Letter | Published:

Resistance of Sorghum to Witchweed


STRAINS of Sorghum vulgare resistant to root parasite witchweed (Striga lutea) have been bred in South Africa over a number of years.1 One of these (var. ‘Framida’) is characterized by its inability to germinate the parasite seed, which requires a stimulatory substance normally excreted from the host plant roots. A comparison of the resistant variety ‘Framida’, and a susceptible variety ‘Light Mori’ (from Nigeria) illustrates this point very clearly. Seedlings of the two varieties were grown in coarse washed sand in 3-in. plastic pots (50 seedlings per pot) for a period of nine days at ambient temperature (23–31°C.). After this the root solutions were eluted with 20 ml. of distilled water. The eluted solutions were tested for their ability to germinate the parasite seed in Petri-dish culture at full strength (as eluted) and at dilutions of 1:10 and 1:100. Typical results are shown in Fig. 1. It can be seen that the concentration of germination stimulent from the susceptible variety (‘Light Mori’) is supra-optimal and that a dilution of 1:10 does not reduce germination of the parasite seeds significantly. In the resistant variety, however, a similar dilution reduces germination almost completely; while even at the highest concentration germination is significantly lower. Since it is unlikely that a concentration of root growth stimulant approaching that of the experimental conditions will be encountered in Nature, this seems to be at least one mechanism by which resistance is achieved.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Saunders, A. R., South Afr. Dept. Agric. and For. Sci. Bull., 14, (1942).

  2. 2

    Saunders, A. R., Sci. Bull. Dept. Agric. South Afr. (1933).

  3. 3

    Elliot, B. B., and Leopold, A. C., Physiol. Plantarum, 6, 65 (1953).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.