MODE OF POLLINATION OF PERENNIAL SPECIES OF THE TRITICEAE IN RELATION TO GENOMICALLY DEFINED GENERA

Abstract

The perennial grasses of the tribe Triticeae are among the world’s most valuable forages and provide an important gene source for wheat, barley, and rye breeders. Knowledge of mode of pollination (self-pollination versus cross-pollination) is essential to plant breeders, geneticists, and systematists involved in gene manipulation, germplasm preservation, and understanding the biological characteristics of taxa and their relatives. This paper reports for the first time on the mode of pollination of many perennial Triticeae grasses and evaluates the mode of pollination as it relates to the genomically defined genera of Dewey (1984). Self fertility was estimated by counting seed set on spikes that were enclosed in an isolation paper bag prior to anthesis to exclude foreign pollen. The latter genera can be grouped as follows: (1) those that are highly self-sterile, which include Agropyron, Psathyrostachys, Pseudoroegneria, and Elytrigia, averaging 1.2 selfed seeds per spike; (2) those variable in their degree of self-fertility, Thinopyrum, Leymus, and Pascopyrum, ranging from 0.0 to 46.1, 0.0 to 254.0, and 0.0 to 67.8 selfed seeds per spike, respectively; and (3) those genera highly self-fertile which include Elymus and Critesion, that average more than 30 self-seeds per spike. Taxa in group two show considerable variation within species as well as between species. In group three, the E. lanceolatus, C. brevisubulatum, and C. bulbosum complex are exceptions; their component taxa were highly self-sterile.Key words: Pollination, reproduction, Triticeae, genomes