Root Rot Of Chickpea Research Articles

Identification of Fusarium spp. Associated with Chickpea Root Rot in Montana

Root rot caused by Fusarium spp. is a significant issue in the chickpea-growing regions of Montana. The specific Fusarium species responsible for the disease and their prevalence remain uncertain. A survey was conducted in 2020 and 2021 to identify Montana’s Fusarium species associated with chickpea. Four hundred and twenty-six Fusarium isolates were recovered from symptomatic chickpea roots across ten counties in the state. Isolates were identified by comparing translation elongation factor 1-α (TEF1-α) sequences in the FUSARIUM-ID database. Among the recovered isolates, Fusarium oxysporum was the most prevalent species (33%), followed by F. acuminatum (21%), F. avenaceum (15%), F. redolens (14%), F. culmorum (6%), F. sporotrichioides (6%), Neocosmospora solani (6%), F. equiseti (2%), F. torulosum (0.9%), F. gamsii (0.8%), F. proliferatum (0.2%), F. pseudograminearum (0.2%), and F. brachygibbosum (0.1%). The aggressiveness of a subset of 51 isolates representing various Fusarium spp. was tested on chickpea cv. ‘CDC Frontier’. A non-parametric variance analysis conducted on disease severity ranks indicated that F. avenaceum isolates were highly aggressive. This study reports for the first time that F. gamsii, F. proliferatum and F. brachygibbosum are causal agents of root rot in chickpea in the United States. This knowledge is invaluable for making informed decisions regarding crop rotation, disease management, and developing resistant chickpea varieties against economically significant Fusarium pathogens.

Studies on Different Host Range of Root Rot (Rhizoctonia solani Kühn) under Pot House

The pathogen, Rhizoctonia solani has a wide host range infecting crops. In order to find out the host range of R. solani causing root rot of fenugreek, 13 plant species were selected which are commonly found in fenugreek growing ecosystem. Root rot caused by Rhizoctonia solani has become an important constraint to the growers in Rajasthan. Rhizoctonia solani cause root rot in chick pea, chilli, coriander, fenugreek, cumin, wheat, barley, okra, field pea, tomato, fennel and cabbage but spinach was not infected. Out of these plants maximum disease incidence was observed in paan methi (Trigonella foenum-graecum) i.e., 57.82 per cent whereas, minimum 28.31 per cent disease incidence was observed in barley (Hordeum vulgare).

Bacillus valezensis: A New Plant Growth Promoting Rhizobacterium for Plant Growth Promotion and Inhibition of Rhizoctonia bataticola for the Management of Dry Root Rot of Chickpea

Background: Chickpea production is threatened by dry root rot disease in recent years. The disease is caused by soil borne fungus Rhizoctonia bataticola (Taub) Butler with its pycnidial stage Macrophomina phaseolina (Tassi) Goid. Bacillus spp. is a rod shaped and gram negative rhizobacterium which is predominant in the soil. Hence, considering the economic importance of disease, the present investigation was carried out to repress the pathogen by using indigenous Bacillus spp. strains related to antagonistic potential and plant growth promoting traits Methods: Thirty indigenous bacterial PGPR strains were isolated from healthy rhizospheric soil samples of chickpea and their antagonistic potential was studied. Later, the potential ones were examined for plant growth promoting traits. The promising strains were identified at molecular level 16S rDNA. Results: All thirty PGPR strains of rhizospharic Bacillus were potentiality antagonistic against R. bataticola and nine strains showed more than 50 per cent inhibition of the pathogen. Out of nine strains, four strains recorded more growth promoting traits and they were identified at molecular level as Bacillus cereus, Bacillus velezensis, Bacillus subtilis and Bacillus subtilis sub sp. Subtilis. Bacillus valezensis is a new report on rhizosphaeric PGPR against R. bataticola in chickpea.

Indigenous bacterial endophytic PGPMs of chickpea: Characterization and hidden antagonistic potential against <i>Rhizoctonia bataticola</i> causing dry root rot of chickpea

Chickpea (Cicer arietinum L.) is grown in more than 50 countries. India is the largest chickpea-producing country accounting for 64% of the global chickpea production. However, the production is contrained by the dry root rot disease caused by Rhizoctonia bataticola. Considering this problem, the investigation was carried out to isolate, characterize and the antagonistic potential of indigenous endophytic PGPMs for one of the components in the integrated management of dry root rot of chickpeas in eco-friendly manner. Hence, the isolation of thirty endophytic PGPMs was carried from chickpea by using the spread plate technique. The cultural characters and Gram’s staining reaction confirmed that the endophytic PGPMs isolated from chickpea plant tissues were bacteria. Among thirty bacterial strains, eight showed more than 50% of mycelial inhibition of the pathogen. Out of eight strains, five highly superior strains were selected and subjected for 16S rDNA gene sequencing using the universal primers (16Sr DNA F and 16Sr DNA R), which produced amplified products of size 1500 bp. nBLAST results of 16S rDNA gene sequence revealed that all the endophytic bacterial PGPMs showed homology with genus Bacillus but with different species. The five potential strains namely, BEPGPM-5, BEPGPM-9, BEPGPM-27, BEPGPM-28, and BEPGPM-30 were identified and confirmed as B. tropicus, B. pacificus, B. cereus, B. subtilis, respectively, based on molecular technique.

A novel blight and root rot of chickpea: A new host for Neoscytalidiumdimidiatum

In the southeastern province of Mardin in Turkey, a severe and novel fungal infection affected all chickpea plant parts, resulting in blight symptoms on stem, petiole, branch, and leaf, defoliation, seed and root rot, and death. Neoscytalidium dimidiatum was identified as the agent responsible for this new blight and root rot using sequence analysis of the ITS, tef1, and tub2 loci as well as morphological data. The pathogen was found in all surveyed districts and fields, with varying incidences of blight and root rot, blight being nearly twice (40%) as common as root rot (21%), and root-rotted and blighted plants co-occurring in the majority of instances. All 92 N. dimidiatum isolates from various tissues induced necrotic lesions on the inoculated plants, indicating they were pathogenic for chickpea. Conidia exhibited germination across a temperature range, with increasing temperatures positively influencing germination rates, and mycelial growth was significantly influenced by temperature, with the optimal growth temperature observed to be 35 °C. The response of 25 Turkish chickpea cultivars and three other genotypes when subjected to inoculation with Ciar 12 and Ciar 78 isolates, representative of phylogenetic clusters, was evaluated based on the severity of blight and root rot. The majority of cultivars and genotypes displayed high susceptibility and suffered mortality when exposed to either soil or spray inoculation with each isolate. Among the assessed cultivars and genotypes, Çağatay had the lowest severity of root rot. This study is the first to report a natural infection of chickpea plants by N. dimidiatum. Under global warming, this may be detrimental to chickpea cultivation and habitat in southeastern Turkey, which is the origin of chickpeas.

Identification of Resistant Genotypes and Integrated Management of Dry Root Rot of Chickpea

Background: Dry root rot is an economically important soil borne disease of chickpea in India. The pathogen, Rhizoctonia bataticola, is a soil borne fungus resulting in significant losses in yield. Therefore, the present investigation was aimed to identify the management strategy of disease through identification new sources of resistance and integrated management of disease. Methods: R. bataticola was isolated and purified by using hyphal tip technique and molecular detection was done by using ITS primers. One hundred chickpea germplasm entries were screened under in both field and advanced phenotyping in glass house. The field trials on integrated management of the disease were conducted with different treatments using randomized block design. Result: Fourteen resistant and five moderately resistant genotypes were identified under artificial epiphytotic conditions. Advanced screening of these 19 genotypes under phenotyping technique yielded four resistant and five moderately resistant genotypes. Among nine treatments, seed treatment with mancozeb 50% + carbendazim 25% WP @ 3.5 g/kg followed by soil drenching of mancozeb 50% + carbendazim 25% WP @ 3 g/l water to infected and surrounding plants was found highly effective by recording least disease incidence with highest seed yield, test weight and benefit cost ratio.

Screening of Different Bioagents and Fungicides against Dry Root Rot of Chickpea Incited by Macrophomina phaseolina (Tassi) Goid

Background: Dry root rot of chickpea caused by Macrophomina phaseolina (Tassi) Goid is a serious biotic constraint for chickpea production in Rajasthan. For the management of soil borne disease like dry root rot of chickpea, by using fungicides alone is not feasible due to environmental and health hazards. Hence integrated management of the disease by using bio-agents and fungicides is the best alternative. Therefore, in the present investigation, our main emphasis was to identify best fungicide and bio-agent for management of dry root rot in chickpea. Methods: Eight fungicides and four bio-agents were evaluated against dry root rot pathogen (M. phaseolina) in lab as well as in field condition. The experiment was conducted at instructional farm, COA, SKRAU, Bikaner during Rabi-2019 on most popular cv. GNG-1581 in RBD design with the application of seed treatment and soil application of different bio-agents and fungicides at different concentrations against dry root rot disease and compared with an untreated control. Result: Among all the fungicides used in the present investigation, tebuconazole 50% + trifloxystrobin 25% was found most effective in inhibiting the mycelial growth of the pathogen. Among all the bio-agents, T. harzianum was found most effective in inhibiting the mycelial growth of the pathogen. Under field condition, tebuconazole 50%+ trifloxystrobin 25% WG as seed treatment @ 1.5 g/kg along with T. harzianum @ 10 kg/ha as soil application gave maximum (83.76 %) disease control with highest pod yield (19.5 q/ha) and net return (Rs 39,826/ha). These treatments can provide an effective and economical management of dry root rot disease for chickpea cultivators.

In vitro evaluation of bioefficacy of novel fungal endophytes against Rhizoctonia bataticola (Taub).Butler causing dry root rot of chickpea

Dry root rot is an emerging disease posing threat to chickpea cultivation around the world. It is caused by the soilborne pathogen Rhizoctonia bataticola. The current study was conducted to investigate the potential of employing endophyticmicroorganisms that are antagonistic to R. bataticola to manage dry root rot. A total of 18 fungal endophytes were isolatedfrom healthy chickpea plant (stem and root). The isolated fungal endophytes were evaluated against R. bataticola by dualculture technique under In vitro conditions. Isolate IFRE 2 (Trichoderma yunnanense) exhibited the maximum inhibition ofpathogen growth, followed by BFRE 3 (Trichoderma simmonsii) and IFSE 2 (Trichoderma rifaii). The least mycelialinhibition was observed in BFRE 2 followed by IFSE 4. The effective endophytes were further evaluated for theirbioefficacy against dry root rot under glasshouse conditions as a component of integrated disease management

The chickpea root rot complex in Saskatchewan, Canada- detection of emerging pathogens and their relative pathogenicity.

Chickpea fields in Saskatchewan, one of the three Canadian prairie provinces, have suffered from major health issues since 2019, but no definitive cause has been determined. Field surveys were conducted in Saskatchewan in 2020 and 2021 in order to develop a better understanding of root rot pathogens associated with chickpea. Root samples were analyzed for the presence of 11 potential chickpea root rot pathogens using end-point PCR. Fusarium redolens, F. solani and F. avenaceum were the most prevalent pathogen species detected in both survey years. The cause of Fusarium wilt in chickpea, F. oxysporum f. sp. ciceris, was not detected in either year, nor were Phytophthora spp. and Verticillium albo-atrum. Berkeleyomyces sp. was detected in one field in each year, and Verticillium dahliae was detected in several fields sampled in 2021. These two pathogens have not been reported previously on chickpea in Saskatchewan. The prevalence of Fusarium species obtained from 2021 root isolations was similar to that determined by molecular tests, with frequent isolation of F. redolens, F. oxysporum, F. avenaceum and F. solani. A series of indoor pathogenicity testing compared root disease severity caused by a selection of 16 isolates of six Fusarium species and single isolates of V. dahliae, Berkeleyomyces sp. and Macrophomina phaseolina. Results showed that select isolates of F. avenaceum were the most aggressive of the Fusarium isolates on chickpea. Despite relatively low inoculum density, a highly aggressive isolate of F. avenaceum caused severe stunting and more root rot symptoms than single isolates of V. dahliae, Berkeleyomyces sp. and M. phaseolina under the test conditions.

Morpho-pathogenic and molecular diversity among Rhizoctonia bataticola isolates causing dry root rot of chickpea in Madhya Pradesh, India

Aim: The present study was conducted to identify the morphological, pathological and molecular variations in isolates of Rhizoctonia bataticola, causing dry root rot of chickpea collected from different parts of Madhya Pradesh, India. Methodology: The isolation, purification and identification of Rhizoctonia bataticola isolates was done from dry root rot infected chickpea plants, collected from 23 districts of Madhya Pradesh, India. Total 32 isolates of pathogen were obtained and further used for morphological, cultural, pathological and molecular characterization. The acquired data were subjected to DARwin5 software analysis for variability studies. The DNA isolates of the pathogen were also obtained and analysed to study molecular variability by RAPD analysis and the bands produced were subjected to PAST software for cluster analysis. Results: Thirty two isolates of R. bataticola with diverse origin showed a large variation in shape, size and initiation time of sclerotia. These isolates were pathogenic and grouped into three categories; highly virulent (59%), moderately virulent (25%) and less virulent (16%), under artificially inoculated conditions in sick soil method. The study of pathogenic variability revealed that ICC12441, ICC11332 and Pusa 212 were susceptible to all the isolates evaluated, whereas ICC12450, Pusa362, Pusa1103 showed moderate resistance against maximum isolates. Based on molecular characterization, the isolates were grouped into four clusters indicating that no two or more isolates were similar. Interpretation: The isolates of R. bataticola of chickpea from different agro-climatic zones of Madhya Pradesh, possess variability in their morphological and cultural characteristics, which not limited to geographical boundaries. The present study would be extremely useful for dry root rot management, as well as, in identifying donors for resistance breeding programmes. Key words: Chickpea, Diversity, Dry root rot, Pathogenicity, Rhizoctonia bataticola

Resistance screening and in-vitro efficacy of fungicides for the management of dry root rot of chickpea caused by Rhizoctonia bataticola

Dry root rot caused by Rhizoctonia bataticola (Taub.) Butler is an emerging threat for chickpea production. It is among one of the chief and common soil borne diseases of chickpea. The present investigation was conducted firstly to identify the resistant source for dry root rot in chickpea and secondly to evaluate the efficacy of different fungicides in inhibiting the growth of R. bataticola under in vitro conditions. Screening of a set of 50 chickpea entries resulted in identification of three entries namely ICCV 191317, ICCV 191306, and Ujjain 21 as moderately resistant to dry root rot of chickpea. No entry could be identified as completely resistant for dry root rot in chickpea. Further, among the different fungicides tested, pyraclostrobin alone and in combination of Thiophanate methyl completely checked the growth of R. bataticola at 100 ppm concentration under in vitro conditions. However, another combination product of fungicides namely carboxin + thiram and carbendazim + mancozeb also showed complete inhibition in growth of test pathogen at higher concentration of fungicides i.e. at 300 ppm concentration.The identified moderately resistant genotypes could be a useful resource for development of resistant varieties in chickpea for dry root rot using molecular breeding approaches.

Drought Stress Exacerbates Fungal Colonization and Endodermal Invasion and Dampens Defense Responses to Increase Dry Root Rot in Chickpea.

Drought plays a central role in increasing the incidence and severity of dry root rot (DRR) disease in chickpea. This is an economically devastating disease, compromising chickpea yields particularly severely in recent years due to erratic rainfall patterns. Macrophomina phaseolina (formerly Rhizoctonia bataticola) is the causal agent of DRR disease in the chickpea plant. The infection pattern in chickpea roots under well-watered conditions and drought stress are poorly understood at present. This study provides detailed disease symptomatology and the characteristics of DRR fungus at morphological and molecular levels. Using microscopy techniques, the infection pattern of DRR fungus in susceptible chickpea roots was investigated under well-watered and drought-stress conditions. Our observations suggested that drought stress intensifies the progression of already ongoing infection by weakening the endodermal barrier and overall defense. Transcriptomic analysis suggested that the plant's innate immune defense program is downregulated in infected roots when subjected to drought stress. Furthermore, genes involved in hormonal regulation are differentially expressed under drought stress. These findings provide hints in terms of potential chickpea genes to target in crop improvement programs to develop climate-change-resilient cultivars.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Aggressiveness of Phytophthora medicaginis on chickpea: Phenotyping method determines isolate ranking and host genotype‐by‐isolate interactions

AbstractPhytophthora medicaginis causing Phytophthora root rot of chickpea (Cicer arietinum) is an important disease, with genetic resistance using C. arietinum × Cicer echinospermum crosses as the main disease management strategy. We evaluated pathogenic variation in P. medicaginis populations with the aim of improving phenotyping methods for disease resistance. We addressed the question of individual isolate aggressiveness across four different seedling‐based phenotyping methods conducted in glasshouses and one field‐based phenotyping method. Our results revealed that a seedling media surface inoculation method used on a susceptible C. arietinum variety and a moderately resistant C. arietinum × C. echinospermum backcross detected the greatest variability in aggressiveness among 37 P. medicaginis isolates. Evaluations of different components of resistance, using our different phenotyping methods, revealed that differential pathogen–isolate reactions occur with some phenotyping methods. We found support for our hypotheses that the level of aggressiveness of P. medicaginis isolates depends on the phenotyping method, and that phenotyping methods interact with both isolate and host genotype reactions. Our cup‐based root inoculation method showed promise as a non‐field‐based phenotyping method, as it provided significant correlations with genotype–isolate rankings in the field experiment for a number of disease parameters.

Morphological, molecular and pathogenic characterization of Rhizoctonia bataticola isolates causing dry root rot of chickpea in Turkey

Nineteen chickpea isolates of R. bataticola were obtained from different locations of Turkey in 2016–2017. The isolates were examined for their morphology, genetic and virulence characteristics. The colony color of 10 isolates was grayish black and rest of them was black. Eleven isolates had appressed colony texture, while 3 isolates had velvety and 5 isolates had fluffy. Eight isolates produced aerial mycelium and the other did not. Eight isolates were categorized as fast growing, 8 isolates were categorized as medium growing and 3 isolates were categorized as slow growing. The mean sclerotial sizes of the isolates varied between 65.6 and 127.4 µm. The sclerotia of the 11 isolates were round, 3 isolates were ovoid and 5 isolates were irregular shaped. The size of the PCR products varied from 435 to 518bp and the isolates showed between 99.61 and 100% identity with the reference. The isolates were highly variable in their morphological, molecular and virulence characteristics.

Dry Root Rot of Chickpea: A Disease Favored by Drought.

Chickpea is an essential crop for protein nutrition and is grown around the world in rain-fed conditions. However, chickpea cultivation is under threat due to emerging diseases favored by drought stress. Dry root rot (DRR), an economically devastating disease, is an example. Chickpea-specific strains of a necrotic fungal phytopathogen, Macrophomina phaseolina, cause DRR. Microsclerotia of this fungus, which are capable of withstanding harsh environmental conditions, serve as primary inoculum. Initial symptoms are scattered necrotic spots in roots, progressing to rotting and withering lateral roots, accompanied by prematurely dried, straw-colored foliage. The recent rise in global temperature and worsening of drought spells have aggravated DRR outbreaks in chickpea. To date, DRR epidemiology has not been clarified in detail. Also, the literature lacks clarity on M. phaseolina taxonomy, morphology, disease progression, and diagnosis. In this article, research progress on patterns of DRR occurrence in the field and belowground and aboveground symptoms are clarified. In addition, the current understanding of taxonomy and management practices is elaborated. We also summarize knowledge of the impact of drought and high temperature on DRR severity. Furthermore, we provide future perspectives on the importance of host resistance, quantitative trait loci identification, and genotype screening for the identification of resistant genotypes. The article proposes new research priorities and a corresponding plan for the mitigation of DRR.

Evaluation of fungicides, plant extracts and bio-agents against dry root rot of chickpea (Cicer arietinum)

Dry root rot (DRR) of chickpea caused by Macrophomina phaseolina is an important disease affecting chickpea production especially in tropical and sub-tropical ecologies of world. The present investigation was planned to evaluate the in vitro efficacy of various fungicides, plant extracts and bio-control agents against Macrophomina phaseolina. Results suggested that among fungicides, significantly maximum mean mycelium growth inhibition was recorded with Carbendazim (100%) followed by Carbendazim+Mancozeb (84.65%). Likewise, among phyto extracts, garlic extract was excellent with maximum mycelia growth inhibition (70.15 and 100 %) followed by neem extract (68.35 and 82.35%) at 5 and 10% concentration, respectively. Among bio-agents, Trichoderma viride showed significantly maximum mycelia growth inhibition (80.20%) followed by Trichoderma harzianum (65.10%). Therefore, from the findings of present study, it can be concluded that apart from use of fungicides (Carbendazim and Carbendazim+Mancozeb) phyto extracts such as extract of garlic and neem leaves and bio-control agent Trichoderma viride can also be used as an effective alternative for management of DRR in chickpea. Findings of our study may help in development of sustainable management strategies against DRR thus minimizing its yield consequences in chickpea. However, there is a need to further strengthen the investigations on this aspect based on thorough understanding of the biology of the pathogen and host×plant×environment interaction especially under field conditions.

First report of Fusarium falciforme (FSSC 3+4) causing root rot on chickpea in Mexico.

Chickpea (Cicer aretinium L.) is a legume crop of great importance worldwide. In January 2019, wilting symptoms on chickpea (stunted grow, withered leaves, root rot and wilted plants) were observed in three fields of Culiacan Sinaloa Mexico, with an incidence of 3 to 5%. To identify the cause, eighty symptomatic chickpea plants were sampled. Tissue from roots was plated on potato dextrose agar (PDA) medium. Typical Fusarium spp. colonies were obtained from all root samples. Ten pure cultures were obtained by single-spore culturing (Ff01 to Ff10). On PDA the colonies were abundant with white aerial mycelium, hyphae were branched and septae and light purple pigmentation was observed in the center of old cultures (Leslie and Summerell 2006). From 10-day-old cultures grown on carnation leaf agar medium, macroconidias were falciform, hyaline, with slightly curved apexes, three to five septate, with well-developed foot cells and blunt apical cells, and measured 26.6 to 45.8 × 2.2 to 7.0 μm (n = 40). The microconidia (n = 40) were hyaline, one to two celled, produced in false heads that measured 7.4 to 20.1 (average 13.7) μm × 2.4 to 8.9 (average 5.3) μm (n = 40) at the tips of long monophialides, and were oval or reniform, with apexes rounded, 8.3 to 12.1 × 1.6 to 4.7 μm; chlamydospores were not evident. These characteristics fit those of the Fusarium solani (Mart.) Sacc. species complex, FSSC (Summerell et al. 2003). The internal transcribed spacer and the translation elongation factor 1 alpha (EF1-α) genes (O'Donnell et al. 1998) were amplified by polymerase chain reaction and sequenced from the isolate Ff02 and Ff08 (GenBank accession nos. KJ501093 and MN082369). Maximum likelihood analysis was carried out using the EF1-α sequences (KJ501093 and MN082369) from the Ff02 and Ff08 isolates and other species from the Fusarium solani species complex (FSSC). Phylogenetic analysis revealed the isolate most closely related with F. falciforme (100% bootstrap). For pathogenicity testing, a conidial suspension (1x106 conidia/ml) was prepared by harvesting spores from 10-days-old cultures on PDA. Twenty 2-week-old chickpea seedlings from two cultivars (P-2245 and WR-315) were inoculated by dipping roots into the conidial suspension for 20 min. The inoculated plants were transplanted into a 50-hole plastic tray containing sterilized soil and maintained in a growth chamber at 25°C, with a relative humidity of >80% and a 12-h/12-h light/dark cycle. After 8 days, the first root rot symptoms were observed on inoculating seedlings and the infected plants eventually died within 3 to 4 weeks after inoculation. No symptoms were observed plants inoculated with sterilized distilled water. The fungus was reisolated from symptomatic tissues of inoculated plants and was identified by sequencing the partial EF1-α gene again and was identified as F. falciforme (FSSC 3 + 4) (O'Donnell et al. 2008) based on its morphological characteristics, genetic analysis, and pathogenicity test, fulfilling Koch's postulates. The molecular identification was confirmed via BLAST on the FusariumID and Fusarium MLST databases. Although FSSC has been previously reported causing root rot in chickpea in USA, Chile, Spain, Cuba, Iran, Poland, Israel, Pakistan and Brazil, to our knowledge this is the first report of root rot in chickpea caused by F. falciforme in Mexico. This is important for chickpea producers and chickpea breeding programs.

Effect of Abiotic Factors on the Incidence of Dry Root Rot in Chickpea (Cicer arietinum L.)

An investigation was conducted on chickpea (Cicer arietinum L.) genotype JG-62 to study the effect of different abiotic factors on the incidence of dry root rot. Maximum disease incidence was observed at 35°C temperature while minimum disease incidence was observed at 20°C. More disease incidence was observed at low moisture conditions while low at high moisture conditions. Soil pH also influenced the disease incidence. Maximum disease incidence was observed at pH 4.5 while minimum disease incidence was observed at pH 7.5. The results are useful for managing the incidence of dry root rot in chickpea.

Invitro mycoparasitism activity of Trichoderma spp against Fusarium solani inciting root rot of chickpea ( Cicer arietinum L.)

Root rot of chickpea (Cicer arietinum L.) is caused by Fusarium solani. This paper describes the efficacy of Trichoderma spp. against sensitive and resistant isolates of F, solani by dual culture method under invitro conditions. Trichoderma virens, T. atroviride, T. viride, T. harzianum, T. koningiopsis, T. stilbohypoxyli,and T. pseudokoningii species were used for the antagonistic study. Results indicate that all Trichoderma species showed great antagonistic activity. But among them, T. virens, T. atroviride, T. viride showed 90% and 80 % antagonistic activity than others in case of a sensitive isolate of test fungus. The resistant isolate of the pathogen was restricting the antagonism to some extent.

Occurrence and Distribution of Dry Root Rot of Chickpea Caused by Macrophomina phaseolina (Tassi) Goid. in Arid Region of Rajasthan

Background: Dry root rot of chickpea caused by Macrophomina phaseolina (Tassi) Goid. is emerging as a serious threat to the chickpea production worldwide. The disease is gaining importance under the changing scenario of climate particularly in the rainfed ecologies of India and in arid and semi-arid region of Rajasthan. The current study was aimed to discusses current status of the disease and role of different factors in disease development to help in searching of possible management options for researchers to alleviate the problem. Methods: A roving survey was conducted to record the occurrence and distribution of dry root rot in ten major chickpea growing districts of Rajasthan during Rabi season 2014-15 and 2015-16. In each district, minimum three locations/villages were selected, in each location/village minimum three fields were selected and the incidence of disease was recorded after counting the diseased and healthy plants. Result: Overall range of disease incidence in all the districts vary from 5.75 to 12.51 per cent with an average of 9.15 per cent in Rajasthan. The maximum disease incidence 12.51 per cent was observed in Jaisalmer district while minimum in Ajmer district. The disease was found very common in sandy and sandy loam soil than any other types of soil. The deshi/local varieties were found to be more susceptible to infection of M. phaseolina as compared to improved varieties. Disease incidence was also observed higher in sprinkler system of irrigation as compared to flood method and rainfed conditions. The maximum disease incidence was observed in plants at flowering and podding stages in the months of February and March.