Screening of Maize (Zea mays L.) Genotypes for Adaptation on Contrasted Acid Soils in the Humid Forest Zone of Cameroon

Abstract

Soil acidity is a major limiting factor for maize productivity in the humid forest zone of Cameroon. A yield loss of up to 60% has been reported in acid tolerant population. The objective of this study was to determine the level of tolerance of some selected inbred lines under Aluminum and Manganese toxicities on chosen experimental site soils and to classify them into specific pools. The experiment was laid out in a Split-plot design and genotypes were completely randomized within the blocks. Three replications were used. An assessment of 52 inbred lines of maize which consisted of 25 IRAD Cameroon lines, 3 IITA lines and 24 lines from CIMMYT-Colombia was then carried out in a contrasted acidic soil with Al (Nkoemvone site) and Mn (Nkolbisson site) toxicities based on six agro-morphological parameters. Soil correction was made up by the application of 2 t ha-1 of dolomite lime. The soil analysis revealed that, at Nkolbisson plot there was Mn toxicity of 90. 6 (ug/g), while at Nkoemvone Al toxicity was more presented with 2.32 (cmol (+) kg). At Nkolbisson, 5.76% of the genotypes proved to be efficient, 9.43% were tolerant, 75% were susceptible and 15.09% were negative control. At Nkoemvone, 7.54% of inbred lines expressed themselves as efficient, 3.77% were tolerant, 75.47% were susceptible, 13.20% were negative control and 5.66% of the genotypes presented floral abnormalities called “mentle”. ATP S5 30Y-1 and CML 535 distinguished themselves as ubiquitous and CML 304 was the most susceptible variety to both agro-ecologies. The dendrogram obtained by the non-hierarchical classification analysis of endogamous genotypes showed three groups of maize genotypes at Nkolbisson and four groups at Nkoemvone. The best genotypes at Nkolbisson were: ATP-14 (4.08 t/ha), Camlnb1 17 F (3.93 t/ha), ATP S9 30Y-1 (3.86 t/ha), CML 437 (2.72 t/ha) and CML 535 (2.54 t/ha) and at Nkoemvone were: Clgp1 17 (3.9 t/ha), CML 322 (2.24 t/ha), CML 479 (2.24 t/ha) and CML 533 (2.05 t/ha). Diffusion of these acid-tolerant genotypes offers a sustainable strategy to increase yield productivity of acids soils in the humid forest zones.