Variation among Accessions of Pisum fulvum for Resistance to Pea Weevil
- S. L. Clement *a,
- D. C. Hardieb and
- L. R. Elbersona
The pea weevil, Bruchus pisorum (L.) (Coleoptera: Bruchidae), is one of the most intractable pest problems of cultivated pea, Pisum sativum L. The availability of resistant cultivars would give growers more pest management options. Searches for plant resistance to pea weevil were expanded to the Pisum secondary gene pool (P fulvum Sm.) because seed resistance had not been located in P sativum and subspecies. The objectives of this study were to determine the extent of pod and seed resistance to pea weevil in P fulvum, and to use the life table format to characterize weevil stage-specific mortality and survivorship on different P fulvum accessions. Mortality of first instar larvae on pods, mortality of all weevil stages within seed, adult emergence from seed, and seed damage levels were quantified. In two greenhouse trials, more larvae died (14 to 50% averages) on pods of P fulvum accessions than on pods of ‘Alaska 81’ (6% average), and mortality of first instar larvae entering seed of P fulvum accessions averaged 83.7%. Seed damage ratings (1 = feeding scar on seed testa, 0-1% cotyledon tissue eaten, dead first instar larva; 5 = extensive damage, live adult) averaged <3.0 for 26 P fulvum accessions, compared with mean ratings of 4.9 for Alaska 81. Using weevil mortality and survivorship values in life tables and adult emergence rates, entries were classified as susceptible (two controls and five accessions), moderately resistant (14 accessions), and resistant (12 accessions). Antibiosis resistance was based on the death of weevil larvae on pods and seed testa and cotyledon tissues. The results identify sources of natural weevil resistance in the Pisum genome (26 moderately resistant and resistant accessions of P fulvum) to endow pea cultivars with pod and/or seed resistance to B pisorumPlease view the pdf by using the Full Text (PDF) link under 'View' to the left.
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