Response of maize (Zea mays L.) to varied moisture levels under Striga lutea (Lour) infestation in Nigeria

Laboratory and glasshouse trials were used to determine the response of maize plants to varied moisture levels under Striga lutea infestation. Six moisture levels (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 ml) were applied to striga seed for germination count in the laboratory, while five moisture levels (300, 600, 900, 1200 and 1500 ml) were applied to two maize varieties infested with Striga lutea to assess their tolerance to striga in the glasshouse. The results showed decline in striga germination counts with increased moisture supply in the laboratory and daily moisture application. Supply of 2.00 ml of moisture seemed enough for optimum striga germination. Results from a glasshouse trial also showed significant effects of moisture on striga and maize agronomic characters, except for maize flag leaf length and grain yields. The maize varieties also differed significantly for striga syndrome rating, plant height, and maize grain yield, while variety × infestation as well as variety × moisture differed significantly for almost all the traits assessed. The interactive effects of variety × moisture were significant for all variables except grain yield. Similarly, gradual increase in striga emergence at higher moisture levels from 1.3 (300 m1) to 52.0 (1500 ml) were recorded. Striga syndrome ratings were significantly reduced with increased moisture, thereby enhancing higher grain yield. The use of striga- resistant genotypes in addition to adequate soil moisture will probably boost maize production in striga-endemic areas.Les essais de laboratoire et de serre se sont déroulés à l'Institut de Recherche et de Formation Agricole, Université d'Obafemi Awolowo, Plantation de Moor, Ibadan, Nigeria. Le but était de déterminer la réaction des plantes de maïs aux niveaux différents d'humidité sous l'infestation de Striga lutea. Six niveaux d'humidité (1.5, 2.0, 2.5, 3.0, 3.5, et 4.0 ml) sous une situation de laboratoire, étaient appliqués aux graines de Striga pour le compte de germination, alors que cinq niveaux d'humidité (300, 600, 900, 1200 et 1500 ml niveaux d'humidité) sous condition de serre étaient appliqués aux deux variétés de maïs infestées de Striga lutea pour l'évaluation de leur tolérance au Striga. Les résultats montraient une baisse des comptes de germination de Striga avec une augmentation en provision d'humidité sous condition de laboratoire et d'application d'humidité quotidiennement. Provision de 2.00 ml d'humidité semble être suffisant pour la germination optimale de Striga. Les résultats de l'essai d'une serre montraient aussi des effets considérables d'humidité sur striga et les caractères agronomiques de maïs sauf l'iris de maïs, longueur de feuille et les rendements de grains. Les variétés de maïs aussi différaient considérablement pour l'estimation de syndrome de striga, taille de plante et le rendement de grain de maïs, alors que variété × infestation ainsi que variété × humidité différaient considérablement pour presque tous les traits évalués. Les effets interactifs de variété × humidité étaient considérables pour toutes les variables sauf le rendement de grain. De la même façon, les augmentation graduelles de l'émergence de Striga aux niveaux d'humidité plus élevée de 1.3 (300 ml) à 52.0 (1500 ml) étaient enregistrées. Les estimations de syndrome de Striga étaient considérablement réduites avec l'augmentation d'humidité améliorant de cette façon le rendement plus élevé de grain. L'utilisation de génotypes résistants au Striga en plus d'humidité adéquate du sol pourrait probablement accroitre la production de maïs dans les zones endémique de Striga. Ghana Journal of Agricultural Science Vol. 39 (1) 2006: pp. 3-1

Grain yield stability of new maize varieties in Nigeria

Seven early maturing open pollinated (OP) and five yellow hybrid maize varieties were evaluated in 1996 under the auspices of the Nationally Coordinated Research Project (NCRP) on Maize. The experiment was conducted in 22 locations representing the different agro-ecologies of Nigeria. Significant location effects were observed for grain yield in the two sets of maize varieties tested. Grain yield was significantly higher in the northern/southern guinea savanna agro-ecologies when compared to the other agro-ecologies. Highly significant varietal differences were found among the OPs and the yellow hybrids. The highest yielding OP variety was TZE Comp.4 DMR BC1 with an average grain yield of 2.43 t ha-1 while the best yellow hybrid was 8522-2 with a mean grain yield of 2.82 t ha-1. Comparison of the results of the OPs and the hybrids showed that the hybrid had an average of 18.2% yield advantage over the OPs. The hybrid maize varieties and four of the seven OPs were found to be stable in grain production across the locations. Significant genotype x location interaction was also observed for both sets of maize varieties. The best hybrid (8522-2) combined stability with high grain yield and wide adaptability. This variety may thus be introduced to farmers throughout the country. RÉSUMÉ Sept variétés librement pollinisés précoces (OPs) et cinq variétés d'hybrides jaunes de maïs ont été évaluées en 1996 sous les auspices du Project National de Coordination de Recherche pour le maïs. L'essai a été conduit dans 22 localités représentant les differentes régions agro-écologiques du Nigeria. Des effets significatifs de localités ont été observés pour le rendement grain dans les deux groupes de variétés de maïs testés. Le rendement grain était significativement plus élevé dans les zones nord/sud de la savanne guinéene comparativement aux autres régions. Des differences variétales significativement très élevées ont été trouvées entre les OPs et les hybrides jaunes. La variété OP au plus haut rendement était TZE Comp. 4 DMRBC1 avec un rendement moyen de 2.45 t ha-1 alors que le meuilleur hybride jaune était 8522-2 avec un rendement moyen de 2.82 t ha-1. La comparaison des résultats des variétés OPs et des hybrides jaunes a montré une moyenne de 18.2% d'avantage de rendement sur les OPs. Les variétés d'hybrides jaunes et les quatre des sept OPs ont été trouvées plus stables en production des graines à travers les localités. Une interaction entre génotype et environnement était significative pour les deux groupes de variétés de maïs. Le meilleur hybride (8522-2) combinait la stabilité avec le rendement élevé et une large adaptabilité. Cette variété peut être introduite aux agriculteurs à travers tout le pays. (Af Crop Science and Production: 2001 9(4): 685-692

Diallel analysis of maize inbred lines for agronomic traits in nitrogen stress and optimal conditions

Increasing demand, soil cultivation pressure and adverse climate change effects necessitated maize production in nitrogen stress soils. This study examined the general combining ability (GCA) of 12 maize inbreds and specific combining ability of their crosses for agronomic traits under varied nitrogen conditions. GCA accounted for 53% of the variation for grain yield (GY) under stress and 40% under optimal condition. GCA contributed over 59% for days to anthesis (DTA) and days to silking (DTS), anthesis-silking-interval (ASI) and ear aspect (EASP) under both conditions. BD74-165 and BD74-161 had positive significant GCA for GY under stress with TZEI12 under optimal and BD74-222 under both conditions. TZEI13 and TZEI16 had positive significant GCA for DTA and ASI under stress, and TZEI12, TZEI11 and BD74-161 under optimal. Additive genes control DTA, DTS and PH; non-additive genes were responsible for ASI, PASP and EASP while both additive and non-additive genes governed inheritance of GY, EH and leaf-senescence (SEN) under stress. Inheritance of GY, ASI, PH, PASP and EASP were due to non-additive genes; DTA and DTS to additive genes while additive and non-additive genes control EH and SEN under opti­mal condition. Inbreds with significant GCA can be parents for GY improvement under respective conditions. Keywords: Combining ability; diallel; low nitrogen; maize lines; stress toleranc

Comparative study of storage methods of maize grains in South Western Nigeria

Laboratory experiment was conducted to assess the efficacy of different storage methods of maize grains in Ibadan (a humid tropical ecology) between year 2002 and 2003. The results shows that storage methods (SM), treatment (Tr), SM x Variety (V) and Tr x V interactions were highly significant for numbers of undamaged maize grains (P<0.05). Second order interaction (SM x Tr x V) was highly significant for undamaged maize grains, while first and second order interaction were also highly significant for initial kernel weight, kernel weight loss, remained kernel weight (RKW), percentage weight loss, tolerance level, as well as number of insects pest responsible for the damage

Yield stability of yellow maize hybrids in the Savannas of west Africa

There is growing interest for yellow maize among farmers and the food and feed industries in West Africa. Testing of maize hybrids in multi-location trials is crucial for identifying adapted high-yielding candidates for quick release. This study was designed to evaluate yield stability of three-way cross yellow maize hybrids across 17 diverse environments in the savannas of West Africa. Highly significant differences (P < 0.001) were observed among hybrids across locations. The interaction between genotypes and environments was significant for grain yield and most other agronomic traits, with high repeatability (0.68) for grain yield across the test environments. The hybrid A1001-19 was found to be the highest yielding, with yield advantage of 10% over the commercial hybrid Oba Super 2. The genotype, genotype by environment biplot identified hybrid A1001-7 as the most stable hybrid with above-average grain yield, followed by A1001-10. However, A1001-19 was relatively stable and was the best hybrid in 12 of the 17 environments across Mali, Nigeria, and Sierra Leone. Kudu and Zaria 2013 were the most discriminating locations for the hybrids. The stable yield performance of A1001-7 and A1001-10, and to a larger extent A1001-19, would benefit farmers and seed producers with limited capacity to handle single-cross hybrids. Hybrid A1001-10 was released by partners, and hybrids A1001-7 and A1001-19 have been evaluated in national performance and on-farm trials for potential release. This would provide more food for resource-poor farmers and raw materials for food and feed industries and would result in increased household incomes of smallholder farmers in West Africa

Application of SSR Markers for Genetic Purity Analysis of Parental Inbred Lines and Some Commercial Hybrid Maize (Zea mays L.)

Aims: Morphological evaluation of seeds and growing plants used for certification for purity and variety distinctness in Nigeria is time consuming and expensive. This experiment set to evaluate the usefulness of SSR markers to determine genetic purity of commercial hybrids and their inbred lines. Place and Duration of Study: Bioscience unit, International Institute of Tropical Agriculture, Nigeria in December, 2011 Methodology: Seedlings of four F1 hybrids and four inbred lines were grown in the screen house of IITA for DNA extraction using Dellaporta method with some modifications. Six Simple Sequence Repeat (SSR) markers were used for Polymerase Chain Reaction (PCR) using Touch-Down PCR profile. The analysis is by fragment analysis as present (1) or absent (0) Mathematical equation to determine genetic purity of the genotypes was developed from the genetic distances matrix. Results: Simple descriptive analysis revealed that average genetic diversity and polymorphism information content (PIC) recorded by the markers was 0.592 and 0.512 respectively. Genetic purity level of inbred lines ranged between 91.3% and 98.7% while the hybrids ranged between 81.3% and 95%. Conclusion: SSR markers are powerful biotechnological tool capable of detecting genetic purity status of Nigerian maize hybrids therefore inclusion of DNA analysis of seeds using SSR markers to determine genetic purity of maize seed is recommended. However, further research work with larger number of seed samples per variety will be needed to validate reliability