Taxonomy, evolution and domestication of Vicia in relation to aphid resistance

Abstract

Thirty Vicia species and 28 V. faba cultivars were evaluated for Aphis fabae resistance by measuring rates of aphid population increase (rm) on the host plants. A subset of these species (22) and cultivars (five) were evaluated for resistance to Acyrthosiphon pisum and Megoura viciae. For the same subset of 22 Vicia species and all three aphid species, positive correlations were observed between the concentration and numbers of leaf and stem non-protein amino acids and the level of aphid resistance. Correlations were also observed between trichome density, on some organs of the host, and both nymphal survival and development time. Aphid resistance, together with these possible physical and chemical resistance mechanisms, showed a pattern which was described in relation to the taxonomy of the genus Vicia and the degree of domestication of the host. The least advanced Vicia species were most resistant whilst the more specialised species and those most closely related to V. faba and V. faba itself were most susceptible. Within each taxonomic group (subgenus or section), the most domesticated species were least resistant. The merits of utilising the resistance found in some V. faba cultivars and in other wild Vicia species were considered. 0 1984 Association of Applied Biologists 548 J. HOLT A N D N . B I R C H crop plants including Vicia faba L. (faba bean) and vetches, because a degree of aphid resistance is found in some existing V.faba cultivars, and because V. narbonensis L. (a species closely related to V. faba in the section Faba in which the unknown progenitor of V. faba is placed) has been shown to be relatively resistant to the aphid Aphis fabae (Scop.) (Bond & Lowe, 1975). METHODSVicia species were selected to maximise the number of subgeneric sections (Kupicha, 1976) represented and to include several species from the larger sections. Vicia faba cultivars were selected to represent the three varieties major, equina and minor and groups within these varieties, according to the classification of V.faba cultivars by Higgins, Evans & Reed (1981). Table 1 lists the Vicia species and V.faba cultivars in this study.The resistance of Vicia species and V. faba cultivars to three aphid species Aphis fabae, Acyrthosiphon pisum (Harr.) and Megoura viciae (Buckt.) was investigated by using a simple bioassay technique, similar to that described by Birch & Wratten (1984). Bioassays were performed in Perspex boxes in an insect rearing room similar in design to that described by Scopes, Randall & Biggerstaff (1975). The temperature was 20°C, range 1°C and the light intensity was 75 wE/m2 at foliage level with a photo-period of 16 h. Five plants of each of five cultivars/species were arranged in a randomised block design in each box. Constant experimental conditions were maintained over the period 1979 to 198 1, in which the bioassays were performed. Plants were grown in 10 cm-diameter pots. Viciafaba cultivars were used for bioassays when 4-6 wk old (8 to 10 nodes). Aphid resistance at this plant age corresponded well w...

Research achievements in plant resistance to insect pests of cool season food legumes

“…Laboratory tests conducted alone or in concert with field studies and utilizing caged insects on plant material have also proven useful for evaluation of insect resistance in grain legumes, such as aphid (A . craccivora, A. faba, A. pisum, M. viciae) resistance in the genus Vicia (Birch & Wratten, 1984 ;Holt & Birch, 1984 ;El-Defrawi et al, 1991) and weevil (B. pisorum, S. lineatus) resistance in peas (Noun-Ghanbalani,1977 ;Annis, 1983 ;Pillsbury, 1986) .…”

“…fabae, A. pisum, and M. viciae (Table 3) . Although Holt & Birch (1984) considered the usefulness of partial resistance to aphid pests of faba beans, they viewed the incorporation of high levels of antibiosis from wild Vicia species into faba bean cultivars as a longer term solution to the development of virulent, resistance-breaking aphid biotypes .…”

“…The latter approach clearly has been embraced by chickpea entomologists at ICARDA and ICRISAT (Reed et al, 1987 ;Lateef, 1990 ;Lateef & Pimbert, 1990 ;) . In addition, statements in the literature (Holt & Birch, 1984) and workshops on specific pests (National Pea Weevil Workshop, Victoria, Australia ; Smith, 1990) indicate that entomologists working on insect pests of other grain legumes plan to deploy host-plant resistance as part of integrated control programs . Indeed, traditional methods of pest control, such as the use of insecticides, are often impractical and uneconomical for grain legume producers, especially in the developing countries (Singh et al, 1990) .…”

“…(ICRISAT, 1987) and the storage pest Callosobruchus chinensis (L.) (Weigand & Tahhan, 1990), wild Vicia against the aphids Aphis fabae Scop., Acyrthosiphon pisum (Harris), and Megoura viciae (Buckt.) (Birch & Wratten, 1984 ;Holt & Birch, 1984 ;Birch, 1985), and Lathyrus sativus and L. tingitanus L . against Bruchus pisorum (L.) (Annis & O'Keeffe, 1984) (Table 1) .…”

“…For example, resistance has been evaluated in terms of insect feeding and oviposition preferences (Clement, unpubl . data;Pesho et al ., 1977 ;Pillsbury, 1986), insect infestation levels (Wolfenbarger & Sleesman, 1961, 1963Lateef, 1985 ;El-Defrawi et al ., 1991), and through the effects of plants on insect development, survival, and fecundity (Birch & Wratten, 1984 ;Holt & Birch, 1984 ;Sehgal et al ., 1987 ;Soroka & Mackay, 1991) . Visual rating scales based on percentages or numerical ratings of damage have been used routinely to measure plant susceptibility to insect attack (Wolfenbarger & Sleesman, 1961, 1963Nouri-Ghanbalani, 1974Semenova, 1990 ;Weigand, 1990 ;El-Din Sharaf ElDin, unpubl .…”