Genetic characterization of resistance to brown leaf spot caused by Drechslera oryzae in some wild rice (Oryza sativa) lines

Abstract

Sources of resistance against Dreschlem or).:ae (Breda de Haan) Subram. and Jain (syn. Heb~i~?thosporirroant zne, Bipolaris otyne) causing brown leaf spot disease severely affecting both quality and yield in the cultivated rice 01y:a sarivn L. (AA genome ) are rare. Hence 4 wild rice lines, namely 'CR 100117', 'CR 100140', 'CR 100142' and 'CR 100142 A' belonging to Oryza nivarn Sharma et Shastry (AA genome) consistently resistant to brown leaf spot in Ludhiana (Punjab) were genetically characterized under artificial epiphytotic conditions in the field. Analysis of brown leaf spot reaction of different segregating populations of the crosses of 2 susceptible commercial 0, sntiva cultivars 'PR 114' and 'Pusa 44' with the above 4 0. nivara revealed quantitative nature of inheritance of this trait. Additive, dominant as well as epistatic gene interactions were observed. Both fixable and non-fixable gene effects were important for the expression of brown leaf spot resistance. For the development of rice cultivars with durable resistance to brown leaf spot, the marker assisted selection (MAS) for the accumulation of polygenes is suggested.