RESPONSE OF GROUNDNUT (Acharis hypogea L.) GENOTYPES TO YELLOW WITCHWEED (Alectra vogelii (Benth.) INFESTATIONS

Witch weed (Alectra vogelii Benth) is a parasitic weed of legumes which causes severe decrease in yield of groundnut in Africa, where the crop is an important source of protein for resource poor farmers. The use of Alectra resistant groundnut genotypes is one of the sustainable and effective ways to control this weed. A project aiming to establish the response of different groundnut genotypes to Alectra infestation and groundnuts level of Alectra resistance and tolerance was conducted at the University of Zimbabwe. Seven groundnut genotypes were screened using the laboratory agar-gel technique and pot experiments under glasshouse at the University Zimbabwe during the 2018/19 cropping season. All experiments were laid out in Randomized Complete Block Design. The pot experiment was laid out as a 7(groundnut genotypes)*2(Alectra infestation: infested and non-infested) factorial experiment with six replications. In the laboratory, the agar-gel screening experiment revealed significant (p<0.05) differences among genotypes in terms of germination percentage and furthest germination distance. Dendera and Nyanda had significantly (p<0.05) higher germination percentage and furthest germination distances (2 mm and 3.34 mm) respectively. There were significant (p<0.05) genotype x Alectra interactions on plant biomass, shoot to root ratio and shelled grain yield. Alectra parasitism significantly (p<0.001) reduced plant biomass, shoot to root ratio and shelled grain yield across all groundnut genotypes. On Alectra attachments on the roots of groundnut genotypes, significant (p<0.05) differences were recorded on infested groundnut genotypes. Njiva did not support any haustorial attachment, and had the highest shelled grain yield under all Alectra levels which is a good indication for resistance. The groundnut genotypes Ilanda and Guinea fowl seem to be tolerance genotypes based on their plant biomass, shoot to root biomasses produced and shelled grain yield as compared to other genotypes.