortening the crop duration to fit lentil in various cropping systems. And also breeding for host resistance has been suggested as an efficient means and sustainable to control this disease. In present study, total of sixty five lentil entries received from Austria, is one of our partners, were evaluated at Alemtena and Minjar naturally hot spot field condition during the year 2018-19 and 2019-20 to identify sources of genetic resistant against ascochyta blight disease incited by the fungus Ascochyta lentis. These entries were assigned in augmented design with two replications that of checks were replicated after every eight test entries for the comparison purpose. The spacing was 20 cm between rows with 4m row length. The disease severity was recorded three times at different growth stage every 21 days intervals using (1-9) point disease ratings scale. High variations were observed in resistance level among the tested genotypes ranged from resistant to highly susceptible. Based on the reactions, 7 genotypes were resistant, 15 were moderately resistant and other become susceptible to highly susceptible which is 10 and 30 lines, respectively at Alem Tena. In another hand, 1 was resistant, eight were moderately resistant, twelve were susceptible and forty one genotypes were highly susceptible at Minjar. The promising genotypes would be used as a source of parental materials in the next breeding stages. Ethiopia still has different opportunities for enhancing the productivity of lentil including varied agro ecology, diversity of grain legumes, population and urbanization trends, and increased demand for animal feed and processed foods. 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.