Author
Hesler, Louis | |
DASHIELL, KENTON - International Institute Of Tropical Agriculture (IITA) |
Submitted to: The Open Entomology Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/15/2011 Publication Date: 8/30/2011 Citation: Hesler, L.S., Dashiell, K.E. 2011. Antixenosis to Aphis glycines (Hemiptera: Aphididae) among soybean lines. The Open Entomology Journal. 5:39-44. Interpretive Summary: The soybean aphid has become a major pest of soybean in North America with large outbreaks that cause significant yield loss. Host-plant resistance is one management tactic being developed against soybean aphid in North America, and non-preference for particular strains of plants (also termed antixenosis) is one of three general ways that resistance may be manifested. In this study, four choice tests were conducted to determine preference and non-preference among several soybean lines. Soybean aphid showed strong non-preference for the soybean lines known as ‘Dowling,’ PI 230977, ‘Jackson,’ ‘Cobb’ and ‘Palmetto,’ and an intermediate level of non-preference for lines PI 71506, G93-9223, ‘Braxton,’ ‘Cook,’ ‘IAC-1,’ ‘Ripley,’ and ‘Tie feng 8.’ In contrast, several known aphid-susceptible lines were preferred by soybean aphid. The intermediate level of non-preference for PI 71506 contrasts with previous results, and suggests geographical and biological peculiarities in soybean selection by soybean aphid. Soybean shoot length, shoot width, and seedling dry mass were also measured to test for any association between aphid plant choice and plant size. Plant-size parameters varied by soybean line in all tests. However, the relation between aphid plant choice and plant size was inconsistent and generally weak across tests, suggesting that other undetermined plant characteristics were important than size in plant selection. The identification of non-preference in several soybean lines provides soybean breeders and pest management practitioners with additional options for managing soybean aphid through host-plant resistance. Non-preference may prove to be an important mode of resistance on its own, and it may be complimentary to modes of resistance that disrupt soybean aphid biology that are collectively termed antibiosis. In particular, pairing non-preference with antibiosis may reduce the ability of soybean aphid to further overcome antibiosis resistance and prolong the general usefulness of plant resistance as a non-chemical means of managing the soybean aphid. Technical Abstract: The soybean aphid, Aphis glycines, is a pest of soybean in Asia, and it has become a major pest of soybean in North America with large outbreaks that cause significant yield loss. Host-plant resistance is one management tactic being developed against soybean aphid in North America, and the resistance may be manifested as antixenosis, antibiosis, or tolerance. In this study, choice tests were conducted to identify antixenosis to soybean aphids in several soybean lines. The soybean lines ‘Dowling,’ PI 230977, ‘Jackson,’ ‘Cobb’ and ‘Palmetto’ had strong antixenosis to soybean aphid, and lines PI 71506, G93-9223, ‘Braxton,’ ‘Cook,’ ‘IAC-1,’ ‘Ripley,’ and ‘Tie feng 8’ were moderately antixenotic. The intermediate level of antixenosis in PI 71506 contrasts with previous results, and suggests biotypic differences in the responses of soybean aphid to this line. Shoot length, shoot width, and seedling dry mass were also measured to test for any association between aphid host choice and plant size. Plant-size parameters varied by soybean line in all tests. However, the relation between aphid host choice and plant-size parameters was generally weak and not consistent across tests, suggesting that other undetermined plant characteristics were important in host selection. The identification of antixenosis in several soybean lines provides soybean breeders and pest management practitioners with additional options for managing soybean aphid through host-plant resistance. The importance of antixenosis in soybean as a resistance modality for soybean aphid management is discussed. |