<p>Rational application of chemical fertilizer increases crop yield of biofortified bean. This study aimed at determining the optimal dose of chemical fertilizer to apply on two biofortified bean varieties used in the community in order to maximize their yield. Following a split-plot design, a field experiment was carried out on CODMLB001 and HM21-7 varieties, in Kashusha (Kabare territory) in Sud-Kivu Highlands, after a strategic application of increasing doses of chemical fertilizer NPK 17-17-17 (D₀: Control; D₁: 50 kg ha^-1; D₂: 75 kg ha^-1; D₃: 100 kg ha^-1; D₄: 125 kg ha^-1 and D₅: 150 kg ha^-1). The said doses were applied on the sowing day in a parallel gutter at 5cm from the sowing line. The germination rate, the number of days at both the flowering stage and the stage of physiological maturity, as well as the number of harvested crops and beans per plant, number of beans per pod, weight per 1000 grains and yield were observed. Positive and negative interaction between different increasing doses of chemical fertilizers regarding the two varieties were observed. This strategic application allows increased performance according to considered varieties and doses. For instance, the HM21-7 variety gave the best performance with the D₅ dose, while the CODMLB001 variety did better under <em>D₂</em>.</p>

This study investigated the influence of three soil moisture irrigation regimes on concentration of seed iron and zinc content of four biofortified bean varieties promoted for eradication of malnutrition in Sud-Kivu highlands. A field experiment was conducted in the Hogola marsh highlands during two cultural seasons B2013 and B2014. The experiment design was a RCBD with a split plot arrangement where the main plots were 110 m 2 and split plots 20 m 2 . A strategic application of homogenisation of the experimental site's soil fertility by chemical fertilizers of the type: CaCO 3 , KCl and DAP was conducted out. Four biofortified varieties (CODMLB001, RWR2245, HM21-7 and RWK10) constituted main factor, while water regimes respectively [bottom of the slope: R1 = 48% soil moisture, at the middle of the slope R2 = 37% soil moisture and at the top of the slope: R3 = 29% soil moisture according to the gradient of humidity] represented secondary factor and seasonality, tertiary factor. The study showed that the concentrations of iron and zinc were highly correlated with soil moisture regimes. The variety HM21-7 demonstrated better adaptability because it showed a low rate of reduction of iron and zinc concentration under the three soil moisture regimes and was therefore best suited to fight malnutrition in the Sud-Kivu province.