Studies on resistance of pea to pea seed borne mosaic virus and new pathotypes

Abstract

Studies were carried out to search for virulent pathotypes of pea seed borne mosaic virus (PSbMV) on pea and to explore new sources of resistance in French and Indian pea collections. A virulent pathotype, PSbMV-Pi, capable of partially overcoming the recessively resistant gene sbm 1, was identified for the first time in an Indian pea line. PSbMV-Pi did not produce visible symptoms on sbm 1 lines, on which it had a reduced multiplication and could no longer be detected by ELISA seven wk after inoculation. However, it multiplied normally on the susceptible cultivars and could be differentiated from other strains on a set of strain differentials. Also, another strain, PSbMV-Pv, of the virulent pathotype, that appeared to multiply slightly better than PSbMV-Pi on sbm 1 lines, was recovered from the local strain of PSbMV.Five new sources of resistance to PSbMV were screened from the Indian pea collection by a rapid screening based on the assumption that, in germplasm collections, the virus is generalised to all susceptible lines by aphid vectors. The initial step of testing a few testas of each germplasm line in ELISA and the rejection of positive lines eliminated 85% of the germplasm before further testing in the field. The inheritance studies on four of the five resistant lines lead to reidentification of the sbm 1 gene. The sbm 1 lines behaved fairly well under heavy inoculum pressure in the pea fields in 1989.

Achievements and Challenges in Legume Breeding for Pest and Disease Resistance

“…Resistance to pea seed-borne mosaic virus has been reported in pea and several recessive resistance genes have been identified (Hagedorn and Gritton, 1973;Khetarpal et al, 1990). Molecular markers associated with the resistance gene are now available (Gao et al, 2004).…”

Current status and future strategy in breeding pea to improve resistance to biotic and abiotic stresses

“…They designated the gene as sbm. Certain new pathotypes of PSbMV were discovered on the basis of differential reactions on pea genotypes (Khetarpal et al ., 1990) . Studies on inheritance of resistance to the new pathotypes led to the identification of four separate, recessive genes which govern resistance .…”

“…Studies on inheritance of resistance to the new pathotypes led to the identification of four separate, recessive genes which govern resistance . New symbols have been proposed including sbml (earlier known as sbm), sbm2, sbm3 and sbm4 (Khetarpal et al ., 1990) . Only sbml located in the Pisum linkage group 6 (Hagedorn & Gritton, 1973) has so far not been overcome by any pathotype of PSbMV.…”

“…Other sources of resistance to PSbMV include : X78123, X78126 and X78127 which are known to carry sbml (Khetarpal et al ., 1990), and PLP40, PLP350, EC15184, EC17451 and PLP564 (Khetarpal et al ., 1990) . Seven breeding lines, OSU-547-29, OSU-559-6, OSU-564-3, OSU-584-16, OSU-589-12, OSU-615-15 and OSU-620-1, resistant to PSbMV and pea enation mosaic virus (PEMV) were released in 1988 (Baggett & Kean, 1988) .…”