The resistant patterns and mechanism of biochemical resistance in various wheat cultivars (lines).
Seedlings of 10 winter wheat cultivars (lines) with different degrees of resistance to Sitobion avenae (SA) and Rhopalosiphum padi (RP) were investigated under laboratory conditions. Data were recorded on life tables, resistant patterns and secondary substances in plant tissues. Results showed that resistant patterns of cultivars were non-preference (30%) and antibiosis (70%). The non-preference resistant cultivars made aphids crawling frequently and decreased colonial rates on wheat leaves, but colonial individuals and their growth rate and fecundity were as CK. Cultivars with different degrees of antibiosis resistance resulted in prolonged nymphal development of SA and RP by 2.1-28.2% and 3.7-13.9%, respectively. Nymphal mortality increased 1.0-3.6 and 1.0-2.25 times, average longevity shortened by 10.2-96.5% and 37.5-97.1%, and fecundity decreased by 3.4-72.8% and 25-97.2%, respectively. Significant differences in tannin and phenolic contents existed between resistant and susceptible cultivars. Correlations between phenolic contents and the resistant degree to SA, and phenolic contents and innate capacity for increase (rm) of SA were negatively significant. No correlation between phenolic content and resistant degree to RP or rm of RP was found. There was no correlation between tannin content and resistant degrees.