Resistant Chickpea Genotypes Research Articles

Genetic resources and genes/QTLs for gram pod borer (Helicoverpa armigera Hübner) resistance in chickpea from the Western Himalayas.

Helicoverpa armigera (also known as gram pod borer) is a serious threat to chickpea production in the world. A set of 173 chickpea genotypes were evaluated for H. armigera resistance, including mean larval population (MLP), percentage pod damage (PPD), and pest resistance (PR) for 2 consecutive years (year 2020 and 2021). The same core set was also genotyped with 50K AxiomCicerSNP Array. The trait data and 50,000 single nucleotide polymorphism genotypic data were used together to work out marker-trait associations (MTAs) using different genome-wide association studies models. For MLP, a total of 53 MTAs were identified, including 25 MTAs in year 2020 and 28 MTAs in year 2021. A set of three MTAs was found common in both environments. For PPD, two MTAs in year 2020 and five MTAs in year 2021 were identified. A set of two MTAs were common in both environments. Similarly, for PR, only two MTAs common in both environments were identified. Interestingly, a common MTA (Affx_123255526) on chromosome 2 (Ca2) was found to be associated with all the three component traits (MLP, PPD, and PR) of pod borer resistance in chickpea. Further, we report key genes that encode SCAMPs (that facilitates the secretion of defense-related molecules), quinone oxidoreductase (enables the production of reactive oxygen species that promotes diapause of gram pod borer), and NB-LRR proteins that have been implicated in plant defense against H. armigera. The resistant chickpea genotypes, MTAs, and key genes reported in the present study may prove useful in the future for developing pod borer-resistant chickpea varieties.

Expression analysis and characterization of resistance (R) genes in contrasting Fusarium wilt resistant chickpea genotypes

Fusarium wilt is one of the most notorious diseases of crop plants. This disease leads to huge crop losses in chickpea with substantial monetary value worldwide. The objective of the current study was to characterise Fusarium oxysporum f. sp. cicris (Foc), the causal agent of chickpea wilt, on morphological basis followed by the assessment of resistance of thirty chickpea germplasm accessions to Foc in a pot experiment. The second objective of this research was to study gene expression and characterisation of specific resistance (R) genes in different Fusarium wilt-resistant chickpea genotypes. The morphological identification and characterization of Foc was done by culturing the fungus potato dextrose agar (PDA) medium. Fusarium wild resistance was assessed by challenging 30 chickpea genotypes to artificial inoculum of Foc by using a pre-defined disease rating scale. Different resistance levels were showed by different chickpea genotypes ranging from highly resistant to highly susceptible. Two accessions demonstrated resistance, 15 were moderately resistant and the rest of the genotypes were moderately susceptible to susceptible. The in-silico expression analysis of R genes showed that two R genes, LOC101499430 and LOC101499568 were upregulated in chickpea roots, indicating their probable role in Fusarium wilt resistance. The genes were further assessed for their expression in response to Fusarium inoculation in contrasting Fusarium wilt resistant and susceptible chickpea genotypes. The resistant genotypes showed significantly higher expression levels of the selected R genes in comparison with susceptible genotypes. This study provides valuable insights into evaluating chickpea germplasm for Fusarium wilt resistance and identification of candidate resistance genes which could be employed for enhancement of Fusarium wilt resistance in chickpea.

Comparison of different screening methods for the selection of Ascochyta blight disease on chickpea (Cicer arietinum L.) genotypes.

Chickpea (Cicer arietinum L.) is the second most important edible food grain legume, widely grown all over the world. However, the cultivation and production of chickpea are mainly affected by the Ascochyta blight (AB) disease, which causes losses of up to 100% in areas with high humidity and warm temperature conditions. Various screening methods are used in the selection of chickpea genotypes for resistance to AB disease. These methods are natural field condition (NFC), artificial epidemic field condition (AEC), marker-assisted selection (MAS), and real-time PCR (RT-PCR). The study was conducted with 88 chickpea test genotypes between the 2014 and 2016 growing seasons. The results of the screening were used to sort the genotypes into three categories: susceptible (S), moderately resistant (MR), and resistant (R). Using MAS screening, 13, 21, and 54 chickpea genotypes were identified as S, MR, and R, respectively. For RT-PCR screening, 39 genotypes were S, 31 genotypes were MR, and 18 genotypes were R. In the AEC method for NFC screening, 7, 17, and 64 genotypes were S, MR, and R, while 74 and 6 genotypes were S and MR, and 8 genotypes were R-AB disease. As a result of screening chickpea genotypes for AB disease, it was determined that the most effective method was artificial inoculation (AEC) under field conditions. In the study, Azkan, ICC3996, Tüb-19, and Tüb-82 were determined as resistant within all methods for Pathotype 1.

Molecular screening for Fusarium oxysporum resistance genes in chickpeas

Root rot and wilt (Fusarium oxysporum) are the most common pathogens among grain legumes, which cause yield losses of 10 to 40%. Wilt caused by Fusarium oxysporum f.sp. ciceris is a devastating disease in chickpea growing area. In this study, 50 chickpea genotypes were studied to identify genetic sources of resistance to the disease in 2021 and 2022 vegetative seasons. The studies were carried out against the natural background of the experimental field at the Saimasai Agrotechnopark site of the Kazakh National Agrarian Research University, and the studies were carried out against an artificial background at the experimental site of Agropark Ontustik LLP located in the village of Zhalpaksay, Almaty region, Karasai district. The resistance and susceptibility of the plants to F. oxysporum were determined four weeks after artificial inoculation. In field trials, 70% of the genotypes were resistant to wilt and the remaining 30% showed susceptibility to the disease with varying degrees. Molecular methods were used to identify genetic sources of resistance. In the molecular analysis, all 50 genotypes were screened using the primers CaSTMS2, TA200, TA194, TA72, TA46, TR29 and TR7, which are closely related markers to resistance genes. Marker selection can identify resistant genes when screening chickpea genotypes for this pathogen. As a result of screening, resistant chickpea genotypes have been identified that can be used in the breeding program to develop F. oxysporum resistant chickpea varieties.

Standardization of detached leaf assay to screen chickpeas for resistance to beet armyworm, Spodoptera exigua (Hübner, 1808)

The beet armyworm, Spodoptera exigua (Hübner, 1808) is an important pest of several economically important crops, and recently emerged as a serious pest of chickpea in South Central India. We standardized a detached leaf assay technique to evaluate chickpea germplasm and segregating populations for resistance to this pest under laboratory conditions. Two chickpea genotypes ICCL 86111 and ICC 3137 grown under field and greenhouse conditions were used for the detached leaf assay at the vegetative and flowering stages. The terminal branches were infested with 5, 10, 15, and 20 neonate larvae of S. exigua. The test genotypes were also infested with 2, 4, 6 and 8 third-instar larvae at the podding stage. At the vegetative stage, ICCL 86111 suffered less damage than ICC 3137 across infestation levels. The differences in larval survival between the genotypes were significant, and larval survival was lower on ICCL 86111 than on ICC 3137 across infestation levels. The results suggested that infesting the chickpea terminal branches with 10–15 neonate larvae per branch at the vegetative stage or six third-instar larvae at the podding stage can be used to evaluate chickpea genotypes for resistance to S. exigua.

Ascochyta Blight in Chickpea: An Update.

Chickpea (Cicer arietinum L.), one of the most cultivated legumes worldwide, is crucial for the economy of several countries and a valuable source of nutrients. Yields may be severely affected by Ascochyta blight, a disease caused by the fungus Ascochyta rabiei. Molecular and pathological studies have not yet managed to establish its pathogenesis, since it is highly variable. Similarly, much remains to be elucidated about plant defense mechanisms against the pathogen. Further knowledge of these two aspects is fundamental for the development of tools and strategies to protect the crop. This review summarizes up-to-date information on the disease's pathogenesis, symptomatology, and geographical distribution, as well as on the environmental factors that favor infection, host defense mechanisms, and resistant chickpea genotypes. It also outlines existing practices for integrated blight management.

Advanced chickpea lines resistant against fusarium wilt (Fusarium oxysporum)

Fusarium wilt (FW) disease caused by Fusarium oxysporum f. sp. ciceris remains one of the major biotic stresses challenging chickpea production globally. Thus, to explore FW resistant chickpea genotypes; we tested a set of 75 advanced breeding lines including one FW susceptible check and one FW resistant check for two consecutive years 2016 and 2017 in FW (Foc2) infected sick plot. A total of 30 resistant lines, viz. IPC2005-45, IPC2005-19,IPC2010-03 and 34 moderately resistant, viz. IPC 2005-37, IPC 2004-08, IPC 2006-64 and 11 susceptible lines were identified based on the two year data. Thus, these identified resistant lines could be directly released for FW resistant variety or could serve as important donors for developing FW resistant chickpea cultivars.

Molecular marker validation and identification of Fusarium wilt resistant chickpea genotypes

Fusarium wilt is one of the most destructive biotic stress reducing chickpea productivity worldwide. As a step towards understanding the basis of wilt resistance in chickpea, we investigated the morpho-physiological and biochemical traits of 29 desi and 15 kabuli chickpea genotypes and screened these genotypes for fusarium wilt disease using gene based molecular markers. The number of branches per plant were significant and positively correlated with number of pods per plant (r=0.635) and number of seed per plant (r=0.556) at 1% significance level. Biochemical parameters related to stresses were also analyzed for proline (1.19-3.92 µ mol/g), sugar (23.6-37.4 mg/g), malondialdehyde (MDA) (1.1 -3.67 nmol/g) and hydrogen peroxide (H2O2) (10.4-21.5 µ mol/g) in seeds of these genotypes grown under normal field conditions. Molecular screening was done by using15 gene-based markers. Polymorphic Information Content (PIC) value was in the range of 0.221 to 0.695, respectively. The genotypes JG-63 and Vijay identified during the investigation could be included in the hybridization programs during development of high yielding and wilt resistant varieties. The molecular markers TA194, TA-59, TA-96, TR-19, TR-29 and TR-31 can be used as marker assisted breeding tools for screening, validation and development of fusarium wilt resistant chickpea genotypes.

Screening of large and extra-large seeded kabuli chickpea genotypes for resistance to fusarium wilt under scarce rainfall zone

30 genotypes were screened against Fusarium wilt at RARS, Nandyal in Fusarium wilt sick plot. The pathogen is both soil and seed borne and causes about 20-100 per cent losses in crop yield depending upon the stage of infection and incidence of wilt. The disease first appears in patches in the field which later spreads in the entire field. The most appropriate way to manage this disease is using the resistant varieties. For this purpose screening is conducted and the genotypes with resistant, moderately resistant and tolerant were found.

Comparative expression profile of some putative resistance genes of chickpea genotypes in response to ascomycete fungus, Ascochyta rabiei (Pass.) Labr.

Chickpea (Cicer arietinum L.) is one of the most important legumes infected with many pathogens including fungal pathogens. One of the most important devastating fungal pathogens in chickpea is Ascochyta rabiei (Pass.) Labr. which causes up to 100% reduction in yield. In the present work, the expression patterns of AFP-ca, CaD2, LRR and PGIP genes were studied in response to Ascochyta rabiei in two susceptible and resistant chickpea genotypes. The experimental system was conducted in greenhouse, for both inoculated and mock-inoculated plants (control). RNA was isolated from Icc 12004 (resistant) and FLIP 82-150c (susceptible) genotypes in 0, 6, 12, 24, 48, 72 and 96 h after inoculation. The expression of the genes was measured in susceptible and resistant plants via semiquantitative RT-PCR. Results showed higher expression of all three genes in resistant genotype compared with susceptible one. Results showed that the candidate genes from antimicrobial families (CaD2 and AFP-ca) were up-regulated in resistant genotypes at early hours after inoculation (6–24 hpi), and also for PGIP from galacturonase-inhibiting protein families, the maximum expression was observed at early hours of inoculation to 48 hpi. In general, we concluded that all genes studied in this investigation contribute to plant–pathogen interaction and all of them can increase the resistance responses to Ascochyta blight disease.

Spatial Distribution and Association of Chickpea Wilt/Root Rots Epidemicswith Biophysical Factors at West Shewa, Oromia Regional State, Ethiopia

Chickpea (Cicer arietinum L) is one of the important grain legume crops in Africa particularly in Ethiopia which widely grown in marginal soils and usually as rotational crops in highland and semi-highland regions of the country and also as a source of cash to the farmers and foreign currency in Ethiopia. However, its production is totally affected by many pest and diseases. Among biotic stresses, wilt or root rot diseases are considered as the major problems in chickpea production. Therefore, the present study was conducted to determine the assessment of chickpea wilts disease intensity, in West Shewa, Ethiopia. Field survey was carried out in purposively selected Kebeles of Ambo and Dendi districts of West Shewa, Ethiopia. The results of the study revealed that, among 70 chickpea fields surveyed in both districts, the overall mean prevalence and incidence of the disease were 92.9%, and 35.09%, respectively. The higher prevalence and incidence of the disease was recorded in Ambo district with 40.96% and 93.5%, respectively while, in Dendi district it was 29.10% and 92.3%, respectively. Therefore, proper weed management practices, planting improved varieties and other related farm practices should be carried out to reduce wilt or rot impact until resistant chickpea genotypes are developed and distributed to major chickpea production regions of the country. Effective and feasible integrated management options need to be developed on chickpea wilt/root rot diseases in the country. Keywords: Cicer

Screening Chickpea Genotypes for Resistance to Rhizoctonia bataticola in Controlled Conditions

Among the various biotic stresses, dry root rot caused by Rhizoctonia bataticola is becoming severe in most chickpea growing regions of India where the crop is grown under rain fed conditions causing 30-40 per cent yield loss. In this context, 520 chickpea genotypes were screened in the laboratory condition using Blotter Paper Technique to study the reaction of the genotypes to the Rhizoctonia bataticola and to identify resistance source for the disease. Among 520 genotypes, three were resistant viz., PG 06102, BG 2094 and IC 552137; 21 were moderate resistant viz., IC 15167, IC 2867, JAKI 9218, ICC 9023, ICC-14346, IC-269768, PG 01103, Pule 9801, KGD 120, NbeG 28, WR 315, IC-269488, IC 552198, IC 552178, IC 552132, IC 552320, IC 552214, IC 552232, CLH 29, IC 552102, IC 552224; 76 were moderate susceptible, 337 were susceptible and the rest eighty three were highly susceptible for dry root rot. The identified resistant genotypes may serve as potential donors in chickpea resistance breeding programme for dry root rot.

SCREENING OF PEAS (PISUM SATIVUM) VARIETIES/ LINES AGAINST FUSARIUM WILT (FUSARIUM OXYSPORUM .SP.PICI) AND IN VITRO EVALUATION OF FUNGICIDES AGAINST MYCELIAL GROWTH OF PATHOGEN

Twenty Peas (Pisum sativum L.) varieties/ lines were evaluated against Fusarium wilt caused by Fusarium oxysporum .Sp.pici by sowing them in sick plot during the year of 2016-17 at the Plant Pathology Research Institute, Faisalabad. Each cultivar/line was planted in a single row of three meter length, with plant to plant and row to row distances of 15cm and 30 cm respectively and replicated thrice by following Randomized Complete Block Design (RCBD). Out of these twenty varieties/ lines 13 including check variety Olympia were found highly susceptible ranging from 53.2 to 83.5% plant mortality. Six varieties/lines were susceptible ranging from 30.3 to 44.1 % plant mortality. Only a single variety Garrow performed as moderately resistant by showing 21% plant mortality in the field. Efficacy of five fungicides against Fusarium oxysporum .Sp.pici, at various concentrations was evaluated in-vitro and significant variations among treatments was observed. In general there was a significant decrease in mycelial growth of the fungus with an increase in concentration of fungicides. Tilt (Propiconazol),( Daconil (Chlorothalonil) and Crest (Carbendazim) were the most effective fungicides in inhibiting the growth of the fungus in descending order. The Tilt almost 90% inhibited the growth @ 50µg/ml concentration, Daconil and Crest exhibited intermediate effectiveness. Topsin-M (Thiophanate-methyl) and Score (Difenoconazole) were the least effective fungicides.Ahmad, M. A., S. M. Iqbal, N. Ayub, Y. Ahmad and A. Akram. 2010. Identification of resistant sources in chickpea against Fusarium wilt. Pak. J. Bot, 42: 417-426.Borum, D. E. and J. Sinclair. 1968. Evidence for systemic protection against Rhizoctonia solani with vitavax in cotton seedlings. Phytopathology, 58: 976-&.Davies, D., G. Berry, M. Heath and T. Dawkins. 1985. Pea (Pisum sativum L.). Grain Legume Crops. 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Pakistan Journal of Phaytopahtology, 4: 5-8.Iqbal, S. M. 2005. Screening of chickpea genotypes for resistance against Fusarium wilt. Mycopath (Pakistan).Javaid, I. A., A. Ghafoorm and R. Anwar. 2002. Evaluation of local and exotic pea Pisum sativum germplasm for vegetable and dry grain straits. Pak. J. Bot, 34: 419-427.Khan, I., S. Alam and A. Jabbar. 2002. Selection for resistance to Fusarium wilt and its relationship with phenols in chickpea.Khan, S. A., A. Awais, N. Javed, K. Javaid, A. Moosa, I. U. Haq, N. A. Khan, M. U. Chattha and A. Safdar. 2016. Screening of pea germplasm against Fusarium oxysporum f. sp. pisi and invitro management through chemicals. Pakistan Journal of Phytopathology, 28: 127-131.Khokhar, M. 2014. Production status of major vegetables in Pakistan, their problems and suggestions. Agric. Corner, 9.Kraft, J. M. 1994. Fusarium wilt of peas (a review). Agronomie, 14: 561-567.Maitlo, S., R. Syed, M. Rustamani, R. Khuhro and A. Lodhi. 2014. Comparative efficacy of different fungicides against fusarium wilt of chickpea (Cicer arietinum L.). Pakistan Journal of Botany, 46: 2305-2312.McPhee, K. 2003. Dry pea production and breeding. Food, Agri Environ, 1: 64-69.Nawab, N. N., G. M. Subhani, K. Mahmood, Q. Shakil and A. Saeed. 2008. Genetic variability, correlation and path analysis studies in garden pea (Pisum sativum L.). J. Agric. Res, 46: 333-340.Nene, Y., M. Haware and M. Reddy. 1981. Chickpea diseases: resistance-screening techniques.Pande, S., J. N. Rao and M. Sharma. 2007. Establishment of the Chickpea Wilt Pathogen Fusarium oxysporum f. sp. ciceris in the Soil through Seed Transmission. The Plant Pathology Journal, 23: 3-6.Persson, L., L. Bødker and M. Larsson-Wikström. 1997. Prevalence and pathogenicity of foot and root rot pathogens of pea in Southern Scandinavia. Plant Disease, 81: 171-174.Steel, R. G. D. and J. H. Torrie. 1980. Principles and procedures of statistics, a biometrical approach. 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Antioxidant defense system in chickpea against drought stress at pre- and post- flowering stages

Ten wilt resistant and three wilt susceptible chickpea genotypes were subjected to drought stress at pre and post flowering stages along with four drought tolerant and three drought susceptible checks by withholding irrigation. The three wilt resistant chickpea genotypes viz., GJG 0922, JG 24 and JG 2001-4 recorded significant increase in proline and glycine betaine accumulation and SOD, APX, GPX, CAT activities under water-deficit stress at preflowering stage. The mean leaf proline content of the control genotypes was 23.72 µmol g−1 DW and increased to 56.73 µmol g−1 DW under drought stress at preflowering stage. Based on the level of osmolyte accumulation, induction of antioxidative enzymes, five chickpea genotypes viz., JG 552476, GJG 0922, JG 24, JG 2001-4 and GJG 0919 could be categorized as drought tolerant. Chickpea genotype PBG 5 which recorded 26.8% wilt incidence and exhibited higher induction of antioxidative enzymes was rolerant to drought stress at preflowering stage while the three wilt resistant genotypes viz., BCP 2010-1, GJG 0904 and IPC 1048 appeared to be drought susceptible.

Induced defense dynamics in plant parts is requisite for resistance to Helicoverpa armigera (Hubner) infestation in chickpea

Helicoverpa armigera is the most serious insect pest in chickpea that causes significant yield losses due to its feeding on vegetative (leaves) and reproductive (developing pods and seeds) parts of plants. The present aim of study was to explore response dynamics of induced defence mechanism in leaves, podwall and seeds of ten chickpea genotypes (ICC 506, ICCV 10, ICC 10393, 5283, RSG 963, GL 25016, GL 26054, ICCL 86111, ICC 3137, L 550) after insect infestation. Two chickpea genotypes namely ICC 3137 and L 550 were found to be highly susceptible to Helicoverpa armigera infestation due to higher leaf and pod damage in them as compared to rest of eight genotypes which are found to be considerably resistant due to lower damage. Insect infestation induced decreased activities of defensive enzymes such as peroxidase (POD), catalase (CAT), glutatione reductase (GR) and polyphenol oxidase (PPO), decreased free radical scavenging activities in terms of 2,2-diphenyl-1-picryl hydrazyl (DPPH), decreased contents of signaling molecules such as nitric oxide ((NO), hydrogen peroxide (H2O2), reduced content of insect feeding behaviour regulating molecules such as total phenols, trypsin inhibitor and accumulation of membrane damage marker such as malondialdehyde (MDA) in leaves of ICC 3137 and L 550; decreased POD activity, nitric oxide content and H2O2 in podwall of L550; decreased SOD, GR, nitric oxide content and H2O2 in seeds of L550 resulted in aggravation of infestation induced oxidative stress and makes these genotypes more vulnerable to insect damage. The resistance of rest eight chickpea genotypes to insect infestation was due to the integrative effect of up regulated defensive components in leaves, podwall and seeds such as enhanced activities of CAT, POD, GR, PPO and PAL along with accumulation of H2O2` and total phenols in leaves, increased SOD, POD, GR and PPO activities along with increased contents of trypsin inhibitor and total phenols in podwall; increased SOD, GR, PPO activities and accumulated total phenols in seeds of resistant chickpea genotypes might be responsible for causing significant shift in oxidative status of these genotypes due to scavenging of free radicals, maintenance of membrane integrity and deterrent to insect feeding. Induced glycine betaine after herbivory was found to be positively correlated with superoxide dismutase and trypsin inhibitors. H2O2 content was positively correlated with trypsin inhibitor, DPPH, ferric reducing antioxidant power (FRAP) and total phenols in leaves and with FRAP, DPPH and total phenols in pod wall indicating that H2O2 might be stimulating the cascade that will be helping to scavenge free radical species and correlation with phenols and trypsin inhibitor indicated that it act as toxicant to insect feeding.

Antioxidants Potential in Seeds of Chickpea Genotypes Differing in Helicoverpa armigera Resistance

Seeds of fourteen chickpea genotypes (GL 25016, GL 26054, ICCL 86111, GL 28185, GL 29303, GL 28389, CE 1, CE 9, CE 35, GL 28390, PBG 5, GPF 2, GL 21107 and L 550) were evaluated for their stress tolerance capacity against Helicoverpa armigera. DPPH radical scavenging activity, glycine betaine, reducing power, total protein, trypsin inhibitor, H2O2 and proline was higher in seeds of resistant chickpea genotypes than the susceptible genotype (L550). MDA content was higher in susceptible genotype than the resistant genotypes. DPPH radical scavenging activity was negatively correlated with pod damage which shows higher free radical scavenging activity in resistant genotypes than susceptible genotype. Clustering of chickpea genotypes shows that resistant genotypes and moderately resistant genotypes form cluster with each other while susceptible genotypes do not form any cluster with any other genotype. SDS-PAGE results showed that content of higher molecular weight protein was higher in resistant genotypes than the susceptible genotype while low molecular weight protein was higher in susceptible genotypes than the resistant genotypes.

Evaluation of no-choice cage, detached leaf and diet incorporation assays to screen chickpeas for resistance to the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae)

It i.s difficult to compare genotypic resistance to insects across seasons and locations because of the variation in the onset and severity of insect infestation. Therefore, in this study, we used the no-choice cage technique and detached leaf and artificial diet incorporation assays for evaluating chickpea genotypes for resistance to the beet armyworm Spodopteraexigua (Hubner). The results indicated that the no-choice cage technique was not useful for evaluating chickpea genotypes for resistance to S. exigua. In the detached leaf assay, leaf feeding by S. exigua larvae was significantly lower in ICC 12 475 and RIL 20 genotypes at the vegetative stage and in ICC 10 393, ICC 12 475, KAK 2, RIL 20 and RIL 25 genotypes at the flowering stage, while larval weight gain was lower in insects reared on EC 583264, ICC 10 393, ICC 12 475 and RIL 20 genotypes at the vegetative stage; and in those reared on ICC 10 393, ICC 12 475, EC 583264, ICCL 86 111, KAK 2, RIL 20 and RIL 25 genotypes at the flowering stage in plants raised under greenhouse conditions. In plants raised under field conditions, the EC 583260, ICC 12 475, ICCL 86 111, ICCV 10, KAK 2, RIL 20 and RIL 25 genotypes in the November sowing and the KAK 2, ICC 3137, ICCL 86 111 and RIL 25 genotypes in the December sowing suffered low leaf damage at the vegetative stage; and EC 58 320, EC 583264, ICC 12 745 and RIL 25 genotypes in the November sowing and the EC 583264, ICC 3137, ICC 12 475, 1CCL 86 111, KAK 2, RIL 20 and RIL 25 genotypes in the December sowing suffered low leaf damage at the flowering stage, while low larval weights were recorded in insects reared on the ICC 12 475, EC 583264, ICCL 86 111 and RIL 25 genotypes at the flowering stage. In the diet incorporation assay, the survival of S. exigua larvae reared on diets with leaf powder of the ICC 12 475, ICC 10 393 and RIL 25 genotypes was significantly lower, while a significant reduction in larval weights was recorded in those reared on diets with leaf powder of the ICC 10 393, ICC 12 475, ICCL 86 111, KAK 2, RIL 25 and ICC 3137 genotypes. The fecundity of insects was also reduced in insects reared on diets with leaf powder of the RIL 25, RIL 20, ICCV 10, ICCL 86 111, ICC 12 475, ICC 3137, KAK 2 and ICC 10 393 genotypes. The results suggest that detached leaf assay could be used for large-scale screening of chickpea genotypes for resistance to S. exigua, while the diet incorporation assay could be used to gain additional information on the antibiosis mechanism of resistance to this insect.

English

This study observed resource of resistance in chickpea (Cicer arietinum L.) genotypes to its principal insect pest gram pod borer Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae). For this purpose, the susceptibility or resistance of 26 chickpea genotypes was checked at the farm conditions on the basis of combinations of different selected criteria (pod borer’s population, percentage of pod damage and grain yield). No any of protective measures were implemented to control insect pest spreading on crop. Data on numbers of H. armigera population per plant along with its damage were collected during seedling and pods formation stages, whereas, at crop maturity after harvesting determined seed yield to analyze statistically. Generally, pod borers infestations on different chickpea genotypes remained variable throughout cropping season. Similarly, grain yield of various genotypes also differed due to variable pest intensity and genetic diversity. Considering overall performance amongst the trial material, genotypes CM-24-2/02, CM-210/01, CH-53/99, and CC-94/99 proved the most stable for lessening pest population density and damage, and enhancing grain yield. This was almost certainly due to high potential of resistant chickpea genotypes for pest tolerance and yield enhancement; therefore, genotypes CM-24-2/02, CM-210/01, CH-53/99, and CC-94/99 may be used as resistant donors in the crossing program to evolve pod borer tolerant varieties of chickpea. On the other hand, genotype CM-86-3/02 appeared awkward because of highly affected in its survival against insect pest and poorest yield performance. Consequently, host plant resistance could be regarded as the most important sustainable approach to reduce losses due to insect pests. Key words: Cicer arietinum, resistance, Helicoverpa, pod borer, chickpea.

Development of screening techniques and identification of new sources of resistance to Ascochyta blight disease of chickpea

Effective controlled-environment and field screening techniques were developed and refined to identify resistance to Ascochyta blight (AB), caused by Ascochyta rabiei (Pass.) Labr. in chickpea. A controlled environment plant growth room facility developed for AB evaluation at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India was modified to evaluate chickpea genotypes for resistance to AB. Controlled environment screening techniques, such as a seedling screening technique using 10-day-old seedlings and cut-twig screening techniques using excised twigs (10–15 cm long) were developed. Components of the screening techniques were optimized in the controlled environment-plant growth room. The controlled environment screening techniques were found to be rapid, reliable and reproducible and a positive correlation was found between the seedling and cut-twig screening techniques (r = 0.94). The cut-twig screening technique was quicker than the seedling screening technique and is particularly useful in screening segregating breeding lines derived from wild Cicer spp. Results of the controlled environment screening techniques were compared with results of field screening trials carried out at Dhaulakuan and Ludhiana in India, where the pathogen is endemic. A significant positive correlation was found between results from the controlled environment and field screening techniques (r = 0.88). Using these resistance screening techniques, 150 elite chickpea breeding lines were evaluated and 29 lines with high and stable resistance to AB were identified.

Evaluating Chickpea Genotypes for Resistance to Ascochyta Blight in Nebraska

Ten irrigated or dryland chickpea field trials in the Nebraska Panhandle over the three year period (2005-2007) assessed parental genotypes and cultivars for disease resistance to Ascochyta blight caused by Aschochyta rabiei. The most promising genotypes for all aspects of disease resistance were the breeding lines PI 17256 and CA0090B347C. PI 17256 had significantly better disease ratings in two of the four dryland trials and five of the six irrigated trials compared to the three standard commercial cultivars (Dylan, Dwelley, and Sierra). Overall, breeding line CA0090B347C was intermediate between PI 17256 and the other entries in terms of disease resistance, with similar ratings to PI 17256 but better than the commercial cultivars in two of the four dryland trials and two of the six irrigated trials. PI 17256 produced the highest yields in three trials, while CA0090347C produced significantly higher yields than the commercial cultivars in three other trials. These two lines should be useful as germplasm sources for ongoing breeding efforts to develop new, adapted blight-tolerant cultivars for Nebraska. Accepted for publication 11 May 2009. Published 20 July 2009.