Vesicular arbuscular mycorrhizal influence on growth of cancer bush (Sutherlandia frutescens) and alleviation of saline stress

Lack of arable land on a global scale, agricultural malpractices and high soil salinity have prompted the development of alternative eco-friendly ways to increase crop production. The usage of vesicular arbuscular mycorrhizal (VAM) has been reported to positively improve crop production under harsh soil conditions but no such effort has fixated on traditional underutilized crops such as cancer bush (Sutherlandia frutescens). Given its significance as a versatile remedial crop, it is critical to cultivate this plant and regulate the agronomic necessities for its effective cultivation. Therefore, two separate experiments were conducted at the University of Mpumalanga, Mbombela, South Africa in 2021 and 2022, with an objective to investigate whether VAM will improve growth of cancer bush under saline soil conditions. Three weeks old cancer bush seedlings were planted in pots under microplot conditions. The in a 4 x 4 factorial treatmentarrangement in a randomized complete block design. The seedlings were grown in four geometric series of NaCl : CaCl2 (3 : 1) of artificial chloride salinity levels: 0, 0.25, 0.5 and 0.75 ds/m and four levels of VAM: 0,10, 20, and 30 g/pot, with four replications in the two successive years. At 60 days after initiation of treatments, dry root mass and number of branches were significantly affected by treatments in Experiment 1, with total treatment variation (TTV) of 11-17 and 9-34%, respectively of the variables. Dry shoot mass was significantly affected by treatments in Experiment 2, with TTV of 26-32%. In both the experiments, treatments had significant effects on soil EC, contributing 26-42% in TTV in Experiment 1, whereas in Experiment 2 the treatments contributed 4-76% in TTV of the respective variable. In conclusion, findings in the current study demonstrated that VAM in presence of salinity improved growth relative to plants under saline stress.