Soybean aphid intrabiotype variability based on colonization of specific soybean genotypes

Area of Science:

• Entomology
• Plant Breeding
• Pest Management

Background:

• Soybean aphid (Aphis glycines) is a major soybean pest in the US.
• Soybean aphid resistance (Rag) genes are crucial for management.
• Four biotypes overcoming Rag genes have been identified since 2000.

Purpose of the Study:

• To compare the virulence of a Moline, Illinois soybean aphid isolate with known biotypes.
• To investigate if soybean aphid isolates within the same biotype exhibit varying aggressiveness.

Main Methods:

• Two no-choice experiments were conducted.
• Virulence was assessed by comparing aphid population counts on soybean genotypes with different Rag genes.

Main Results:

• The Moline isolate colonized Rag2 soybean plants similarly to biotype 3.
• Aphid counts for the Moline isolate were significantly lower than biotype 3 on Rag1 and Rag3 soybean genotypes.
• The Moline isolate was identified as a variant of biotype 3.

Conclusions:

• Soybean aphid isolates classified as the same biotype can differ in aggressiveness.
• This intra-biotype variation impacts the effectiveness of host plant resistance strategies.
• Further research is needed to understand the genetic basis of this variation.