GENETIC-ANALYSIS OF RESISTANCE TO LEAF-RUST (PUCCINIA-RECONDITA F-SP TRITICI) PATHOTYPES IN THE DURUM WHEATS PBW-34 AND DWL-5023

Genetic analysis of leaf-rust resistance was conducted on two durum wheats. Triticum dui um cvs. 'PBW 34' and 'DWL 5023' were crossed with the leaf-rust-susceptible durum wheat 'Malvi Local'. The F-1, F-2 and F-3 generations were tested against leaf-rust pathotypes 1, 77A and 108. In 'PBW 34', a single dominant gene was effective against each of the pathotypes 1 and 108, whereas two independently inherited dominant genes were effective against pathotype 77A. In 'DWL 5023'. two independently inherited dominant genes were operative against pathotypes 1 and 77A, whereas a single dominant gene was identified as being operative against pathotype 108. Allelic tests on F-2 generation and joint segregation analysis on F-3 generation seedlings, suggested that two different genes in each cultivar are effective against these three leaf-rust pathotypes. Cultivar 'PBW 34' has Lrd1 and Lrd2 genes whereas Lrd1 and Lrd3 genes are present in 'DWL 5023'.