Pleiotropic association of infection frequency and latent period of two barley cultivars partially resistant to barley leaf rust

Abstract

‘Cebada Capa’, carrying four to six minor genes for a longer latent period (LP), was crossed to ‘L94’ and ‘Vada’, carrying no and five to six minor genes for a longer LP respectively. Of each of 68 F3-lines the infection frequency (IF) and the LP of ten ‘just-heading’ plants were assessed. There appeared to be a strong association between IF and LP, whereby the relationship between IF and LP of both crosses could be described by a single linear regression equation. The data strongly suggest that the genes for increased LP pleiotropically decrease the IF. The possibility of a close linkage between genes for reduced IF and genes for increased LP, although unlikely, could not be excluded.