Document Type : Original Article


1 Genet. Dept., Fac. Agric., Zagazig Univ., Egypt

2 Pl. Pathol. Dept., Fac. Agric., Zagazig Univ., Egypt


The present study aimed to investigate the genetic behavior of leaf rust resistance in bread wheat (Triticum aestivum L.), in a population of five parents and ten F1 hybrids under field conditions with artificial inoculation. Wide variations among parents and their F1 hybrids were detected for the five characters under study, i.e. incubation period (IP), disease severity (DS), infection response (IR), average co infection (ACI) and area under disease progress curve (AUDPC). The average means of criteria related to resistant varieties showed that Giza 168 and Sakha 93 wheat cultivars have good response for resistance as long time of incubation period, as well as little amount of disease severity, the same performance of both varieties for infection response, average co infection and AUDPC= D [1/2 (Y1 + Yk) + (Y2 + Y3 + …….. Yk-1)] criteria. The behaviour of F1's for studied criteria appeared to be different among and within five criteria. Gemmiza 11 × Giza 168 possessed complete dominance of long period, high (DS) and (ACI). In contrast, it was low value of AUDPC. The analysis of variance for five criteria were recorded highly significant differences among parents and their hybrids. The regression of (Wr/Vr) was insignificantly different from unity for all criteria except disease severity (DS). Significant differences of H1 and H2 estimates were obtained for incubation period (IP), disease severity (DS) criteria. While, AUDPC criteria possessed significant differences of D estimate. Mean degree of dominance (H1/D)1/2 indicated the presence of over dominance for all studied criteria. The proportion of genes with positive and negative effects in the parents (H2/4H1) indicated un equal frequances of positive and negative among the parents for DS and AUDPC criteria, except IP possessed nearly equal positive and negative gene among the parents. F1 graphic analysis revealed that cultivars G.168 and Sakha 93 had most dominant genes for resistance but cultivars Gemmiza 11 and Gemmiza 9 had most recessive genes for susceptibility. Bulked Segrigant Analysis were used by eight ISSR primers, the results confirmed the importance of Giza 168 may be as doner of resistant gene's, as well as Gemmiza 9. These confirmed the importance of Giza 168 considered as in late genotypes for using it to transport leaf rust resistant genes to other genotypes, Gemmiza 9 followed Giza 168 in the importance of leaf rust resistance, these results confirmed also the susciptability of Gemmiza 11 variety for leaf rust disease in bread wheat.