Reduction In Maize Grain Yield Research Articles

Influence of different population densities of Bambara groundnut intercrop and weeding frequency on maize (<i>Zea mays</i> L.) performance

Effective weed management is essential for enhanced productivity of maize. A two-year field experiment was carried out at the Department of Crop Science Demonstration Farm, University of Calabar, Calabar, Nigeria (4.5-5.20 N, 8.0-8.30 E), in the 2019 and 2020 early planting seasons, to evaluate the influence of three population densities of Bambara groundnut [166,666 plants per hectare(B1), 100,000 plants per hectare (B2), 71,428 plants per hectare (B3)] and four hand weeding frequencies [weedy check (WC), one hand weeding (1HW), two hand weedings (2HW) and a weed free check (WFC)] on the performance of maize. The experiment consisted of three replications fitted into a Randomized Complete Block Design (RCBD). Data gathered on maize vegetative and yield characteristics were analysed using analysis of variance (ANOVA) procedures for RCBD (GenStat® statistical package, version 8.1). Significantly different means were compared at 5 % probability level using the Duncan’s New Multiple Range Test (DNMRT). From the results, maize growth and yield performance were significantly (P<0.05) affected by Bambara groundnut populations and the frequency of weeding. Leaving weeds unchecked all through the cultivation season hampered the vegetative and yield performance of maize, resulting in 47.54 % reduction in maize grain yield, compared with the weeded plots. Conclusively, intercropping maize with Bambara groundnut at 71,428 plants per hectare integrated with two hand weedings at 4 and 8 weeks after sowing (WAS), which optimized maize grain yield (3.87 t/ha on the two-year average) is recommended for farmers in the Calabar humid area and its environs.

Quantifying maize grain yield losses caused by climate change based on extensive field data across China

Climate change can have significant impacts on maize (Zea mays L.) grain yield. In this study, we used extensive multi-year field experimental data (n = 423) across different climatic regions of China to distinguish effects of different climate factors on maize grain yield and mimicking the effect of climate change, in particular, temperature and solar radiation. Across the years and climatic regions, the major driver for the yield difference was found to be the diurnal temperature range (DTR) and accumulated photosynthetically active radiation (PAR). 1 °C decrease in DTR and 100 MJ decrease in accumulated PAR resulted in 1.0 t ha−1 and 0.85 t ha−1 reduction in maize grain yield, respectively. 1 °C increase in growing season mean temperature (Tmean) and minimum temperature (Tmin) resulted in 0.83 t ha−1 and 0.67 t ha−1 maize grain yield reduction. By mimicking the effect of climate change on maize grain yield, it was found that 1 °C increase in Tmean resulted in 0.83 t ha−1 (5.8%) maize grain yield reduction. Decrease in PAR also decreased maize grain yield significantly and the 1% decrease in PAR decreased maize grain yield by 0.15 tons per ha. Among all the five cultivars in this study, yield reductions of ZD958 and NH101 induced by 1 °C increase in Tmean were the smallest compared to other three cultivars. The quantitative analysis can provide important guidance to predict possible quantitative outcomes of future changes in crop productivity due to climate change and search for effective mitigation strategies such as cultivar selection.

Genetic analysis and genotype x environment interaction for resistance to northern leaf blight disease in tropical maize (Zea mays L.) genotypes

Northern leaf blight (NLB) disease one of the most devastating foliar diseases of maize accounting for more than 50% yield losses annually. Information on inheritance of NLB resistance of maize population adaptable to tropical environments is required. Thus, hybrids generated through 10 x 10 half-diallel of tropical maize inbred lines were evaluated in five environments to determine their combining ability, impact of NLB disease on grain yield, and genotype x environment (G x E). The 45 single cross F1 hybrids and nine hybrid checks were evaluated across five environments using 9 x 6 alpha lattice with three replications. The greater proportion of general combining ability (GCA) over specific combining ability (SCA) effects across environments implies that additive gene action influences the inheritance of these traits. Predominance of additive gene indicates that rapid progress would be achieved from selection for NLB disease resistance. Regression analysis revealed 1030–1130 kg ha-1 reduction in maize grain yield per increase in NLB severity score. Significant negative relationships (r = -0.33 to -0.77) were reported between grain yield and NLB severity scores in this study. This showed the potential of NLB to cause yield reduction in susceptible genotypes. GGE revealed that the test environments fell into two sectors, indicating the existence of two mega-environments and presence of significant crossover interaction.

DROUGHT TOLERANCE IN INTERVARIETAL MAIZE HYBRIDS

ABSTRACT In the period of planting of second-season maize, there is high climatic instability with greater probability of occurrence of water deficit. This is one of the factors that most cause reduction in maize grain yield. In this context, the aim was to identify stable, irrigation-responsive and drought-tolerant maize genotypes. The experiments were conducted in Mococa / SP and Tatuí / SP, at Instituto Agronômico, in two assays, one under full irrigation conditions and the other under water stress. The experimental design was randomized blocks with 3 replicates. Male flowering, female flowering, plant height, ear height, hectoliter weight, one hundred grain weight and grain yield were evaluated. Joint analysis of variance and stability analysis were performed by the GGEBiplot method. Significant genotype and site effects were observed for all traits. Significant effects of genotype x site interaction were found for all traits except ear height and male flowering. The characteristics most affected by water deficit were male flowering, plant and ear heights and grain yield. Genotypes F2 BM709 x PopTol 2, IAC 46 x PopTol 2, F2 30K75 x PopTol 3 and F2 BM709 x PopTol 3 are considered ideotypes because of their high grain yield, phenotypic plasticity and drought tolerance.

Soil Temperature and Maize Nitrogen Uptake Improvement Under Partial Root-Zone Drying Irrigation

Soil temperature is a major effective factor on the soil and plant biological properties. Irrigation can affect soil temperature and thereby induces a temperature effect on plant growth, which may result in an economic increase due to higher yield and plant nutrition. A field experiment was carried out to investigate the effects of three irrigation strategies including full irrigation (FI), partial root-zone drying (PRD) and deficit irrigation (DI) on soil temperature and the consequent results on the grain yield and N uptake of maize (Zea May L.). Soil temperature was measured by time domain reflectometry (TDR) sensors during the 2010 growing season. Irrigation treatments were applied from 55 to 107 d after planting. The PRD treatment caused soil temperature to be in a favorable domain for a longer period (for over 60% of the measuring dates) as a consequent result of water movement to deeper soil layers compared with the other treatments; the PRD treatment also reduced soil temperature at deeper soil depths to below the maximum favorable soil temperature for maize root growth, which resulted in deeper root penetration due to both water availability and favorable soil temperature. Compared to the FI treatment, the PRD treatment increased root water uptake by 50% and caused no significant reduction in total N uptake, while this was not observed in the DI treatment partially due to the negative temperature effect of DI on plant growth, which consequently affected the water and nutrient uptake. A longer vegetation period in the PRD treatment was observed due to higher leaf N concentrations and no significant reduction in maize grain yield occurred in the PRD treatment, compared with those in the FI treatment. Based on the results, having 15.2% water saving during the whole growing season, the PRD irrigation would positively affect soil temperature and the water and nutrient uptake as a consequent, which thereby would prevent significant reduction in maize grain yield.

A field-modeling study for assessing temporal variations of soil-water-crop interactions under water-saving irrigation strategies

Simulation models are useful tools that may help to improve our understanding of soil-water-plant interactions under innovative water-saving irrigation strategies. In this study, the HYDRUS-2D model was applied to evaluate the influence of deficit irrigation (DI) and partial root-zone drying (PRD) on maize water extractions during two cropping cycles of 2010 and 2011. The model was calibrated and validated using measured soil water content data (expressed as equivalent water depths). Reliable estimates of soil water content were provided by HYDRUS-2D, with root mean square error and mean bias error values of 2.3–5.11 and 1.63–4.93mm, respectively. Root water uptake and maize grain yields were reduced by 13.2–28.8% and 13.6–52.8%, respectively, under different water-saving irrigation treatments compared to full irrigation. However, different root and water repartitions in the PRD treatment with a 25% reduction in the irrigation depth (PRD75) improved soil water utilization and consequently, crop growth. Increased root water uptake (2.2–4.4 times higher than in other treatments) from the 60–100cm soil depth in the PRD75 treatment maintained a favorable daily evapotranspiration rate, resulting in no significant reduction in maize grain yield compared to full irrigation. Consequently, a 15.7–85% increase in water use efficiency for maize cultivation under PRD75 ensured 25% water savings without threatening food security in the study area. It can be concluded that HYDRUS-2D can be successfully used to optimize water management under local water-stress conditions.

Improved soil–plant water dynamics and economic water use efficiency in a maize field under locally water stress

ABSTRACTSoil–plant water dynamics is a major driving factor on crop yield which could be improved under optimal irrigation strategy. The soil water dynamics under partial root-zone drying (PRD) and its consequent effects on maize economics returns were investigated in a two-year field study in the research field of Sari Agricultural Sciences and Natural Resources University. Irrigation treatments included full irrigation (FI) and two PRD treatments including PRD1 and PRD2, receiving 100%, 75% and 55% of crop water demand at each irrigation event, respectively. TDRs were used for measuring soil water contents on a daily basis. Economic analysis was done based on net present value (NPV), benefit-to-cost ratio (B/C) and internal rate of return (INRR) indices. Applying PRD1 treatment increased soil wetting front advance by 110–330% compared those for other treatments which caused 50% increase in root water uptake. Improved soil water dynamics under PRD1 prevented a significant reduction in maize grain yield, leading to 37.7%, 6.14% and 192% increase in NPV, B/C and INRR, respectively, under PRD1 than those for FI treatment. Thus, PRD1 was the most economic water-saving irrigation strategy under which 25% of irrigation water would be saved due to a better utilization of soil water supply.

Transformation, evaluation of GTGene and multivariate genetic analysis for morpho-physiological and yield attributing traits in Zea mays

Maize is the 3rd major crop grown all over the world that fulfills the needs of millions of people. Various biotic and abiotic factors caused reduction in grain yield of maize, among them weeds show most adverse effects. Objective of this study was to develop glyphosate resistance maize for developing maize hybrids and synthetic varieties with high grain and fodder yield potential. Glyphosate is a broad spectrum herbicide and resistance of crop against the herbicide, allows post emergence application, which otherwise is impossible. Higher GTG crude protein (479.94?g/g) was recorded for CIL 194-975 plant. The plant CIL 194-1786 showed higher expression level of GTG protein, indicated that transformation efficiency was better for line CIL-194 than CIL-123. GTGene stably integrated to the genome of the maize lines CIL-194 and CIL-123, these transformed lines showed more ability to cope with herbicides as compared with non-transformed lines in greenhouse and field trials. The transgenic lines were sown in field and data was recorded for various morpho-physiological, grain, fodder yield and quality traits. Data was statistically analyzed to check significance of results at <0.05% probability level. It was concluded from heritability, genetic advance, stepwise multiple linear regression, principle component and factor analysis that the selection on the basis of grain yield, green fodder yield, stem diameter, cob weight, stomata conductance, chlorophyll contents, photosynthetic rate, cob length, grain protein, grain oil, embryo percentage and grain starch may be fruitful keeping in view as the major contributing traits to improve crop yield and production. It was suggested that the transgenic lines for glyphosate resistance may be used to develop transgenic hybrids and synthetic varieties with higher grain yield with high quality.

Yield of maize (Zea mays L.) logistically declined with increasing length of the consecutive visible wilting days during flowering

Under future climate conditions, the frequency and severity of drought are expected to increase. Maize (Zea mays L.) is susceptible to drought, especially at flowering. The objective of this study was to investigate the effect of consecutive days of visible wilting (DAW) during tassel emergence using two types of Korean maize hybrids, Gwangpyeongok (Gwp; normal) and Ilmichal (Ilmi; waxy). Traits related to plant growth and yield were measured at harvest. Drought stress during tassel emergence significantly reduced the number of green leaves per plant. Silking was delayed due to drought stress during the stage of tassel emergence, although anthesis was only slightly affected, which resulted in an increase in the anthesis-silking interval (ASI). For each DAW, ASI increased by 1.6 days and 0.8 days for Gwp and Ilmi, respectively. The number of green leaves and ASI showed strong correlation with DAW length and grain yield, which suggested that those factors may be selective traits for drought tolerance at flowering. The filled grain number per plant declined logistically with increasing DAW due to reductions in kernels per row and percentage of filled grains. The filled grain number per plant significantly declined starting at 5 and 10 DAW in Gwp and Ilmi, respectively, which indicated that drought stress effects are dependent on drought severity and the genetic characteristics of specific hybrids. Probit analysis revealed that DAW causing 50% reduction in maize grain yield was about 4.7 and 6.3 days in Gwp and Ilmi, respectively, which resulted in about 13.6% and 9.2% reduction in grain yield per day of DAW, respectively. These results indicate that Gwangpyeongok is more sensitive to drought stress during flowering than Ilmichal.

Maize Growth and Yield under Daytime and Nighttime Solid‐Set Sprinkler Irrigation

Nighttime sprinkler irrigation usually results in lower wind drift and evaporation losses (WDELs) and better irrigation uniformity compared with daytime irrigation. However, daytime sprinkler irrigation modifies the microclimatic conditions within the crop canopy which could result in improved crop growth. We studied the effect of daytime and nighttime irrigation on the growth and yield of maize (Zea mays L.) irrigated with a solid‐set sprinkler system. Two irrigation treatments were tested: daytime irrigation (starting at 1000 Greenwich Mean Time, GMT) and nighttime irrigation (starting at 2200 GMT). The same irrigation amount was applied in both treatments. The irrigation amount was determined as the difference between the crop evapotranspiration (ETc) and the effective precipitation. The WDELs of daytime irrigation were twice the nighttime irrigation WDELs. Daytime irrigation decreased the mean Christiansen coefficient of uniformity (CU) by 5 to 7% and the seasonal CU by 4%. Daytime irrigation caused a 10% reduction in maize grain yield, mostly due to a reduction in biomass production. The lower soil matric potential found with daytime irrigation late in the season indicated that a progressive water stress occurred that was due to less water availability and was caused by the higher WDEL for daytime irrigation. Even though positive microclimatic changes have been reported with daytime sprinkler irrigation, the results of our study indicate that they cannot compensate the negative effects caused for the crop by less water reaching the soil root zone because of increased WDEL and by poorer irrigation uniformity.

Effects of Soil Degradation on Crop Productivity in East Africa

ABSTRACT A rapid increase in population is causing severe strain on natural resources and environment of East Africa. Per capita arable land area is declined in several densely populated regions of East Africa. Two major issues in soil and environmental degradation, i.e., greenhouse effect and water quality are described. Three principal soil degradation processes with reference to productivity are physical, chemical and biological degradation. Soil physical degradation can affect crop growth and yield by decreasing root depth and available water and nutrient reserves and soil erosion can lead to yield loss by affecting soil organic carbon, nitrogen, phosphorus, and potassium contents and soil pH. Reduction in maize grain yield on moderately and severely eroded soils compared with uneroded soils in Tanzania was 14 to 39%. Chemical degradation is caused by the processes of nutrient depletion and/or loss of organic matter, acidification and toxic aluminum, salinization, and industrial and mining activities. In Tanzania, a modest cropping system of maize and bean removed about 58,13, and 56 kg ha−1 of N, P, and K, respectively. The average use of fertilizers in this cropping system was only 22.5 kg ha−1 and thus resulting in “nutrient mining.” Principal issues of agricultural sustainability are discussed.