Open Pollinated Maize Varieties Research Articles

Sustainable urban agriculture using compost and an open-pollinated maize variety

Global urbanization leads to the loss of periurban farming land and increases dependency on distant agriculture systems. This provokes greenhouse gas emissions associated with transportation and storage while disconnecting nutrient cycles, as urban organic waste is not recycled into the agricultural system. Urban food production based on composted local biomass could reduce these problems, but currently used hybrid crops rely strongly on inorganic fertilizers. On the contrary, open-pollinated varieties were bred for productivity under organic fertilization, such as compost. Hypothesising that open-pollinated varieties retain high nutritional value under low nutrient conditions, a commercial hybrid and a local open-pollinated variety of maize were cultivated in non-fertilized soil and under two compost applications: Municipal compost as high nutrient input or locally produced green waste compost and municipal compost mix, as medium nutrient input. Unfertilized plots exhibited low grain production (1.9 t/ha), but yields under green waste compost/municipal compost (6.1 t/ha) and municipal compost (7.8 t/ha) treatments were comparable to observations from maize under inorganic fertilization. Contrary to the commercial variety, the open-pollinated variety exhibited higher grain micronutrient concentrations, e.g. 220% higher zinc concentrations and lower accumulation of heavy metals, e.g. 74% lower nickel concentrations. This variety-related effect was found in all treatments and was independent of soil micronutrient concentrations. In conclusion, both compost mixes were effective in increasing grain yield in both maize varieties. However, the open-pollinated variety produced grain with higher nutritional values in soil and all treatments, indicating it is potentially better suited for compost-based sustainable urban agriculture.

Optimizing Sample Size for Molecular Characterization of Open-pollinated Maize (Zea Mays L.) Varieties Using Simple Sequence Repeat Markers

Molecular-based characterization of open-pollinated varieties (OPVs) in maize is useful to define their unique profiles. A total of 58 SSR markers selected from a panel of 70 were used for genotyping three samples of 30, 50 and 100 plant bulks for each of 32 OPVs. The SSR markers detected a total of 253 alleles in the 32 maize OPVs across the three bulk samples. The number of alleles per marker varied from 2 to 7, with an overall mean of 4.36. The genetic distance among the OPVs varied from 0.17 to 0.93 with an average of 0.70 ± 0.007 for bulk samples of 30 plants, 0.20 to 0.91 with an overall mean of 0.70 ± 0.007 for bulk samples of 50 plants and from 0.30 to 0.95 with an average of 0.75 ± 0.006 for bulk samples of 100 plants. Cluster analysis separated the 32 maize OPVs into two major groups, which were further separated into two sub-groups for each type of bulk sample. The groupings of the OPVs into two major groups and their corresponding sub-groups was consistent with known breeding history (common parentage) and common target traits during development of the OPVs irrespective of the sample size used. However, in the bulk samples of 50 and 100 plants, some sub-groups were composed of OPVs with mixed maturity classes and diverse genetic backgrounds. Of the three independent bulk samples, the smallest sample size of 30 plants was found to be optimal for characterizing heterogeneous and heterozygous maize populations and OPVs owing to its cost-effectiveness and relative ease of sample processing.

Combining Ability and Heterosis of Tolerance to Low Soil Nitrogen in Tropical Maize Cultivars Derived from Two Breeding Eras

Abstract Low soil nitrogen is one of the principal abiotic stresses affecting maize productivity in Sub-saharan Africa. Field studies were conducted at the International Institute of Tropical Agriculture (IITA), Ibadan during the cropping seasons for three years, from 2010 to 2012, with ten open pollinated maize varieties (OPVs) derived from two breeding eras (1 and 2). The ten OPVs and their crosses were evaluated under high-N and low-N conditions. The aim was to identify superior populations that may be useful sources genes for inbred line extraction and hybrid development for grain yield. Under low-N condition, mid and high parent heterosis for grain yield were low indicating the suitability of the hybrids for cultivation only in environments with high productivity index. Hybrid DMR-LSR-W (Era 1) × TZSR-Y-I (Era 2) had greatest mid and high-parent heterosis for grain yield under high-N and across the other four test environments. Parent AMATZBR-WC2B with higher general combining ability effects and mean values for grain yield, and cross combinations DMR-LSR-W (Era 1) x BR9928DMRSR (Era 2) and BR9922DMRSR (Era 2) x TZBRELD-4C0W (Era 2) with higher specific combining ability for grain yield under low-N environment are promising candidates for the development of nitrogen use efficient varieties for cultivation in low-N environments.

Back to beaked: Zea mays subsp. mays Rostrata Group in northern Italy, refugia and revival of open-pollinated maize landraces in an intensive cropping system.

Crop landraces are fundamental resources to increase the eroded genepool of modern crops in order to adapt agriculture to future challenges; plus, they are of immeasurable heritage and cultural value. Between the 1940s and the 1960s open-pollinated varieties (OPVs) of flint and semi-flint maize in Europe were almost completely replaced by high-yielding hybrid dent cultivars selected in North America. No comprehensive assessment was performed after the 1950s to understand which maize genetic resources survived genetic erosion in northern Italy, an area characterized by a high degree of landraces extinction and introgression, intensive hybrid dent monocultures, as well as being one of the hotspots of maize cultivation at a continental level. Among these landraces, beaked maize represents a peculiar case study for assessing the survival of OPVs in intensive cropping systems. By means of ethnobotanical and literature surveys, the history of Zea mays subsp. mays Rostrata Group and its current distribution were reconstructed. It emerged that beaked maize originated in the study area and it is one of the oldest genepools available not subjected to formal crop improvement. We identified 28 landraces of beaked maize currently cultivated, 18 here recorded for the first time. The cultivation of more than half of the 28 landraces has continued throughout the last 80 years in a few fragmented localities that can be regarded as “refugia”. The survival of these landraces from substitution with high-yielding cultivars and unidirectional introgression has been mainly due to active on-farm conservation performed by custodian farmers and secondarily to cultivation in isolated areas (e.g., mountain valleys). After decades of genetic erosion, beaked maize has since the late 1990s experienced a revival, in terms of an increasing number of cultivation localities and the level of product commercialization. This process is mostly spontaneous and only occasionally mediated by governmental institutions; it is linked to the rediscovery of local food products, in this case mainly polenta, a dish made of corn flour, which used to be the staple food across northern Italy. The ex situ conservation of beaked maize and on-farm measures put in place by the farmers to prevent introgression are also assessed. Further research and collecting missions are needed to provide an inventory of open-pollinated landraces of other landrace groups that have survived genetic erosion in Europe. To meet this aim, extensive ethnobotanical surveys, such as the one performed here, are very powerful tools in detecting these genetic resources.

Three New Maize Hybrids for Afghanistan

Afghanistan grows maize in about 0.15 m ha with an annual production hovering around 300,000 tonnes. The country does not have any officially released commercial maize hybrid and relies only on open pollinated varieties for cultivating maize. The countries in region enjoy much higher productivity levels ranging from 3.5 to 5.00 tonnes per ha compared to 2.2 tonnes per ha of Afghanistan. Several maize hybrids were introduced from CIMMYT to test them for adaptation and yielding ability in Afghanistan for the purpose of releasing them in the country. The three public sector maize hybrids described in this communication were tested at several locations viz., Nangarhar province, Kabul, Baghlan and Helmand in Afghanistan during 2012 to 2014 crop seasons. The hybrids/inbreds bred by CIMMYT were tested against the currently grown open pollinated (OP) varieties and they yielded on an average 31 to 38% higher than the currently popular open pollinated maize varieties. The hybrids were released for commercial cultivation in 2014.

Genetic Dissection of Low-N Traits using Triple Test Cross Analysis in Maize (Zea mays L.)

Low-N maize is bred for its ability to tolerate low soil nitrogen (N) by growing and producing grain that compares appreciably to conventional varieties. This experiment was conducted to study the genetic effects of grain yield and other agronomic traits in Low-N maize using triple test cross analysis. Twelve low-N open pollinated maize varieties were converted to the inbred line after six generations of selfing and used for the experiment. Two inbred lines along with their F1 were used as testers for ten inbred lines in a triple test cross pattern to generate 30 crosses and along with their parents and testers to make a total of 43 entries which were evaluated at the Teaching and Research Farms of Ekiti State University, Ado-Ekiti during in 2017. The design was a Randomized Complete Block Design (RCBD). Data was collected on plant height, ear height, days to 50% anthesis, days to 50% silking, the incidence of Curvularia leaf spot, blight, plant aspect, ear aspect, ear rot, stay green, cob per plant, ear weight, grain moisture content and grain yield. All data was subjected to analysis of variance and complete genetic estimates made. Additive and dominants were significant (P0.05) for all traits, however, epitasis estimates were not significant for all the traits. The degree of dominance component indicated partial dominance for all the traits. Correlation coefficients for days to 50% anthesis and 50% silking, plant height, ear height, number of cob per plant and grain yield were positive and significant (P0.05). Since both additive and dominance gene actions were important for low-N traits, the use of reciprocal recurrent selection procedure can be adopted in incorporating the trait into elite maize varieties.

Conservation agriculture with trees amplifies negative effects of reduced tillage on maize performance in East Africa

Conservation agriculture (CA) is widely promoted in sub-Saharan Africa both in open fields and in agroforestry where the practice is known as ‘conservation agriculture with trees’ (CAWT). Although advantages and disadvantages of CA are well studied under sole cropping, less is known about its impact in agroforestry systems. The performance of open pollinated maize varieties under CA, CAWT, sole maize under conventional tillage (CT) and conventional tillage with trees (CTWT) was compared on-farm in equatorial savannah areas over four consecutive seasons in Rwanda and two seasons in Ethiopia. The tree species considered in the study were mature Grevillea robusta (A. Cunn.) and Senna spectabilis (DC.) in Rwanda and mature Acacia tortilis (Forssk.) in Ethiopia. Both CA and the presence of trees consistently reduced maize emergence, leaf area (LA), plant height, and maize yields. Crop emergence was significantly reduced under CAWT compared with CTWT. Maize emergence rates in CAWT and CTWT were respectively 46.9% and 70.1%, compared with 74.7% and 79.8% in sole maize under CA and CT. Grain yield in CAWT and CTWT were respectively 0.37 t dry matter (DM) ha−1 and 1.18 t DM ha−1 as compared with 1.65 t DM ha−1 and 1.95 t DM ha−1 in CA and CT. We conclude that CAWT strongly reduces crop yield in the equatorial savannah of East Africa. CA is incompatible with agroforestry under the conditions of our study. There is an urgent need for rigorous research to revisit if, when and where CAWT can generate benefits for smallholder farmers.

Phenotyping open-pollinated maize varieties for environments with low nitrogen availability

ABSTRACTThe high nitrogen nutrient requirement of maize is a major production constraint in areas that have a low availability of soil nitrogen. A 2-year field experiment was conducted to characterize open-pollinated varieties of maize by identifying possible sources of variability targeting low N environments. Twelve experimental varieties and two checks, AL Avaré and Ipanema, were cultivated under high and low nitrogen levels and evaluated for chlorophyll content index, lodging, prolificacy and grain yield. The results indicate that the applied nitrogen resulted in differences in the chlorophyll content index between environments. Nitrogen level affected the percentage of lodged plants of varieties K and L. Grain yield and lodging were the traits that most affected genotypic variability, and 17% of the studied varieties were considered as superior due to higher lodging-resistance and higher grain yield.

Determining the Heterotic Group of the Nineteen Open Pollinated Maize Varieties from Their Topcrosses with Inbreed Line Testers in Uganda

Determining the Heterotic Group of the Nineteen Open Pollinated Maize Varieties from Their Topcrosses with Inbreed Line Testers in Uganda

Quantifying Variability in Maize Yield Response to Nutrient Applications in the Northern Nigerian Savanna

Diagnostic on-farm nutrient omission trials were conducted over two cropping seasons (2015 and 2016) to assess soil nutrients related constraints to maize yield in the northern Nigerian savanna agro-ecological zone and to quantify their variability. Two sets of trials were conducted side by side, one with an open pollinated maize variety (OPV) and the other one with a hybrid maize variety and each set had six equal treatments laid out in 198 farmers’ fields. The treatments comprised (i) a control, (ii) a PK (‘−N,’ without N), (iii) an NK (‘−P,’ without P), (iv) an NP (‘−K,’ without K), (v) an NPK and (vi) an NPK + S + Ca + Mg + Zn + B (‘+SMM,’ NPK plus secondary macro- and micro-nutrients). Moderate to a large variability in most soil characteristics was observed in the studied fields. Consequently, cluster analysis revealed three distinct yield-nutrient response classes common for the two types of maize varieties. These define classes were fields that have (i) no-response to any nutrient, (ii) a large response to N and P and (iii) a large response to N alone. Although overall yield performance of OPV and hybrid varieties was similar, a distinct fourth class was identified for the hybrid variety, (iv) fields with a large response to N and secondary macro- and micro-nutrients. The results indicate that the large variability in soil nutrients related constraints need to be accounted for to optimize maize yield in the northern Nigerian savanna. The development of field- and area-specific fertilizer recommendations is highly needed, using simple decision support tools that consider variable soil fertility conditions and yield responses as obtained from this study.

Bioactive compounds of freshly harvested open pollinated varieties (OPV) of orange maize (zea mays): Varietal, maturity, and boiling methods effects

Biofortified open pollinated maize varieties (OPV) could be used to address the problem of micronutrient deficiencies in developing countries. This study aimed at investigating the effects of matur...

Direct and indirect effects of cob traits on yield in exotic maize germplasm under nitrogen deficient conditions

Despite of adoption of hybrid maize cultivation to a considerable level, maize yields in Pakistan are lower than other countries in the region. With others, maize cultivation under low soil fertility and without supplemental nitrogenous inputs is an important reason for low yields. This derives national maize breeding programs to develop low-nitrogen responsive maize cultivars. In this context, exotic maize open-pollinated varieties were introduced from CIMMYT for adaptability testing and subsequent adaptation. The trial including these OPVs was planted under zero nitrogen application. Correlation and path coefficient analysis was used to establish association of grain yield with its components to ascertain specific selection criteria which will be used to enhance efficiency of the future maize breeding and yield improvement programs using this germplasm. The results complemented with heritability estimates revealed that 100-kernel weight and shelling percentage together with kernel rows per cob can be utilized effectively for yield enhancement under nitrogen deficient conditions. Keywords: Correlation; Low nitrogen; Maize; Path analysis; Yield http://dx.doi.org/10.19045/bspab.2017.600116

HETEROSIS OF SOME TROPICAL MAIZE GENOTYPES DERIVED FROM TWO DIFFERENT MAIZE BREEDING ERAS

Heterosis for maize grain yield was studied to identify cross combinations that may be useful sources for inbred line extraction, recurrent selection and, to estimate changes in the maize grain yield heterosis across two breeding eras in the tropics. Field studies were conducted at the International Institute of Tropical Agriculture (IITA), Ibadan during the cropping seasons of 2010, 2011 and 2012, with 10 open pollinated maize varieties (OPVs) derived two breeding eras (1 and 2). The ten OPVs and the crosses generated from them were evaluated under stem borer infested and non-infested, high-N versus low-N and natural conditions. Mid and High-heterosis (MPH & HPH) were estimated from grain yield data from the tested environments. MPH & HPH under natural, optimum N-Fertilizer application, and borer infested environments were 37.20 and 25.38%, 19.85 and 12.3%, 30.98 and 18.94% respectively. Cross combination DMR-LSR-W (Era 1) x TZSR-Y-I (Era 1) expressed the highest magnitude of (MPH & HPH) (97.70 and 87.15%) for grain yield across the tested environments except low-N. It suggest the suitability of the hybrid for cultivation only in environments with high productivity index. Hybrid ACR99TZLCOMP4-DMRSR (Era 1) x BR9928DMRSR (Era 2) had highest HPH under low-N environments. Suggesting this combination as a good source of genes for the development of low nitrogen tolerance maize varieties in the tropics. Cross combinations that expressed better (HPH) under borer infestation are good gene pools for the development of stem borer tolerance maize varieties in stem borer endemic zone. These crosses hold promise as future candidates for commercial exploitation of heterosis or for the extraction of inbred lines in the tropics. Better (HPH) were derived from the crosses between Era 1 and & 2, indicates the older and newer maize varieties complement each other for (HPH) across environments.

Ex-situ conservation of maize germplasm from different latitudes

Germplasm collections often include open-pollinated varieties from diverse latitudes and climatic areas that cannot be correctly conserved in a single environment. The objective of this research was to investigate if open-pollinated maize varieties from diverse latitudinal and climatic conditions could be conserved in a single location. Twelve varieties from the humid Spain, the dry Spain, and the Canary Island were multiplied in three locations from the humid Spain, one from the dry Spain, and one from the Canary Islands. Hand pollinations were made in 100-plant plots following a randomized complete block design with two replications in five locations during two years. Differences between origins and between varieties were significant for most traits, including those related to growth cycle (male and female flowering and grain moisture). The varieties from each latitudinal and climatic origin did not behave as a consistent germplasm block; contrarily, the location × variety interaction was significant for most traits. The varieties from the humid Spain maintained their ranks of growth cycle across locations and differences between varieties were more important in the dry Spain. The growth cycle of the Canarian varieties was completely different in the dry Spain. We can maintain the varieties from any Spanish environment and latitude at any location, but most varieties could be modified by natural selection for adaptation.

The study of open-pollinated maize variety under non-irrigated condition

Maize is the one of the world leading crop. 90% of the maize produced in industrialized countries is grown in temperate production environments which mean that Mongolia has potential to grow maize plant. Three open-pollinated varieties (OPV) were studied in Institute of Plant and Agricultural Sciences to compare growing potential under non-irrigated condition. Mongolian corn population showed high significance than the other two on yield related traits, ear length, kernel length, fresh ear weight, tassel length and number of kernel per row. The result showed that studied OPV can yield under rain-fed condition and can be distributed to the farmers.

Evaluating Adaptability and Yield Performance of Open Pollinated Maize Varieties in North Western Tigray

In order to evaluate the performance of improved maize genotypes, an experiment was conducted at Medebay zana and Laelay Adiabo district of North western of Tigray, Ethiopia, during 2014 and 2015 main cropping season. The experiment was laid out in a randomized complete block design with three replications. The data were recorded on plant height, ear height, number of ears/plot, plant and ear height, days to 50% anthesis, silking, maturity, grain yield and 1000 grain weight. All varieties showed significant differences with each other for all the traits studied in most environments but incase of genotype by environment combined data revealed most of the traits gave nonsignificant result and indicated better to focus and recommend on the stable genotypes across the environments. Variety Gibe-2 and Gibe-1 had the top two highest grain yield of 5114.15 kg ha-1 and 4964.96 kg ha-1. Melkasa-6 was the early maturing variety as compared with standard checks of melkasa-2 and the remained varieties. The highest plant height and ear placement of 237.28, 120.80, respectively cm was noted in variety Gibe-1. This variety may be susceptible to lodging. These varieties had a wide genetic background, thus showing grain yield ranges from 1748 to 5114 kg ha-1. So, generally maize variety of Gibe-1 and Gibe-2 were found most promising, which has the potential to increase the average yield of maize in Medebay zana and Laelay Adiabo districts and is therefore recommended to demonstrate for general cultivation in both districts.

Fertilizers, hybrids, and the sustainable intensification of maize systems in the rainfed mid-hills of Nepal

Abstract In the rainfed mid-hill region of Nepal, most fields receive 2–3 t ha−1 of organic compost application every year. Despite efficient recovery and use of organics in the mixed crop-animal systems that predominant in the mid-hills, depleted soil fertility is widely understood to be a significant constraint to crop productivity, with most farmers achieving maize grain yields below 2 t ha−1. Increased use of fertilizer may arrest and even reverse long-term soil quality degradation, but few farmers in the mid-hills use them at present and existing recommendations are insufficiently responsive to site, varietal, and management factors that influence the productivity and profitability of increased fertilizer use. Moreover, policy makers and development practitioners often hold the perception that returns to fertilizer use in the mid-hills are too low to merit investment. In this study, on-farm experiments were conducted at 16 sites in the Palpa district, Nepal to assess the responsiveness of a maize hybrid (DKC 9081) and an ‘improved’ open-pollinated maize variety (‘OPV’, Manakamana-3) to four nitrogen (N) rates, i.e., 0, 60, 120 and 180 kg ha−1, with each N rate response evaluated at 30:30 and 60:60 kg ha−1 rates of phosphorus (P2O5) and potassium (K2O), respectively. With sound agronomy and high rates of fertilizer (180:60:60 kg N:P2O5:K2O ha−1), grain yields observed in the field experiments exceeded 8 t ha−1 with hybrids and 6 t ha−1 with OPV. Yield levels were lower for OPV than hybrid at every level of applied N, but both genotypes responded linearly to N with partial factor productivity for N (PFPN) ranging from 14 to 19 for OPV versus 26–30 for hybrid, with improved N efficiencies obtained when P and K rates were significantly higher. Averaged across phosphorus (P) and potassium (K) levels, a $ 1 incremental investment in fertilizer increased the gross margin (GM) by $ 1.70 ha−1 in OPV and by $ 1.83 ha−1 in the hybrid. For the full response of N, requires higher rate of P2O5:K2O and vice-versa and full response to P2O5:K2O does not occur if N is absent. These results suggest that, i) degraded soils in the mid-hills of Nepal respond favorably to macronutrient fertilizers – even at high rates, ii) balanced fertilization is necessary to optimize returns on investments in N but must be weighed against additional costs, iii) OPVs benefit from investments in fertilizer, albeit at a PFPN that is 36–47% lower than for hybrids, and, consequently iv) hybrids are an effective mechanism for achieving a higher return on fertilizer investments, even when modest rates are applied. To extend these findings across years and sites in the mid-hills, crop growth simulations using the CERES-maize model (DSSAT) were conducted for 11 districts with historical weather and representative soils data. Average simulated (hybrid) maize yields with high fertilizer rate (180:60:60 kg N:P2O5:K2O ha−1) ranged from 3.9 t ha−1 to 7.5 t ha−1 across districts, indicating a high disparity in attainable yield potential. By using these values to estimate district-specific attainable yield targets, recommended N fertilizer rates vary between 65 and 208 kg N ha−1, highlighting the importance of developing domain-specific recommendations. Simulations also suggest the potential utility of using weather forecasts in tandem with site and planting date information to adjust fertilizer recommendations on a seasonal basis.

Participatory varietal evaluation of open pollinated maize in Western Amhara, North-west Ethiopia

Open pollinated maize varieties are one of the best options for farmers who cannot afford the cost of hybrids, cultivating maize in low potential environments and cannot pay for inputs such as fertilizers and pesticides. The experiment was conducted to use farmers’ input and feedback on selection of well-adapted, high-yielding, and disease-tolerant maize varieties. Treatments were arranged incompletely randomized block design with three replications. Gibe-1 was better preferred open pollinated maize variety by famers due its cob length, disease tolerance, good husk cover and yield. Gibe-1 provided the highest grain yield in South Achefer (8.8 t ha-1) and the best performing genotype across environments with grain yield of 7.8 t ha-1. Gibe-1 also had a good reaction to common leaf rust and tercicum leaf blight. GGE biplot analysis classified testing environments in to four mega environments and showed high influence of the environment to grain yield with the contribution of variation 59.59% by the environment, 7.25% by the genotype, and 18.38% by interaction. Gibe-1 was identified as the most ideal open pollinated maize variety which produced the highest mean grain yield and was the most stable. Therefore, Gibe-1 is recommended as a potential open pollinated maize variety for Jabitehinan, South Achefer, and similar agro ecologies.

Correlation of Traits Afffecting Grain Yield in Winter Maize (Zea mays L.) Genotypes

The research was conducted under RCBD with three replication to study the inter relationships among traits affecting yield and its affecting character at National Maize Research Programme (NMRP), Rampur, Nepal in 2013. The eleven inbreeds line of maize variety at winter season in 2013 were evaluated for estimation yield and its affecting character. For efficient selection of grain yield, it is necessary to know relation of yield of maize and its morphological traits which are influencing on the grain yield. One of the objectives of this paper was to determine interrelationship between traits and the yields. Correlation coefficients among traits showed that yield was positively and highly significantly related with number of kernel rows per ear (0.788), number of kernels per row(0.571), ear girth(0.516), plant height(0.498), hundreds kernels weights(0.444) and significantly related with other character. .Number of Kernels rows per ear, number of kernels per row, plant height could be the important selection criteria in improving open pollinated maize varieties for high grain yield.Int J Appl Sci Biotechnol, Vol 3(3): 443-445

Agronomic Performance and Genotype × Environment Interaction of Herbicide‐Resistant Maize Varieties in Eastern Africa

ABSTRACTStriga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze severely affect maize (Zea mays L.) production in sub‐Saharan Africa. A single Striga plant produces a large number of seeds that form a bank of viable but dormant seed in the soil until they get a chemical signal from suitable maize host roots. Imidazolinone‐resistant (IR) open‐pollinated maize varieties (OPVs) developed for Striga control were tested in diverse environments in four countries of eastern Africa in 2004. The objective of the study was to assess the agronomic performance of IR maize and genotype × environment interactions (GE) for grain yield (GY) and the number of emerged Striga plants across 17 environments under Striga‐infested and Striga‐free conditions. In the combined analysis of variance across Striga‐infested and Striga‐free locations, mean squares for genotypes and GE were significant for most measured traits. The best IR maize variety (STR‐VE‐216) outyielded the Striga‐tolerant and commercial genotypes by 113 and 89%, respectively, under Striga‐infested conditions. IR OPVs supported significantly fewer emerged Striga plants relative to the check varieties. Under Striga‐free conditions, IR OPVs showed GY advantage over commercial varieties. Under Striga‐infested conditions genotypic variance () was larger than genotype × location variance () for GY and number of emerged Striga plants at 12 wk after planting. The genetic correlations among locations under Striga‐infested conditions were high (0.990), suggesting little GE between most environments used. Cluster analysis of genotypes under Striga‐infested locations revealed two major groups that separated the IR OPVs from the check varieties. The outstanding performance of selected IR OPVs indicates that their use for Striga control would reduce the Striga seed bank while benefiting farmers with high GY.