تجزيه دي آلل تيپ آلودگي در زنگ زردگندم

Diallel Analysis of Infection Type in Wheat Stripe Rust

Genetic control of infection type of stripe rust was studied in a half-diallel design using six wheat varieties, Tiritea (a susceptible control), Tancred, Kotare, Otane, Karama, and Briscard. These varieties and their 15 Fi diallel hybrids were evaluated by three stripe rust pathotypes, 7E18A^-, 38E0A^+, and 134E134A+. For each pathotype a randomized complete block design was conducted with 21 treatments. Data for infection type were analyzed on the basis of Morley Jones, Walter and Morton, Griffing, and Haymanʹs graphical methods. Positive and negative degrees of dominance were observed for every pathotype, indicating the host-pathogen interaction. Analyses of variance showed the importance of both additive and dominance genetic effects in controlling the infection type of stripe rust. However, the role of additive effects was more important than non-additive effects. Average of broad-sense and narrow-sense heritability estimates were 0.92 and 0.89 , respectively. In the graphical analysis of Hayman, degree of dominance ranged from partial dominance to overdominance depending on the pathotype. Briscard, in all pathotypes, Karama in 7E18A^- and 38EOA^+ and Kotare in 134E134A^+, had mainly recessive genes. Significant negative general combining abilities (more resistance) were also obtained for Kotare in 7E 18A^-, for Briscard in 38E0A^+, and for Briscard, Karama, and Kotare in 134E134A^+. In conclusion, regarding the high heritability of infection type, it is possible to use the above mentioned varieties in breeding programs in order to reduce the infection type of stripe rust in wheat.