Correlated responses to recurrent selection for grain yield in maize

Experiments were conducted in three field environments with the following objectives: (1) to evaluate the progress from seven cycles of reciprocal recurrent selection in Iowa Stiff Stalk Synthetic (BSSS(R)] and Iowa Corn Borer Synthetic #1 (BSCBl(R)] and six cycles of half-sib family selection in \u27Alph\u27 (i.e., BS12) maize (Zea mays L.) populations, (2) to compare the response of unimproved and improved maize variety hybrids to different levels of nitrogen fertilizer and plant density, and (3) to evaluate the influence of nitrogen and plant density on the morphological and physiological traits associated with recurrent selection for grain yield in maize. Each experiment was grown in randomized complete blocks with a split-split-plot arrangement and two replications. Nitrogen fertilizer levels (0, 90, 180, and 270 kg N/ha) were main plots, plant densities (39,500; 59,300; 79,000; and 98,800 plants/ha) were subplots, and five variety hybrids, BSSS(R)CO x BSCBl(R)CO, BSSS(R)C5 x BSCB1(R)C5, BSSS(R)C7 x BSCB1(R)C7, BS12CO x B14A, and BS12C6 x B14A, were randomized as sub-subplots. We obtained data on grain yield and grain-yield components, flowering traits, plant traits, leaf area, leaf orientation, lodging, dry-matter productivity, and harvest index

Agronomic traits associated with genetic gains in maize yield during three breeding eras in West Africa

Studies on genetic gains in grain yield in maize (Zea mays L) is crucial to identify traits of potential value and the necessary modifications in breeding methodologies and strategies for increased progress in future breeding ef-forts. Fifty early-maturing maize cultivars developed during three breeding eras were evaluated for 2 yr in two field experiments involving 16 multiple stress (drought, Striga-infested, and low soil nitrogen) environments and 35 optimum environments to determine the changes in agronomic traits associated with the genetic gains in grain yield over three breeding eras. The average rate of increase in grain yield was 30 kg ha–1 yr-1 corresponding to 1.59% annual genetic gain across multiple stresses. Among the agronomic traits under stress, only ears per plant (0.32% year-1), ear aspect (-0.51% year-1), plant aspect (-0.24% year-1) and days to anthesis (0.11% year-1) changed significantly (P<0.05 or <0.01) during the three eras. The increase in grain yield from the first to the third generation cultivars across stress environments was associated with significant improvements in plant and ear aspects, increased ears per plant and stay green characteristic. Under optimal growing environments, the increase in grain yield from the first to the third generation cultivars was 1.24% per annum and the gain was associated with significant improvements in plant and ear heights, plant and ear aspects, husk cover, and increased ears per plant. The results indicated that substantial progress has been made in breeding for cultivars with combined tolerance/resistance to the three stresses during the past 22 years

Genetic variability and trait association under thrips (Megalurothrips sjostedti Trybom) infestation in cowpea (Vigna unguiculata [L.] Walp.)

Open Access Article; Published online: 14 May 2021Flower bud thrips is one of the most destructive insect pests of cowpea in sub-Saharan Africa. Information on genetic variability among cowpea germplasm and interrelationships among traits under thrips infestation would facilitate the development of resistant varieties. The objectives of the study were to assess genetic variability for thrips resistance, estimate heritability of yield and other traits and investigate inter-trait relationships under thrips infestation. One hundred and fifty-six cowpea lines, including one resistant and one susceptible check, were screened for resistance under natural infestation at two locations in Nigeria, in 2016. Test lines were scored for thrips damage weekly for three consecutive weeks, after removal of spreader plants, to obtain damage scores (DS) 1, 2 and 3 while data were collected on agronomic traits. The data were subjected to analysis of variance from which genetic components of the phenotypic variance were computed. Interrelationships among traits were determined using phenotypic and genotypic correlation, and sequential path analyses. Significant variability was observed among test lines. Lines TVu 6824 and TVNu 1307 were identified as possessing thrips resistance. DS3 had significant genetic and phenotypic correlations with DS1, DS2 and yield-related traits. Number of pods per peduncle, number of peduncles per plant and DS3 were identified as first-order traits. Heritability estimates ranged from 0.55 to 0.73. Genetic variability among the lines suggests the possibility of genetic control of thrips while number of pods per peduncle, number of peduncles per plant and DS3 would serve as useful selection criteria for thrips resistance

Performance characteristics and egg quality of Commercial Layers Fed Processed Mango Seed Kernel meal at varying inclusion levels

The effect of dietary inclusion of mango seed kernel meal (MSKM) was investigated in commercial layers using 390 twelve weeks growing pullets. The mango seed kernel was cut opened sliced and divided into four equal parts. First part was soaked in cold water for 24 hours then drained and sundried. Second part was soaked in lye for 24 hours drained and sundried while the third part was parboiled for 20 minutes then sundried and the last part was sundried only. These were then used to formulate twelve experimental diets and one control diet. Birds were fed for a period of 8 and 12 weeks during growing and laying phase respectively. Growth performance, egg production and quality parameter were monitored. A significant (P&lt;0.05) difference was recorded in the final weight, weekly weight gain and feed conversion ratio with 15% parboiled having the overall best performance. Egg production performance took a different dimension, birds placed on 10% lye treated MSKM based diet had the best results in feed intake per 30 eggs and cost of feed per tray of egg. Laying birds placed on 20% sundried MSKM based diet was least performed. All parboiled MSKM based diets proved to be better than the control. Haugh unit and yolk index were influenced significantly (P&lt;0.05) by the utilization of differently processed MSKM. Birds fed 15% lye and 15% cold water treated MSKM based diet produced egg with best and least haugh unit respectively

Plant density and nitrogen responses of maize hybrids in diverse agroecologies of west and central Africa

Open Access Journal; Published online: 05 Feb 2021Maize (Zea mays L.) production in West and Central Africa is constrained by drought, low soil-N and Striga infestation. Breeders in the region have developed and commercialized extra-early and early-maturing hybrids (E-EH and EH), which combine high yield potentials with tolerance/resistance to the three stresses. Hybrids of both maturity groups are new to the farmers; thus, the urgent need to recommend appropriate agronomic practices for these hybrids. We investigated the responses of four hybrids belonging to extra-early and early-maturity groups to plant density (PD) and nitrogen (N) application in five agroecologies. The EHs consistently out-yielded the E-EHs in all the five agroecologies. The hybrids showed no response to N-fertilizer application above 90 kg ha-1. All interactions involving N had no significant effect on all traits except in few cases. The E-EHs and EHs had similar response to PD; their grain yield decreased as PD increased. Contrarily, flowering was delayed and expression of some other agronomic traits such as plant and ear aspects became poorer with increased PD. Optimal yield was obtained at approximately 90 kg N ha-1 and 66,666 plants ha-1. Most of the measured traits indicated high repeatability estimates (i.e. ≥ 60) across the N levels, PDs and environments. Evidently, the hybrids were intolerant of high PD

Methyl orange, an organic dye: its health impact and sorptive removal from waste water

AbstractMethyl Orange (MO) a member of Azo dyes are commonly used as synthetic dyes in textile, food, paper and cosmetics. Their use is easy and cost-effective, compared with natural dyes. However, azo bonds are hardly removed because of their high water solubility as well as low exhaustion with the potential for persistence and accumulation in the environment, therefore aqueous solution of MO is toxic and irritating. Thus, the removal of them from industrial wastewaters is capital with regard to protect public health, environment, and aquatic life

Genetic analysis of grain yield and resistance of extra-early-maturing maize inbreds to northern corn leaf blight

Open Access Article; Published online: 11 Feb 2021Maize (Zea mays L.) is a food security crop in sub-Saharan Africa (SSA). Incidence of northern corn leaf blight (NCLB), caused by Exserohilum turcicum, in lowlands of SSA during the past decade has caused 30–70% reduction in maize yield. This study (a) examined the combining abilities of extra-early maize (EEM) inbreds and classified them into heterotic groups; (b) elucidated gene action controlling resistance to NCLB; (c) assessed grain yield (GYLD) and yield stability of EEM hybrids underNCLB infection; and (d) identified testers. One hundred and fiftyEEMhybrids, obtained by crossing 15 inbreds each of white- and yellow-endosperm maize using the North Carolina Design II, plus six checks, were evaluated in nine environments, six of which were inoculated with an isolate of E. turcicum and three of which were non-inoculated in 2018 and 2019. The white and yellow inbreds were placed in three heterotic groups using the heterotic grouping based on general combining ability (GCA) of multiple traits and stability of GYLD using the genotype plus genotype × environment (GGE) biplot analysis. The GCA, specific combining ability (SCA) and genotype × environment (G×E) interactions were significant for GYLD, disease severity, and other measured traits. The GCA effects were more important than the SCA effects for GYLD and NCLB severity scores across environments, implying that recurrent selection could facilitate improvement for GYLD and NCLB resistance. Three inbred testers and four single-cross testers were identified for developing high-yielding NCLB-resistant hybrids. Four white and five yellow single-cross hybrids were identified for on-farm testing and possible commercialization

Applying Innovative Technologies and Practices in the Rapid Shift to Remote Learning

Shifting to remote learning during times of a crisis, such as the COVID-19 pandemic, is very different from well-planned online learning. This paper highlights the experience of shifting to remote learning and outlines lessons learned from the experience. The COVID-19 pandemic brought a wholly new educational context, which uncovered problems such as; course delivery & assessment; communication & misinformation; and technology limitations. This highlights a gap in research on rapid mid-term shift to remote learning in times of a crisis. There are plenty of resources for Information Systems education to draw lessons for effective online learning practices. However, there is limited research on remote learning in response to a crisis, such as COVID-19. This paper presents a case study at Bournemouth University, in which a Business Systems Analysis and Design (BSAD) course was moved to remote learning during COVID-19. The results reflect on the importance of learning focus, students focus, and learning resource focus for remote learning. This includes activities to promote effective communication and information resources, student engagement and support, and remote course delivery and assessment. All these activities are essential elements in a rapid shift from blended learning to remote learning during a crisis, such as COVID-19