Abstract

A promising F₇ breeding population has been derived from the quackgrass [Elytrigia repens (L.) Nevski] ✕ bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Löve] hybrid after 20 years of selection. Field studies were conducted to determine the potential of making additional genetic advances in subsequent generations. Significant differences were found among 172 hybrid clonal lines and their open pollinated progenies for seed and forage yield and extent of rhizome development. Broad-sense heritabilities were 94, 40, and 87% for seed and forage yield and rhizome development, respectively. Phenotypicorrelations (r, 170 df) among parental and progeny means were 0.30 for seed yield and ranged from 0.38 to 0.50 for rhizome development. Positive responses to selection pressure to alter the degree of rhizome development in the hybrid population add credence to the relatively high heritability estimates obtained. True-breeding caespitose or rhizomatous strains have been developed after two cycles of selection. A hybridization program to broaden the genetic base of the breeding population has been initiated.

Copyright © . .