Evaluation of host-pathogen interaction of Mycovellosiella' Cajan with pigeonpea

Abstract

Although Mycovellosiella cajan is an important pathogen limiting production of pigeon pea through transmission of Mycovellosiella leafspot, little is known about the structural formation of either the host (pigeonpea) or the fungus. Thus, this study was conducted to assess any differences in structure as an indication of resistance in pigeonpea genotypes to Mycovellostella cajon. Germtube growth was not different in either of the pigeonpea germplasms assessed. Penetration in pigeonpea by Mycovellosiella cajan was inhibited by production of stomatal exudates in resistant varieties. In susceptible varieties germtube grew towards the stomata and penetrated either directly or through the stomata. In resistant varieties germtube bypassed the stomata and the point of penetration was not easily noticed. Mycovellosiella cajan sporulated in susceptible pigeon pea leaves 16 - 18 days after inoculation and in resistant varieties, conidiophores were not observed even after 16 days. In susceptible varieties there was rupturing of the stomata due to inass production of conidiophores through the stomata.