Evaluation of Phenological and Morphological Traits in Pea Accessions (Pisum sativum L.) and Their Resistance to Pea Weevil (Bruchus pisorum L.)

Diversity in pea plant germplasm is crucial in breeding programmes to select highly yielding varieties resistant to Bruchid damage. At the Institute of Forage Crops in Pleven, Bulgaria, nine field pea accessions underwent evaluation for resistance to the pea weevil Bruchus pisorum L. The study identified a relationship between the damage inflicted by the weevils and certain phenological and morphological characteristics. Earlier flowering and formatting pod accessions had a lower sum of the effective temperatures and were characterised by low weevil density. Accessions with a low percentage of damaged seeds with Bruchid emergence holes were distinguished by high seed weight and higher-damaged ones with parasitoid emergence holes. The large seeds had low weight loss from weevil larvae, too. Parasitoid Triaspis thoracica reduced weevil larvae when the larvae in damaged seeds were in early instars and can be a successful biological agent of B. pisorum in earlier and shorter flowering and pod formation cultivars. Also, a mechanical barrier, such as the thickness of the pod wall, can limit larvae penetration in the pod and reduce weevil damage. Line 5/04-8 and L 5/01-3 were classified as resistant to B. pisorum and could be used in future breeding programmes such as resistant sources.