Md. Lazar et al., REPRODUCTIVE AND DEVELOPMENTAL RATES OF 2 GREENBUG BIOTYPES IN RELATION TO 2 WHEAT HOST-RESISTANCE GENES, The Southwestern entomologist, 20(4), 1995, pp. 467-482
The reproductive and developmental parameters of biotypes C and E gree
nbug, Schizaphis graminum (Rondani), restricted to feeding on each of
four host wheat, Triticum aestivum L., genotypes was investigated. Whe
n reared on TAM105 and TAM107 winter wheat cultivars (susceptible and
resistant, respectively, to biotype C greenbug based on allelic variat
ion at the Gb2 locus), biotype C greenbugs differed significantly in c
umulative number of nymphs produced (72.60 and 19.74, respectively), i
ntrinsic rate of increase (0.244 and 0.113, respectively), and total d
ays required for nymphal development (5.37 and 6.73), respectively. Bi
otype E greenbugs reared on the same cultivars (both of which are susc
eptible to biotype E), exhibited significant differences in cumulative
nymphs per adult (64.02 and 53.46, respectively) and in total lifespa
n (26.61 and 17.78, respectively), but not in intrinsic rate of increa
se (0.212 and 0.217, respectively). Two near-isogenic wheat breeding l
ines, each closely related to TAM105 and TAM107, were also evaluated.
Biotype-E resistant TXGBE273 and biotyye-E-susceptible TXGBE307 are di
stinguished by differing alleles at the Gb3 locus. While the two breed
ing lines were not distinguished by any measures of biotype C developm
ent or reproduction, biotype E aphids produced significantly more cumu
lative nymphs per adult on susceptible TXGBE307 (42.27) than on resist
ant TXGBE273 (25.00). The antibiotic factors contributing to resistanc
e to both biotypes were generally more related to effects on reproduct
ion than to developmental effects. Significant effects of biotype C re
sistance were observed on reproduction in biotype E, although that eff
ect was offset by differences in mean generation time in one of the wh
eat lines.