Evaluation of tuber-bearingSolanum species for symptomology, as diagnostic hosts, and sources of immunityto potato virus Y necrotic strain (PVYN)

Abstract

A total of 258 Plant Introductions (PI) belonging to 69Solarium species were evaluated in the greenhouse for their reaction to the tobacco veinal necrosis strain of potato virus Y (PVY N). One hundred and thirty-one (50.7%) of the PI accessions produced mosaic symptoms ranging from mild to severe. Local lesion and veinal necrosis symptoms were observed in 19 PI accessions (7.3%) and a variety of other symptoms were observed in another 11 PI accessions (4.2%). Only 97 PI accessions (37.5%) were symptomless carriers of PVYN. PI accession 473505 ofS. sparsipilum and PI accession 498021 ofS. brachycarpum developed local lesions and veinal necrosis with PVYN, but necrotic spots and mosaic with PVYo. Common mechanically-transmitted potato viruses A, S, M, and X did not interfere with PVY symptom development inS. sparsipilum andS. brachycarpum. Thus, PI 473505 and PI 498021 can be used as indicator plants for specific identification of PVYN. PI accession 472819 ofS. chacoense developed local lesions with systemic spread in PVYo, but without systemic spread in PVYN. Thus, this can be used as a differential host plant for PVY strains. Two PI accessions ofS. stoloniferum, PI 160372 and 161171 were immune to PVYN.