Inheritance of antibiosis resistance to the Dectes stem borer, Dectes texanus, in soybean PI165673

Authors: AGUIRRE-ROJAS, LINA - Kansas State University; BUSCHMAN, LAWRENT - Kansas State University; MCCOMACK, BRIAN - Kansas State University; SCHAPAUGH, WILLIAM - Kansas State University; Scully, Erin; ZHU, KUN YAN - Kansas State University; TRICK, HAROLD - Kansas State University; SMITH, CHARLES - Retired Non ARS Employee

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2021
Publication Date: 4/10/2021
Citation: Aguirre-Rojas, L.M., Buschman, L.T., McCornack, B., Schapaugh, W.T., Scully, E.D., Zhu, K.Y., Trick, H.N., Smith, C.M. 2021. Inheritance of antibiosis resistance to the Dectes stem borer, Dectes texanus, in soybean PI165673. Agronomy Journal. 11(4):00738. https://doi.org/10.3390/agronomy11040738.
DOI: https://doi.org/10.3390/agronomy11040738

Interpretive Summary: Soybean stem borer is responsible for major damage to soybeans and cultivated sunflowers in the Great Plains region of the United States. The larval stage is the most damaging as it bores inside the stems of its host plants, which weakens the stem and leads to lodging and yield losses. Unfortunately, there are few effective pest management tactics to reduce soybean steam borer populations once they have become established and insecticides are largely ineffective. Several soybean varieties with resistance to soybean stem borer larvae have been identified; however, the number of genes that are responsible for resistance in many of these varieties is unknown and their modes of inheritance are uncharacterized. To address these knowledge gaps and provide soybean breeders with tools to select for resistance, genetic crosses between a resistant and susceptible soybean variety were performed and resistance was evaluated by counting the number of eggs laid by soybean stem borers and the number of larvae that successfully fed in the stems and by observing whether infested plants exhibited any girdling associated with insect feeding. Experiments indicated that two genes are responsible for conferring resistance to soybean stem borer in the variety tested. Furthermore, fewer eggs were laid and fewer larvae established in lines that carried resistance genes, which resulted in lower damage from feeding. This study suggests that the resistant line used in this study could be crossed with susceptible lines to improve resistance to this pest and that selecting for this trait should be relatively straightforward due to the low number of genes associated with resistance.

Technical Abstract: Dectes texanus larvae girdles stems of soybean and cultivated sunflowers causing significant yield losses in North America. The soybean Plant Introduction (PI) 165673 exhibits antibiosis resistance to the larval stage. The objectives of this study were: 1) determine the inheritance of D. texanus resistance in PI165673, 2) evaluate PI165673 antibiosis resistance before 21 d post infestation, and 3) evaluate girdling damage in PI16563 at the end of the season. K07-1544/PI165673 F2 and F2:3 populations were tested for resistance to D. texanus in 2011 and 2012, and PI165673 antibiosis resistance and girdling damage were evaluated in 2014. Segregation for resistance to D. texanus and heritability estimates in the F2 and F2:3 populations indicated that resistance was controlled by two genes with dominant and recessive epistasis. Antibiosis evaluations indicated: 1) PI165673 contained lower number of larvae and eggs relative to the number of oviposition punctures at 15 d post infestation, 2) proportion of first-instar larvae is higher in PI165673 at 15 d post infestation, and 3) larvae reach sixth-instar stage in PI165673. None of the PI165673 plants were girdled at the end of the season. Identification of additional sources of D. texanus resistance is required to impair larval development in the stem.