Breeding for Resistance to Parasitic Weeds
There are some parasitic weeds which cause significant yield losses in may crop plants. Parasitic weeds extracts water ad minerals from the host and secrete toxins from their roots, which inhibit normal growth and development of the host plant. There are 2500 species of parasitic weeds belonging to 10 families. However, three parasitic weeds namely. Cuscuta spp. (dodders), orobanche spp (brown rope), are of major concern in field crops. Cuscuta spp is the most serious pest of sugar beet in Turkey. Severe attack of this parasite causes heavy yield losses in Sugarbeet. This weed attacks on the aerial parts. Orobanche spp. is the serious pest of legumes, tobacco, tomato, potato, cotton, sunflower, etc. In Europe, Asia, Africa , USA and Russia. Extracts water nutrients and salts from the vascular system of host plant by means of haustoria. It attacks on the roots, cucurbits, sunflower legumes and pasture grasses in Asia. Africa and USA and cause damage like Orobanchea spp. by attacking on roots of the host.
In India, Striga spp. attack on sorghum crop in some parts of Maharashtra. The genetic resistance plays an important role in controlling Orobanche and Striga. This variety gives good yield in Striga prone areas of Maharashtra ICARDA, Syria. The source of resistance have been identified in the chickpea gee pool maintained at ICARDA. Resistant varieties of sunflower to Orobanche have been developed in Russia. However, very little information is so far available on the inheritance of research to overcome the problems of parasitic weeds in problematic areas.