Evaluating Host-Plant Resistance against Sugarcane Aphid (Melanaphis sacchari (Zehntner)) in Sorghum (Sorghum bicolor (L.) Moench)

Abstract

TThe sugarcane aphid (Melanaphis sacchari (Zehntner)) is an established and problematic pest on sorghum (Sorghum bicolor (L.) Moench) in the United States. The virulent pest on sorghum was initially identified in Southeast Texas and significantly affects production. Heavy infestation will decrease yield and quality of grain and forage sorghum. The aphid’s sticky honeydew secretions cause harvest losses and clogging of combines. Using artificial and natural infestations, 500 lines from Texas A&M AgriLife Research were evaluated, including mechanisms of resistance and phenotypic traits useful for breeding.

Resistant lines A/B.Tx3408 and A/B.Tx3409 were identified, and released to the public in 2016. Grain and forage sorghum hybrids produced using resistant lines also exhibited resistance. The resistant lines and hybrids produced from resistant sources were subsequently evaluated for their relative agronomic and breeding value. The performance of resistant hybrids was better than susceptible hybrids under sugarcane aphid infestation. The mechanisms of resistance were identified as antibiosis and antixenosis (non-preference). Some phenotypic traits also influenced aphid damage.

Further investigation into the phenotypic, biochemical and genotypic traits responsible for conditioning sugarcane aphid resistance is planned through heritability and quantitative trait locus (QTL) mapping studies. This will enable more efficient selection of genotypes that maintain grain and/or forage yield and quality when subjected to aphid infestation.