Growth, physiological and yield response of provitamin A biofortified maize cultivars to different natural environments

Malnutrition remains a main problem in sub-Saharan Africa regardless of the applied interventions to combat food and nutrition insecurity. Biofortication of staple crops has been regarded as the latest intervention strategy to combat micronutrient diseases such as vitamin A deficiency in developing countries in southern Africa. The aim of the study was to determine the response of provitamin A biofortified maize cultivars under different environmental conditions. A randomized complete block design with five cultivars, two provitamin A varieties and three common maize varieties were planted in two on farm trails located under different agro-ecological zones (Bulwer and KwaDlangezwa) of KwaZulu-Natal in a two-season period (2015/16 and 2016/17). The five cultivars namely Border king (BK), provitamin A biofortified maize (PVABM), local landrace (LL), SC 506 and SC510 recorded a highly significant (P<0.001) plant growth (height and leaf number) in both experimental sites across two seasons (2015/16 and 2016/17). Chlorophyll content showed no significant differences for both trial sites in both 2015/16 and 2016/17 seasons. For the first season, no significant differences (P< 0.05) were observed for biomass among the maize varieties in both trial sites. However, it was observed that SC510 had higher biomass (2.33 t/ha), while BK recorded lowest biomass (0.66 t/ha) in Bulwer. In KwaDlangezwa, the biomass ranged from 0.713 t/ha (PVA) to 1.66 t/ha (SC510). For the second season (2016/17), Biomass in Bulwer ranged from 0.86 t/ha (LL) to 1.52 t/ha (SC510) and 0.94 t/ha (BK) to 1.44 (SC510) in KwaDlangezwa. The performance of the provitamin A biofortified varieties (SC510 and PVABM) showed that they can adapt and produce similarly to common varieties. It is noted that there is potential for these varieties to adapt under different environmental conditions of KwaZulu-Natal, South Africa. The provitamin A biofortified varieties can be produced for human consumption at common smallholder farming systems.