Genetics of leaf rust resistence (Puccinia triticina E.) in elite durum wheat lines

Crosses between susceptible x resistant and resistant x resistant genotypes were carried out. the genetic resistance in three durum wheat (Triticum turgidum var. durum) genotypes resistant to BBG/BN leaf rust strain (Puccinia triticina E.), 'Atil C2000' was used as a susceptible genotype. The segregation of the F-3 generation indicated that 'Syria 1740' and 'CMH82A.1062' resistant genotypes possess two complementary dominant genes (a ratio of one resistant family to eight segregant families to seven susceptible families). The segregation of one resistant family (1:2:1) to two segregant families to one susceptible family in the 'Creso' cultivar indicated that the resistance was conferred by a single dominant gene. In the resistant x resistant 'Syria 1740 x Creso' and 'Creso x CMH82A.1062' crosses, the proportions of each one fit the phenotypic ratio of 63:1 thus indicating that the resistance was conditioned by three independent dominant genes in both cases. It was concluded that the genes of both parents segregated independently in each cross. In the 'Syria 1740 x CNIH82A.10621 cross, susceptible homozygous families were not observed in the field. When 'Syria 1740' and 'CMH82A.1062' were crossed with 'Atil C20001, both xhibited two dominant complementary genes that conditioned the resistance, the lack of susceptible families in this cross suggested that the resistance genes carried by both progenitors are the same.