Southern Guinea Savanna Ecology Research Articles

Evaluation of Five Improved Maize Varieties for Intercropping with Sweet Potato in Makurdi, Southern Guinea Savanna Ecology of Nigeria

Evaluation of Five Improved Maize Varieties for Intercropping with Sweet Potato in Makurdi, Southern Guinea Savanna Ecology of Nigeria

Genetic Variation for Yield and Yield Components in Sole Soybean and Soybean/Celosia Inter-Crop in Makurdi (Southern Guinea Savanna Ecology), Nigeria

Genetic Variation for Yield and Yield Components in Sole Soybean and Soybean/Celosia Inter-Crop in Makurdi (Southern Guinea Savanna Ecology), Nigeria

Evaluation of genotype x year interaction in extra-early maturing maize hybrids in a typical Southern Guinea Savannah Ecology

In Nigeria, genotype by environment interaction effect on maize grain yield is usually significant due to considerable variation in soil and weather conditions of the growing sites. This also complicates identification and selection of superior genotypes in a particular environment. Consequently a proper understanding of the effects of G x E interactions on varietal evaluation and cultivar recommendations is vital. This study was therefore conducted to evaluate performance of drought tolerant maize hybrids of different maturity groups. The first group comprised twenty-four extraearly yellow and the second comprised seventeen early white QPM hybrids, both obtained from the International Institute of Tropical Agriculture (IITA), Ibadan. The genetic materials were evaluated in replicated trials during the 2012 and 2013 growing seasons at the Teaching and Research Farm, University of Ilorin, in a typical Southern Guinea Savanna ecology of Nigeria. The effects of genotype (G), year (Y) and G × Y were found to be highly significant (P< 0·01) for grain yield in the extra-early yellow hybrids (EEYH) while among the early white QPM hybrids, genotypic (G) effect was significant only for days to silk and plant height. G x Y interactive effect was however significant only for days to silking. Hybrids EEYH 5, EEYH-27 and EWQH-3 were consistent among the top 5 ranking genotypes for both years in terms of grain yield, an indication for stability to this ecology. Correlation between grain yield and associated traits showed that ears per plant and plant height contributed significantly to grain yield in both groups. Regression analysis of grain yield and other associated traits also revealed that ears per plant contributed significantly to grain yield in extra early yellow hybrids while plant height contributed significantly in the early white QPM hybrids. Therefore, selection programme should give attention to ears per plant and plant height in the varieties intended for drought prone ecology of the Southern Guinea Savanna of Nigeria. Keywords: Genotype, Maize, Hybrids Early-maturing, Extral-early maturing

Influence of water depth and seedling rate on the performance of late season lowland rice (Oryza sativa L) in a Southern Guinea Savanna ecology of Nigeria

A three year field experiment was conducted between 2010 and 2012 at the irrigated lowland experimental field of National Cereals Research Institute in Edozhigi (9°04N, 6°7E) of the Southern Guinea savannah ecological zone of Nigeria, to determine the effect of different water depths and seedling rates on yield and yield components of lowland rice. The trial was laid out in a split plot and arranged in a randomized complete block design by six regimes of water depths (5 cm, 10 cm, 15 cm, 20 cm, saturated soil and continuous flow of water at 2 cm depth) was accommodated in the main plot while the seedling rate of 2, 4 and 6 per stand constituted the sub-plots. The results indicated that both grain yield and yield components of rice were enhanced while the water level increased to 20 cm, although both tiller and height were negatively affected by higher water level at the early stage of growth but it was later compensated at later stage. Water depth of 15 - 20 cm revealed higher grain yield of 5051.8, 4700.4 and 4066.0 kg ha-1 which was 84.4%, 85.2% and 84.7% higher than yields obtained from saturated plot in 2010, 2011 and 2012 respectively. Rice yield and yield components were significantly affected by different seedling rates and six seedlings per stand gave grain yield that is 13.1%, 27.8% and 14.4% higher than 2 seedling rate in 2010, 2011 and 2012, respectively. It is therefore concluded that maintaining water depth between 15 to 20 cm and seedling rate of 4 to 6 enhanced yield and yield components of lowland rice

Comparative Evaluation of Water Deficit Tolerance Capacity of Extra-early and Early Maize Genotypes under Controlled Conditions

Maize is an important staple food crop in Tropical Africa including Nigeria. However, the production of the crop is constrained by inadequate soil moisture resulting from erratic rainfall distribution. There is therefore the need to breed and select for drought tolerant genotypes for production especially in the southern Guinea savannah ecology responsible for over 60% of maize production in Nigeria. Controlled experiments using potted plants were therefore conducted during the dry periods between November 2007 and April 2008. The study evaluated moisture deficit tolerance capacity of two maize maturity groups, consisting of 15 extra-early and 12 early genotypes along with two local checks, subjected to two moisture levels 25% (stressed) and 100% (unstressed) soil available moisture) determined gravimetrically. Crop establishment parameters (% germination and mean germination time (MGT), morphological growth parameters (number and area of leaves, plant height, flowering characteristics), physiological growth indices (leaf area index, crop growth rate, relative growth rate, net assimilation rate and leaf area ratio) were measured during growth. Yield components (harvest index, shelling percentage and number of kernels per cob) and grain yield were determined at harvest. The data were analyzed using the general model of ANOVA and significant means were separated by the Least Significance Difference (LSD) at 5% probability level. The results showed that there were no appreciable differences between the two maturity groups for most measured parameters. However, across the two groups, crop establishment parameters, morpho-physiological growth parameters, yield components and grain yield were significantly reduced by soil moisture deficit, while flowering characteristics were significantly delayed by soil moisture stress with significant variable genotypic responses. Grain yield reduction due to water stress was significantly related to drought susceptibility index (DSI) of the genotypes in the two maturity groups. Conclusively, whereas extra-early genotypes showed good yield potentials but poor drought tolerance which suggested poor yield stability and therefore may not be suitable for the southern Guinea savanna (SGS) ecology in the event of severe stress. However, early genotypes, though showed lower yield potential, had good yield stability and hence are promising genotypes for the SGS ecology.

Evaluation of new generations of maize streak virus (msv) resistant varieties for grain yield, agronomic potential and adaptation to a southern guinea savanna ecology of Nigeria

Five new generations of maize streak virus (MSV) resistant varieties were evaluated along with two checks in replicated trials and for two years in a southern guinea savanna ecology of Nigeria, which is an endemic zone for the disease. Difference in grain yield between favourable growing season in 2002 and unfavourable season in 2001 was 1.68 t/ha-1, representing 30.2% yield increase of 2001 performance. Results further showed that while both rust and streak diseases appeared to have been put in check, the genotypes showed slight susceptibility to leaf blight and curvularia leaf spot, ranging from 5-7 and 4-8 percent (%) respectively. Genotypic differences were significant for grain yield, agronomic traits as well as incidences of leaf blight and curvularia leaf spot. Acr 91 Suwan-1- SR C1 was the most productive of new generations of MSV resistant varieties, having yielded significantly higher than OPV check by 32 percent (%) and comparable with the hybrid check for grain yield. The variety could therefore serve as replacement to existing cultivar and also as source of genes for future maize breeding activities in the development of superior maize varieties for the southern guinea savanna ecology. Key words: Genotypes, grain yield, leaf diseases, adaptation.

Evaluation of new generation maize steak virus (MSV) resistant maize varieties for adaptation to a southern guinea savanna ecology of Nigeria

Five new generations of maize streak virus (MSV) resistant varieties were evaluated along with two checks in replicated trials and for two years in a Southern Guinea Savanna Ecology of Nigeria, which is an endemic zone for the disease. Difference in grain yield between favourable growing season in 2002 and unfavourable season in 2001 was 1.68 t/ha-1, representing 30.2% yield increase of 2001 performance. Results further showed that while both rust and streak diseases appeared to have been put in check, the genotypes showed slight susceptibility to leaf blight and curvularia leaf spot, ranging from 5-7 and 4-8%, respectively. Genotypic differences were significant for grain yield, agronomic traits as well as incidences of leaf blight and curvularia leaf spot. Acr 91 Suwan-1-SR C1 was the most productive of new generations of MSV resistant varieties, having yielded significantly higher than OPV check by 32% and comparable with the hybrid check for grain yield. The variety could therefore serve as replacement to existing cultivar and also as source of genes for future maize breeding activities in the development of superior maize varieties for the southern guinea savanna ecology.

Evaluation of soybean [Glycine max (L) Merrill] genotypes for adaptability to a southern Guinea savanna environment with and without P fertilizer application in north central Nigeria.

Cultivar evaluation is essential to ascertain the superiority of the newly developed genotypes over the established cultivars in terms of yield and adaptation to an ecology. Field experiments were conducted to evaluate some of the recently developed soybean genotypes with and without P fertilizer application for adaptability to southern Guinea savanna ecology of Nigeria. The study was carried out at the experimental field of the Teaching and Research Farm, University of Ilorin, Nigeria, during the 2003 and 2004 cropping seasons. Application of 30 kg P ha-1 resulted in significantly higher growth and grain yield parameters compared to no P application. Grain yield was consistently significantly higher for TGX 1448-2E than for other genotypes including the established cultivar, TGX 923-2E over the two cropping seasons. Significant year x genotype effect indicated that grain yields were significantly different between the two cropping seasons for TGX 1830-20E, TGX 1740-2F and TGX 1871-12E in 2004, while there was no significant variation for grain yield for TGX 1448-2E, TGX 1844-18E and TGX 1869-31E for the two years. This suggests stable grain yields in the latter genotypes and hence good adaptability, while the former ones showed unstable productivity under adverse soil moisture condition resulting from lower rainfall in 2003, and thus were deemed unsuitable for the southern Guinea savanna ecology which is highly prone to drought conditions. Simple linear regression analysis revealed that number of pods per plant was the most important factor influencing grain yield in this study. In conclusion, TGX 1448-2E was the genotype best adapted genotype to the southern Guinea savanna ecology and thus it can successfully replace TGX 923-2E the existing cultivar. Nevertheless, TGX 1844-18E and TGX 1869-31E are promising as drought tolerant genotypes. Key words: Adaptability, southern Guinea savanna ecology, new soybean genotype, P fertilizer application.

Combining ability for maize grain yield and other agronomic characters in a typical southern guinea savanna ecology of Nigeria

Field experiments were conducted at the University of Ilorin Teaching and Research Farm in 2005 and 2006 cropping seasons with the objective to evaluate the combining ability for maize grain yield and other agronomic characters in 10 open pollinated maize varieties, which have been selected for high yield and stress tolerance. General combining ability (gca) and year (y) effects were significant for all the parameters except plant height, while specific combining ability (sca) and gca x year effects were significant only for grain yield. However, Tze Comp4 Dmr Srbc2, Tze Comp4 C2 and Acr 94 Tze Comp5 which are good general combiners for maize grain yield, also showed positive significant gca x year effects for flowering traits. Significant sca x year interaction effects were recorded for maize grain yield and days to flowering, with Hei 97 Tze Comp3 C4 combining very well with 3 parents (Acr 90 Pool 16-Dt, Tze Comp4-Dmr Srbc2 and Tze Comp4 C2). These parents and their hybrids probably have genes that can be introgressed into other promising lines in developing early maturing and high yielding varieties for cultivation in the Nigeria savannas.

Combining ability for maize grain yield and other agronomic characters in a typical southern guinea savanna ecology of Nigeria

Field experiments were conducted at the University of Ilorin Teaching and Research Farm in 2005 and 2006 cropping seasons with the objective to evaluate the combining ability for maize grain yield and other agronomic characters in 10 open pollinated maize varieties, which have been selected for high yield and stress tolerance. General combining ability (gca) and year (y) effects were significant for all the parameters except plant height, while specific combining ability (sca) and gca x year effects were significant only for grain yield. However, Tze Comp4 Dmr Srbc2, Tze Comp4 C2 and Acr 94 Tze Comp5 which are good general combiners for maize grain yield, also showed positive significant gca x year effects for flowering traits. Significant sca x year interaction effects were recorded for maize grain yield and days to flowering, with Hei 97 Tze Comp3 C4 combining very well with 3 parents (Acr 90 Pool 16-Dt, Tze Comp4-Dmr Srbc2 and Tze Comp4 C2). These parents and their hybrids probably have genes that can be introgressed into other promising lines in developing early maturing and high yielding varieties for cultivation in the Nigeria savannas. Key words: Zea mays L., general combining ability, specific combining ability, grain yield, Nigeria savannas.

Assessment of grain yield and nitrogen use, efficiency in extra-early maize (Zea mays L.) varieties and their top cross hybrids under low N-fertilizer regimes in a typical Southern Guinea savanna ecology of Nigeria

Assessment of maize (Zea mays L.) nitrogen (N) fertilizer requirements under low input farming system is necessary in order to develop maize production packages that will be compatible with resource poor farmers’ need. Nine extra-early maize varieties and their top cross hybrids derived by intercrossing unto a local variety (AFO) as the pollen parent were evaluated at the Teaching and Research (T&R) Farm of the University of Ilorin in a typical Southern Guinea Savanna (SGS) ecology of Nigeria, using five N-fertilizer levels (0, 20, 40, 60 & 80 kg Nha-1 respectively). The objectives were to assess the performance of the genotypes for grain yield and nitrogen use efficiency (NUE) and also identify productive maize genotypes under low N-fertilizer regime consistent with farmers’ practice in the SGS zone. Grain yield and NUE differed significantly (P< 0.05 or 0.01) each season (S) with a difference of 0.27t/ha-1 in grain yield between 1998 full growing season and 1999 late season but with a corresponding delay of 2 days in mid-silk in the varieties per se. Conversely, the expression of the two traits in the hybrids was similar in the two growing seasons of 1999. Grain yield increased with increase in N-dosage in both varieties and hybrids but was higher in the varieties per se relative to the hybrids while NUE showed no consistent trend at increasing N-levels except at 60 kg Nha-1. However, the capacity to utilize N as measured by NUE was optimum at 40kg Nha-1 in both varieties and hybrids. Differences in grain yield between 0 and 80 kg Nha-1 were 1.07 and 1.34 t/ha-1 respectively in both varieties and hybrids. Genotypic (G) effects differed (P< 0.01) for grain yield. NUE and other traits in the varieties per se while the hybrids also differed for these characters except NUE and ear height. The first order interaction of S x N was significant for both grain yield and NUE in both varieties and hybrids while G x S effect was non-significant for both characters. Grain yield correlated positively and significantly with growth morphological and flowering traits in the varieties per se, while NUE correlated positively and significantly only with seedling height, plant and ear heights as well as harvestable ears and grain yield. Var CSP-SR x TZE Y and its hybrid (CSP-SR x TZE y) x AFO combined high grain yield with superior for NUE. This indicates that the variety can be further tested under farmer’s conditions and can also be a source of inbred line extraction for developing N-stress tolerant varieties. JARD Vol. 5 (2) 2006: pp. 112-128

Evaluation of short duration maize (&lt;i&gt;Zea mays&lt;/i&gt; L) varieties for adaptation to a typical Southern guinea savanna ecology of Nigeria

The Southern Guinea Savanna (SGS) of Nigeria is yet to attain its potential for maize production primarily due to lack of information on productive maize genotypes that could fit into the erratic rainfall pattern in the ecology. Adoption of improved short duration maize genotypes intended for cultivation in marginal and drought-prone ecologies would boost maize production beyond its present level. As a preliminary step towards facilitating the adoption of such maize genotypes, 28 maize varieties belonging to two different maturity groups were evaluated in a replicated trial for three seasons at Ilorin in a typical SGS ecology. Significant genotypic differences (P

Field evaluation soybean varieties at Ilorin in the southern guinea savanna ecology of Nigeria

Twenty six newly developed soybean varieties were evaluated for two years at Ilorin in a southern guinea savanna environment of Nigeria. The reaction of the varieties to rust infection was also assessed. Effects due to year, variety and year x variety interaction were significant for all the characters evaluated except for plant height where year x variety interaction had no significant effect. Number of days to 50% flowering ranged from 42 to 47.33. Early flowering varieties included TGX 1903-8F, TGX 1903-7F and TGX 1904-2F, while late flowering ones were TGX 1924-1F and TGX 1925-1F. Plant height varied between 25.00 and 44.17 cm. Grain yield ranged from 1017.24 to 2133.01 kg/ha. The best yielding varieties were TGX 1921-23F and TGX 1922-1F. Significantly higher grain yields were obtained in 2005 with an average value of 1602.0 kg/ha compared with 1470.13 kg/ha recorded in 2006. There was no incidence of rust infection in 2005, but in 2006 however, six soybean varieties expressed mild symptoms of the disease. Key words: Grain yield, varietal evaluation, rust infection, savanna agro-ecology, soybean.

Response of cassava genotypes to four biotic constraints in three agro-ecologies of Nigeria

(Received 13 February, 2001; accepted 14 November, 2001) Abstract Eight improved cassava (Manihot esculenta Crantz) genotypes and one local variety were grown over three years in three agro-ecological zones of Nigeria, to study their response to natural infestations of African cassava mosaic disease (ACMD), cassava bacterial blight (CBB), cassava anthracnose disease (CAD) and cassava green mite (CGM). Additionally, genotypes with stable resistance using the Additive Main Effects and Multiplicative Interaction (AMMI) statistical model was identified. Environments, genotypes and genotype x environment (G x E) interactions were highly significant (P < 0.0001) for the pests, implying that the G x E effects were sufficiently high to mask differences among genotypes. The local variety, TME1, was more tolerant (30% severity) to cassava green mite across sites, compared to other clones, while clone 30001 exhibited the highest susceptibility to the pest (54%). Genotypes (30001, TME1 and 30573) gave lowest severity scores for ACMD. Clones used in the study, especially U/41044, 4(2) 1425 and 63397, showed tolerance to CBB and CAD with severity ratings as low as 2.0. Across test sites, CGM had the highest severity scores (3.12) averaged over 3 years in Ilorin (in the Southern Guinea savanna ecology). The lowest severity scores of this disease were observed in Ubiaja and Onne. The severity of ACMD and CBB was highest in Ibadan and Ubiaja and lowest in Onne and Owerri. Cassava anthracnose disease was more severe in Ibadan (score of 2.5) and least severe in Mokwa (1.12). For CGM the highest severity was recorded in the Southern Guinea savanna (score 2.88) and lowest in the humid forest zone. Correlation coefficients calculated between pairs of biotic constraints revealed that cassava bacterial blight was negatively correlated (r=-0.78) with the green mite but positively correlated with anthracnose disease (r=0.94). The AMMI model selected AMM11 for CGM and CBB, and AMM14 and AMM13 for ACMD and CAD, respectively, as the best predictive models since these models had the smallest actual root mean square prediction differences (0.60598 and 0.37646 for CGM and CBB, respectively and 0.37297; and 0.40929 for ACMD and CAD, respectively. Genotypes 30572, 63397, 50395 and 4(2)1425 with low ACMD scores and low IPCA1 scores were the most stable to environmental changes as they combined resistance with stability of response. Such genotypes would be most appropriate in breeding programmes. Key Words: African cassava, anthracnose, bacterial blight, green mite, mosaic disease Résumé Un essai a été mené sur huit clones améliorés de génotypes de manioc et une variété locale, dans trois zones agro-écologiques du Nigéria, pour étudier leur comportement à la mosaïque, bactériose, anthracnose et acarien vert du manioc. L'étude s'était étalée sur une période de plus de trois ans. Additionnellement, les génotypes à résistance stable étaient identifiés en utilisant la méthode statistique des effets principaux additifs et intéractions multiplicatives. Les effets de l'environnement, du génotype et l'intéraction génotype et l'environnement (GXE) étaient significativement élévées (P