Varietal reaction and genetic resistance of subterranean clover (Trifolium subterraneum L.) to subterranean clover stunt virus infection

Abstract

Resistance to subterranean clover stunt virus was explored in 390 strains and named varieties of subterranean clover from the Mediterranean regions, England, France, the Iberian peninsula, New Zealand, and Australia. High levels of genetic resistance were shown in the Australian varieties Tallarook, Hill's Small, and Bass B. Resistance of a selected group of F2's was found to be midway between that of the parents. In selected groups of F4 generation hybrids, and in selected second and third generation backcrosses, resistance equal to that of Tallarook was shown. The apparent recovery of some plants during tests in the glass-house was shown to be a form of temporary tolerance to the virus.