Unraveling Seed Dormancy and Host Specificity of Alectra Vogelii in Malawi

Parasitic angiosperm Alectra vogelii Benth is a growing problem in Malawi, particularly with the current emphasis on legume crops. Therefore, a pot experiment was conducted in Lilongwe, Malawi to evaluate the effects of site, A. vogelii dormancy-breaking period on Mkanakaufiti and IT82E-16 cowpea varieties. Varieties of cowpea were grown in A. vogelii-infested pots sourced from three agroecological zones and subjected to varied dormancy-breaking periods. The experiment was arranged in a Randomized Complete Block Design and replicated four times. The study revealed that dormancy breaking had impacts depending on the A. vogelii source. However, the Alectra source affected the A. vogelii shoot counts and cowpea grain weight. Neno-Manyenye collections had a higher incidence without induced dormancy breaking periods while Lilongwe-Kamowa, and Salima-Matumba collections had a high incidence after the dormancy-breaking period. Late infestation (at 119 to 149 days after planting) on resistant Mkanakaufiti cowpea variety by A. vogelii collections used indicated apparent strain variability of collections used. The results confirmed the delayed resistance mechanism of Mkanakaufiti against A. vogelii. Nevertheless, the variety reactions on the parasitic weed depends on suitability, compatibility, and specificity, although some resistant genotypes tend to lose the resistance mechanism with time. A. vogelii seeds organic carbon % varied (4.87±1.73 to 9.13±0.95) from the three agroecological zones which signified the collections’ variability due to warmer temperatures, relative humidity, and crop husbandry practices under long-term conditions. Therefore, screening efforts for resistance or evaluation of agronomic options to suppress the weed should be intensified.