Phenotyping Pisum sativum germplasm for resistance to aphid (Acyrtosiphon pisum) and weevil (Bruchus pisorum) under field and controlled conditions

Abstract

Pea weevil (Bruchus pisorum, Bp) and pea aphid (Acyrthosiphon pisum, Ac) are highly destructive pests affecting pea (Pisum sativum) production worldwide. Bp larvae feed into seeds decreasing the quality and marketability of the seeds. Ac is a sap-sucking insect of several legumes species, which causes significant yield losses and transmit viruses. Chemical control is possible but requires repeated treatments with the associated detrimental environment effects. Here we report the phenotyping studies performed in our department to identify and characterize pea resistance against both pests. Field assessment consisted on monitoring plant traits that might contribute to scape mechanisms, and assessing pest incidence and severity and plant damage. For Bp separate assessments were made on percentage of infected seeds, and the level of larval development as they can reflect possible antixenosis and antibiosis mechanisms, respectively. In addition to field observations, we performed no-choice and multiple choice bioassays with selected accessions under semi controlled and controlled conditions to corroborate and characterize the resistance mechanism detected in field. This allowed the elucidation of antixenosis, antibiosis and tolerance mechanisms.