In vivo and in vitro performance studies on groundnut (Acharis hypogea L.) genotypes for yellow witchweed (Alectra vogelii Benth.) resistance

Witchweed (Alectra vogelii Benth.) is a legume parasitic weed that causes severe yield reduction of groundnut (Acharis hypogea L.) in Africa. The study was conducted to screen and identify Alectra vogelii resistant and/or tolerant groundnut genotypes evaluated under both laboratory and glasshouse at the University of Zimbabwe during 2018/19 cropping season. The findings of the lab agar-gel screening experiment revealed significant differences in germination percentage and germination distance between genotypes. Significant genotype x A. vogelii infestation interaction on plant biomass, root to shoot ratio and shelled grain yield were observed. Alectra vogelii parasitism significantly reduced plant biomass and shelled grain yield across groundnut genotypes. Conversely, genotypes like Njiva, Ilanda and Guinea fowl did not support any haustorial attachment, and had the highest shelled grain yield under all A. vogelii infestation levels. Assessment of A. vogelii tolerance based on groundnut growth, physiological and yield related parameters revealed that the groundnut genotypes Njiva, Ilanda and Guinea fowl tolerated A. vogelii infection, whereas Dendera, Jessa, Nyanda and Tern could be susceptible. Field studies are expected to validate the initiative of breeding with farmers of tolerance groundnut genotypes to A. vogelii infection.