Meloidogyne Incognita Host Suitability and Benzoxazinoid Content of Rye (secale cereale) Cultivars

Authors: Zasada, Inga; Rice, Clifford; Meyer, Susan

Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2006
Publication Date: 2/1/2007
Citation: Zasada, I.A., Rice, C.P., and Meyer, S.L. 2007. Improving the use of rye (Secale cereale) for nematode management: potential to select cultivars based on Meloidogyne incognita host status and benzoxazinoid content. Nematology. 9:53-60.

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that attack plants and cause ten billion dollars in crop losses annually in the United States. Farmers face an enormous problem because they lack safe and effective ways of reducing the numbers of nematodes in soils. Cover crops are crops planted to control soil erosion, to improve soil quality and/or to control plant-parasitic nematodes. In this study, experiments were conducted to determine the nematode-suppressing ability and the chemical compositions of different cultivars of one widely-used cover crop--rye--which produces compounds toxic to nematodes. The cultivars did not differ greatly in the types or concentrations of chemicals toxic to nematodes but did vary in their ability to be a host to the nematode. These results are significant because they will help guide the selection of an appropriate rye cultivar for nematode management. Therefore, this research will be used by scientists developing the use of rye cover crops for reducing nematode numbers in agricultural fields.

Technical Abstract: This research was conducted to investigate factors which may aid in the selection of a rye cultivar for plant-parasitic nematode management. Six geographically diverse cultivars of rye (Secale cereale) wheat (Triticum aestivum) and hairy vetch (Vicia villosa), were screened for Meloidogyne incognita host suitability. Because the chemical constituents of rye have been shown to suppress M. incognita, the rye cultivars and wheat were also tested for benzoxazinoid content. The rye cultivars were all good or excellent hosts but varied in their M. incognita host status. ‘Wrens Abruzzi’, ‘Aroostook’ and ‘Elbon’ were the most resistant cultivars with low eggs/g dry root. Greater than 79% of the rye cultivar’s total benzoxazinoids were comprised of non-methoxy-substituted forms (2R)-2-beta-D-glucopyranosyloxy-4-hydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA-glucoside), 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and benzoxazolin-2(3H)-one (BOA. There was little difference in the concentration of the methoxy-substituted hydroxamic acids (2R)-2-beta-D-glucopyranosyloxy-4-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA-glucoside), 2,4-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), 6-methoxy-benzoxazolin-2(3H)-one (MBOA), and 2-hydroxy-7-methoxy-2H-1,4,-benzoxazzin-3(4H)-one (HMBOA), among the roots of rye cultivars. There were higher concentrations of non-methoxy-substituted benzoxazinoids in the shoots of rye than in the roots. The rye cultivars evaluated in this study did differ in their M. incognita host status, but did not differ greatly in their total benzoxazinoid content early in their development.