ARS | Publication request: INTER- AND INTRANATIONAL SPREAD OF ASCOCHYTA PATHOGENS OF CHICKPEA, FABA BEAN AND LENTIL

Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 1996
Publication Date: N/A

Interpretive Summary: The ascochyta blights of chickpea, faba bean and lentil, incited by Ascochyta rabiei, A. fabae and A. fabae f. sp. lentis, are important seedborne pathogens in many countries. Infected seed is important in the long-distance spread and survival of these three fungal pathogens. In the last 20-25 years, there has been a steady increase in the exchange of germplasm of these crops between countries. Seed transmission has been responsible for the introduction of the ascochyta blight pathogens of chickpea, faba bean and lentil into, and dissemination within, many countries worldwide. The sexual states of the blight pathogens of chickpea, faba bean and lentil belong to the genius Didymella. These fungi require the pairing of two compatible isolates (mating types) for successful sexual reproduction. Movement of infected seed of these three crops not only leads to the introduction of virulent forms of these fungi, but may lead to the distribution of compatible mating types, thus allowing the development of the sexual state and maybe even more races of the fungi. Storage of chickpea, faba bean and lentil seed at temperatures of 4 to -18 C in germplasm repositories not only prolongs the longevity of the seed, but also of associated seedborne ascochyta pathogens.

Technical Abstract: Ascochyta blights of chickpea, faba bean and lentil are caused by Ascochyta rabiei, A. fabae and A. fabae f. sp. lentis, respectively, all of which are important seedborne pathogens. Infected seed is important in the long distance spread and survival of these pathogens. In the last 20-25 years, there has been a steady increase in the exchange of germplasm of cool season food legumes between countries. Seed transmission has been responsible for the introduction of the ascochyta blight pathogens of chickpea, faba bean and lentil into, and dissemination within, many countries worldwide. The teleomorphic (sexual) states of the blight pathogens of chickpea, faba bean and lentil belong to the genus Didymella. These fungi are heterothallic, requiring the pairing of two compatible mating types for successful sexual reproduction. Movement of infected seed of these three crops not only leads to the introduction of virulent pathotypes, but may lead to the distribution of compatible mating types, thus allowing the development of the teleomorph in nature. Storage of chickpea, faba bean and lentil seed at temperatures of 4 to -18 deg C in germplasm repositories not only prolongs the longevity of the seed but also of the associated seedborne ascochyta pathogens.