Pea weevil (Bruchus pisorum L.) resistance and genetic diversity in field pea (Pisum sativum L.)

Sammanfattning: Field pea (Pisum sativum L.) is an important source of protein in developing countries like Ethiopia. However, the production of field pea is hampered by invasive pests like the pea weevil (Bruchus pisorum L.). In this PhD project, more than a quarter of the field pea accessions available at the Ethiopian Biodiversity Institute (EBI) have been screened for resistance against pea weevils, both under field and greenhouse conditions. The screenings led to the identification of a few relatively less susceptible accessions/genotypes. Repeated field and greenhouse trials revealed that locally released, high yielding varieties are highly susceptible to pea weevil infestation. The lack of strict quarantine systems in Ethiopia to prevent the spread of infested seeds is worsening the pest distribution within the country. Hence, there is an urgent need to develop locally adapted pea weevil resistance varieties. Developing such varieties is the most effective and cheapest approach which can be supported by other integrated pest management techniques like intercropping to minimize or possibly halt economic loss due to this pest. In the present study, we have also developed 15 new EST-SSR markers that could be used for various applications including genetic diversity assessments and genetic mapping as well as for marker assisted selection in P. sativum. Most of these markers are transferable to other taxa of the genus Pisum and related genera. Twelve of these newly developed EST-SSR markers were used to assay the genetic diversity among 46 accessions of P. sativum. This study revealed high genetic differentiation among the accessions which could be valuable for field pea breeding in the future. In addition, the findings could be used as an input for in-situ and ex-situ conservation strategies of the P. sativum and guide future collection missions.