Field Screening and Quantifying Sugarcane Aphid Resistant

Sorghum Hybrids Dow/Sorghum Checkoff

Plant/Insect Interaction Resistance ≠ Immunity - It can be defined as:• Effect on insect life history characteristics (antibiosis)• Insect has less preference for one hybrid over another when

provided a choice (antixenosis)• Plant is able protect its yield potential when infested by ‘x’

number of insects that would economic yield loss in another hybrid (tolerance)

The objective of the current study was not to identify mechanisms of resistance but to examine sugarcane aphid (SCA) load compared with a known resistant (RTX2783) and susceptible (RTX430) check

The terms ‘resistant’, ‘moderately resistant’ and ‘susceptible’ will be used to describe differences in degree of susceptibility among commercial products tested

W844E NA NA NA 1 1

83P17 NA NA 2 1 2

84P80 NA NA NA NA 1-2

SP 7715 1 NA NA 1 1-2

SP 6929 2 NA NA 1-2 1-2

SP 78M30 NA NA NA 1 2

SP 73B12 1 NA NA 1 1-2

K73J65 2 NA NA NA NA

RS260E NA NA NA 1 NA

RS84353 NA NA NA 2 NA

1 = Aphid load less than or equal to RTX27832 = Aphid load higher than that on RTX2783 but statistically lower than RTX430 (susceptible check)S = Susceptible (Does not separate from RTX430)

Medium-Full Season Sorghum Hybrids with Sugarcane Aphid Load similar to or less than RTX2783 (Resistant Check)

DG772b NA NA NA NA 1-2

DKS 37-07 NA 1 1 1 1

Pulsar NA NA NA NA 1

1 = Aphid load less than or equal to RTX27832 = Aphid load higher than that on RTX2783 but statistically lower than RTX430 (susceptible check)S = Susceptible (Does not separate from RTX430)

Select Early Season Sorghum Hybrids with Sugarcane Aphid Load compared with RTX2783 (Resistant Check)

Summary Based on aphid load compared with RTX2783, some commercial

products appear to be resistant to SCA

All hybrids and lines exceeded threshold level for SCA…no silver bullet

Sorghum hybrids are adapted to specific regions…do not select a hybrid on its resistance to SCA

Do not sacrifice yield potential or other agronomic characteristics for SCA resistance…there are other tools to manage the SCA

List of sorghum hybrids resistant to the SCA will increase through time.