Seedborne infection ofAscochyta rabiei in chickpea and its transmission to aerial plant parts

Dey, S. K.; Singh, Gurdip

doi:10.1007/bf03158589

Cited by 24 publications

(16 citation statements)

References 4 publications

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“…Ascochyta lentis was found in 36% of testae and cotelydons from seeds with more than 12% seed discolouration (Morrall and Beauchamp 1988). The mode of transmission from seed to the foliar plant parts was described as non-systemic (Dey and Singh 1994).…”

Section: Seedsmentioning

confidence: 99%

Comparison of the epidemiology of ascochyta blights on grain legumes

2007

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Asochyta blights of grain legumes are caused by fungal pathogens in the genus Ascochyta. Different species infect the different legume species, and in pea three species including Phoma medicaginis var. pinodella have been implicated in ascochyta blight. The impact of the diseases varies between crops, countries, seasons and cropping systems, and yield loss data collected under welldefined conditions is scarce. However, ascochyta blights are considered major diseases in many areas where legumes are grown. Symptoms appear on all aerial parts of the plant, and lesions are similar for most of the species, except for M. pinodes and P. medicaginis var. pinodella. Infected seed, stubble and/or air-borne ascospores are major sources of primary inoculum. Their importance varies between species and also between regions. All Ascochyta spp. produce rain-splashed conidia during the cropping season which are responsible for the spread of the disease within the crop canopy. Only in pea are ascospores involved in secondary disease spread. Limited data suggests that Ascochyta spp. may be hemibiotrophs; however, toxins characteristic for necrotrophs have been isolated from some of the species. Modelling of ascochyta blights is still in the developmental stage and implementation of such models for disease forecasting is the exception.

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Section: Seedsmentioning

confidence: 99%

Comparison of the epidemiology of ascochyta blights on grain legumes

2007

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“…Generally, seed transmission of related diseases on pulse crops is infrequent, in the order of a few seeds in a thousand (Gossen & Morrall, 1986), but the frequency of transmission is positively correlated with the proportion of infected seeds sown (Kimber, Scott, & Ramsey, 2006). The spread of the pathogen from infected seed to seedlings, referred to here as transmission, is non-systemic, in that contact must be made between the emerging growing point and lesions on the seed coat or cotyledons (Dey & Singh, 1994). As pycnidiospores are disseminated short distances by rain-splash, primary infections that originate from infected seedlings occasionally result in distinct foci randomly scattered about the field; plants in the centre of each focus are more severely diseased than those at its margins.…”

Section: Introductionmentioning

confidence: 98%

The role of seedling infection in epiphytotics of ascochyta blight on chickpea

Kimber

Shtienberg

Ramsey³

et al. 2006

Eur J Plant Pathol

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Didymella rabiei, the causal agent of ascochyta blight, survives on infected seeds and seedlings. Diseased seedlings originating from infected seeds occasionally serve as the source for primary infection in chickpea crops. Experiments carried out independently in Australia and in Israel provided quantitative information on the temporal and spatial distribution of ascochyta blight from initial infections and on the relationship between the amount of initial infection and the intensity of subsequent epiphytotics for cultivars differing in susceptibility to the pathogen. Disease spread over short distances (<10 m) from individual primary infections, was governed by rain and wind, and was up to five times greater down-wind than up-wind. Cultivar response to D. rabiei significantly affected the distance and area over which disease spread and the intensity of the disease on infected plants. At onset of the epiphytotic, the relationship between disease spread and time was exponential (P < 0.05; R 2 > 0.95) and the area of the resulting foci was over 10 times greater in susceptible cultivars than in resistant cultivars. Regression equations showed the relationship between disease severity and the distance from the focus-plants was inverse-linear for all cultivars tested (P < 0.05). A simulation model based on the experimental data revealed that even if primary infection is infrequent (less than 1% of plants), the consequences are potentially devastating when susceptible cultivars are used. The epidemiological information and simulation model generated by this study provide an increased understanding of the development of an epiphytotic in which the primary foci of disease originate from infected chickpea seedlings.

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“…Transmission from infected seed provides an early onset for disease introduction, creating a substantial time, beginning soon after plant emergence, for development of an epiphytotic. Seed to seedling transmission depends largely on the type of seed infection (Maden et al, 1975;Dey and Singh, 1994). Our experiments examining the role of host susceptibility on seed inoculation showed that 100% of AI seed was infected with D. rabiei, and the fungus had penetrated into the seed coat, as shown by high seed infection levels after surface-sterilisation.…”

Section: Discussionmentioning

confidence: 90%

“…Spread of ascochyta blight to seedlings from infected seed, referred to in this paper as transmission, is non-systemic, in that contact must be made between the emerging plant and lesions on the seed coat or cotyledons (Dey and Singh, 1994). In some instances, the frequency of seed transmission can be very low; less than one seed in a thousand (Gossen and Morrall, 1986).…”

Section: Introductionmentioning

confidence: 98%

Factors Influencing Transmission of Didymella rabiei (Ascochyta Blight) from Inoculated Seed of Chickpea Under Controlled Conditions

Kimber

Scott

Ramsey³

2006

Eur J Plant Pathol

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Ascochyta blight of chickpea (Cicer arietinum), caused by the fungus Didymella rabiei, has the potential to cause 100% crop loss in severe epiphytotics. Management of this disease often involves reducing sources of inoculum. The influence of sowing depth, host resistance, seed infection level and soil temperature on disease transmission was investigated in a series of glasshouse and growth room trials using seed artificially inoculated with D. rabiei. A positive correlation (R 2 =0.9992) was observed between rate of seed infection and the incidence of disease on seedlings. Disease transmission to seedlings was not significantly influenced by sowing depth (1, 3 and 6 cm) in separate trials on two cultivars. Susceptibility of the host showed no obvious influence on the frequency of disease transmission in two trials conducted using four cultivars ranging from highly susceptible to moderately susceptible/moderately resistant. Trials conducted in controlled conditions showed that there was no obvious relationship between soil temperature (5, 9, 14 and 19°C) and the incidence of disease on seedlings.

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Seedborne infection ofAscochyta rabiei in chickpea and its transmission to aerial plant parts

Cited by 24 publications

References 4 publications

Comparison of the epidemiology of ascochyta blights on grain legumes

Comparison of the epidemiology of ascochyta blights on grain legumes

The role of seedling infection in epiphytotics of ascochyta blight on chickpea

Factors Influencing Transmission of Didymella rabiei (Ascochyta Blight) from Inoculated Seed of Chickpea Under Controlled Conditions

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