An experiment was conducted from 1997 to 2000 on an acid soil in Cameroon to assess the effectiveness of cultivating acid tolerant maize (Zea mays L.) cultivar and the use of organic and inorganic fertilizers as options for the management of soil acidity. The factors investigated were: phosphorus (0 and 60 kg ha )1 ), dolomitic lime (0 and 2 t ha )1 ), organic manure (no manure, 4 t ha )1 poultry manure, and 4 t ha )1 of leaves of Senna spectabilis), and maize cultivars (ATP-SR-Y -an acid soil-tolerant, and Tuxpen˜o sequiaan acid susceptible).On acid soil, maize grain yield of ATP-SR-Y was 61% higher than the grain yield of Tuxpen˜o sequia. Continuous maize cultivation on acid soil further increased soil acidity, which was manifested by a decrease in pH (0.23 unit), exchangeable Ca (31%) and Mg (36%) and by an increase in exchangeable Al (20%). Yearly application of 60 kg ha )1 of P for 3 years increased soil acidity through increases in exchangeable Al (8%) and H (16%) and a decrease in exchangeable Ca (30%), Mg (11%) and pH (0.07 unit). Lime application increased grain yield of the tolerant (82%) and susceptible (208%) cultivars. The grain yield increases were associated with a mean decrease of 43% in exchangeable Al, and 51% in H, a mean increase of 0.27 unit in pH, 5% in CEC, 154% in exchangeable Ca, and 481% in Mg contents of the soil. Poultry manure was more efficient than leaves of Senna producing 38% higher grain yield. This yield was associated with increases in pH, Ca, Mg and P, and a decrease in Al. The highest mean grain yields were obtained with lime added to poultry manure (4.70 t ha )1 ) or leaves of Senna (4.72 t ha )1 ).Grain yield increase was more related to the decrease in exchangeable Al (r=)0.86 to )0.95, P<0.01) and increase in Ca (r=0.78-0.94, P<0.01), than to pH (r=)0.57 (non-significant) to )0.58 (P<0.05)). Exchangeable Al was the main factor determining pH (r=)0.88 to )0.92, P<0.01).The yield advantage of the acid tolerant cultivar was evident even after correcting for soil acidity. Acid soil-tolerant cultivars are capable of bringing unproductive acid soils into cultivation on the short run. The integration of soil amendments together with acid soil-tolerant cultivar offers a sustainable and comprehensive strategy for the management of acid soils in the tropics.

Nitrogen (N) is one of the most important nutrients required for high productivity of the maize plant. In most farmers' fields in Sub-Saharan Africa (SSA), there is low availability of N in the soil mainly due to continuous cultivation of the land, crop residues removal, little or no application of fertilizers and rapid leaching. There is a need to develop low N tolerant and adapted maize genotypes. Evaluation of maize genotypes under different nitrogen conditions would therefore be useful in identifying genotypes that combine stability with high yield potential for both stress and non-stress environment. Eighty maize hybrids were evaluated at Mbalmayo and Nkolbisson in Cameroon, during 2012 and 2013 minor and major cropping seasons across 11 environments under low and high N conditions. The objectives of the study were: (i) to determine the effect of genotype x environment interaction (G × E) on grain yield and yield stability of single cross maize hybrids across low N and optimum N environments and (ii) to identify genotypes to recommend for further use in the breeding program. Yield data of 80 hybrids were analyzed initially and the analysis of 20 best performing genotypes was further performed for a better visualization and interpretation of the results. Combined analysis of variance showed highly significant G × E effects for grain yield. The GGE biplot analysis divided the study area into three mega environments: one related to the major cropping season while the two others were related to the minor cropping season. The grain yield of the 20 highest yielding hybrids ranged from 4484.7 to 5198.3 kg ha −1. Hybrid 1368 × 87036 was the highest yielding in the minor season while the most outstanding hybrid, TL-11-A-1642-5 × 87036 was the best for the major season. The latter hybrid showed the potential for production across environments and should therefore be further tested in multiple environments to confirm consistency of its high yield performance and stability, and to facilitate its release as a commercial hybrid. High yielding but not stable hybrids across environments could be recommended for the specific environments where they performed well.

Grain-yield potential of maize (Zea mays L.) is limited by the harsh climatic conditions during dry seasons in the savanna of sub-Saharan Africa (SSA). One hundred and five hybrids derived from diallel crosses involving 15 early-maturing yellow maize inbreds were screened under combined drought and heat stress (CDHS) and well-watered (WW) conditions at four locations representative of the dry savannas of Niger, 2012–2014. The objective of the study was to examine the general combining ability (GCA) effects of the inbred lines and specific combining ability (SCA) of the crosses under CDHS and WW environments, assess yield and stability of the derived hybrids under contrasting environments and investigate inter-relationships among traits of the hybrids under contrasting environments. GCA and SCA effects for grain yield and other measured traits were significant, with preponderance of GCA effects over SCA effects under both the CDHS and WW environments. Inbred ENT 13 possessed positive and significant GCA effects for grain yield under both CDHS and WW environments indicating that the inbred could be used for developing outstanding hybrids with good levels of tolerance to CDHS. This also implied that the inbred line could serve as invaluable genetic resource for introgression of favorable alleles into tropical early-maturing maize populations for accelerated genetic gains from selection for improved grain yield. Hybrids ENT 13 × TZEI 167 and TZEI 157 × ENT 13 were the most stable and among the highest yielding hybrids across research environments. These outstanding hybrids could be tested extensively for commercialization in SSA to improve food security. Plant and ear aspects and days to 50% silking could be combined with grain yield in a selection index for improvement of yield under CDHS without yield penalties under WW environments.

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This study investigates the effect of Gliding Arc Plasma Activated Water (GAPAW) technique on maize germination and growth variables. The effect of GAPAW was evaluated on corn texture, water absorption in Lab conditions, and the pathway Scanning electron microscopy (SEM) analysis of corn seeds was also carry out. Maize seeds were sown 150 m2 and then watered with tap water and with GAPAW. Seed germination, maize growth and chlorophyll content were evaluated in field conditions in a complete randomized block design with four replicates using the Acid Tolerance Population (ATP) variety. Seed texture treated with 15 min of GAPAW making it darker than those of the control (tap water). Pathway SEM analysis showed no change for the 5 min-GAPAW-treated seeds compared to the control but at 15 min-GAPAW significant changes were observed. Germination was 100% at the 15 min-GAPAW compared to the other treatments (0 and 5 min). Stem length, leaf width, collar diameter, chlorophyll content and water uptake have higher values on plants watered with 15 min-GAPAW compared to others treatments. This application could highlight the germination properties of GAPAW in crop production.