Examination of Pisum and Lathyrus species as sources of ascochyta blight resistance for field pea (Pisum sativum)

Ascochyta blight resistance in Pisum sativum (field pea), P. fulvum and Lathyrus species was examined in glasshouse experiments using an isolate of the fungal pathogen Mycosphaerella pinodes that had been isolated from field pea. In the genus Pisum there was significant variation in stem infection among the primitive field pea lines, the field pea cultivars and the P. fulvum lines. Two P. fulvum lines and one primitive field pea line exhibited significantly less stem infection than the two field pea cultivars. Leaf infection of the primitive field pea lines was not significantly different from that of the field pea cultivars. P. fulvum accession PS1115 had the least stem infection and the least leaf infection among the Pisum germplasm. Examination of stem infection in Lathyrus showed that L. sativus, L. ochrus and L. clymenum accessions were significantly more resistant to stem infection than the field pea cultivars. Six of the eight accessions of Lathyrus were also significantly more resistant to leaf infection than the field pea cultivars. Among ten accessions of L. sativus, there was significant variation in severity of stem infection but not leaf infection. This is the first report comparing ascochyta blight resistance between Lathyrus and Pisum species and among Lathyrus accessions and the results show that Lathyrus species may be a source of resistance alleles that could be exploited to develop ascochyta blight resistance in field pea.