The Triticeae as sources of hydroxamic acids, secondary metabolites in wheat conferring resistance against aphids

Hydroxamic. acids of the 2,4-dihydroxy-l,4-benzoxazin-3-one type (DIBOA; DIMBOA = 7-methoxy derivative) play an important role in the resistance of wheat to aphids, through antibiosis and feeding deterrency. Screening of species of the tribe Triticeae has identified useful sources of hydroxamic acids for breeding programs to increase aphid resistance in wheat. It is shown that hydroxamic acids may be used as taxonomic markers. On this basis, it is suggested that Trilkum speltoides is a likely donor of the B genome to hexaploid wheat.