Insect resistance in sorghum plants

Abstract

Sorghum (Sorghum bicolor) is an important food crop, especially of the semi-arid areas of Asia and Africa. One of the major constraints affecting the popularity of high-yielding hybrids and varieties is their extremely high susceptibility to insect pests. Painter (1951) has reviewed in detail the work done on resistance in sorghum to the chinch bug (Blissus leucopterus), corn leaf aphid (Aphis maidis) and sorghum midge (Contarinia sorghicola). In the last decade and a half considerable work has been done on resistance to the shootfly (Atherigona seccata), stem borer (Chilo partellus) and sorghum midge (Contarinia sorghicola). By conducting multilo-cation screenings of world germplasm under natural and artificial infestation conditions, not only have promising sources of resistance been identified but a number of them have been utilised in crossing programmes to develop high-yielding resistant cultivars. Some sources with multiple resistance have also been identified. The mechanisms of resistance in sorghum to the major pests have been investigated. It is seen that the mechanisms are generally complex and the observed field resistance is the total reaction of several components. There are several leads available which justify further intensive work, especially on identifying naturally occurring plant products associated with antibiosis mechanism