Induced Hybridization in Graminicolous Smut Fungi. III. Further Studies of Ustilago Hordei X U. bullata

Publisher Website
Google Scholar
Abstract
In a 2nd, more inclusive study, hybridization attempts were made with 83 select, highly compatible monosporidial combinations representing 1 collection of U. hordei (from Elymus canadensis) and 5 of U. bullata, E. canadensis, E. glaucus, and Agropyron caninum served predominantly as the common hosts. Seventy-four F1, 62 F2, 27 F3, and 19 F4 hybrids resulted. Lysis of promycelia or sporidia or both precluded use of pedigreed monosporidial lines of the hybrids as inoculum. Therefore, teliospores were used. Of the 19 interspecific hybrids carried through the F4, 3 are described in detail. The F1 spores were echinulate (as compared with smooth in the U. hordei parent, and verruculose in the U. bullata parent), mostly lighter-colored on 2 sides (U. hordei spores are lighter-colored on 1 side, wall uniformly pigmented in U. bullata), and intermediate in size. The F2 contained parental types and several unlike either parent. Some of the F3 and F4 segregates possessed characters not attributable phenotypically to either parent smooth spores notched on the lighter sides, echinulate spores with laminated exospore, smooth spores broadly indented on 1 side. Each of these is morphologically distinct from any described sp. of Ustilago on Gramineae and if encountered in nature would be seized upon as new sp. The predominance of intermediate types, the gradation of characters from 1 parental extreme to the other, and the evidence of heterosis suggest that the inheritance of most of the characters is governed by multiple factors.

This publication has 1 reference indexed in Scilit: