Capacities of local maize seed enterprises in Mexico: Implications for seed systems development

Where maize plays a critical role in food security, governments and donors have invested heavily in support of local, privately owned, often small and medium sized, maize seed enterprises (maize SMEs). Underpinning these investments are strong assumptions about maize SMEs’ capacity to produce and distribute seed to smallholders. This study assesses the capacities of 22 maize SMEs in Mexico that engaged with MasAgro—a large-scale development program initiated in 2011 that has provided maize SMEs with improved genetic material and technical assistance. Data were collected onsite from in-depth interviews with enterprise owners and managers and complemented with other primary and secondary sources. Overall, maize SMEs showed high levels of absorptive capacity for seed production, but limited signs of learning and innovation in terms of business organization and strategic seed marketing. Asset endowments varied widely among the SMEs, but generally they were lowest among the smaller enterprises, and access to business development services beyond MasAgro was practically nonexistent. Results highlighted the critical role of MasAgro in reinvigorating the portfolios of seeds produced by maize SMEs, as well as the challenges ahead for maize SMEs to scale the new technologies in a competitive market that has long been dominated by multinational seed enterprises. Among these challenges were limited investment in seed marketing, weak infrastructure for seed production, and limited experience in business management. Achieving the food security goals through maize SMEs will require making national maize seed industry development a strategic imperative.

Innovative Low-Cost Naturally Ventilated Maize Seed Storage System

A 22-m3 residential room was converted to a seed storage facility by retrofitting a solar collector on the roof. Three different chimney sizes of diameter and height of 200 mm x 3.6 m, 200 mm x 4.8 m, 300 mm x 3.6 m, and 300 mm x 4.8 m were investigated to determine the best size of the chimney to be used for ventilation in a storage facility. The parameters measured were the air velocity in the chimney duct, as well as the air temperature and relative humidity at the inlet, centre, and outlet of the storage facility. The diameter of the chimney had a significant effect (P<0.05) on the ventilation rate achieved in the storage facility. Significant differences were found between the different chimney diameters and heights (P≤0.05). The 300 mm diameter chimneys were able to extract hot air from the roof solar collector; however, the 200 mm diameter failed. The modified naturally-ventilated seed storage room was able to reduce the relative humidity from 69.7% to a safe relative humidity of 37.9%, while at the same time the temperature increased from 23.3℃ to 35℃ in the 300 mm x 4.8 m chimney.

Gene Expression Variation Explains Maize Seed Germination Heterosis

BackgroundHeterosis has been extensively utilization in plant breeding, however, the underlying molecular mechanism remain largely elusive. Maize (Zea mays), which exhibits strong heterosis, is an ideal material for studying heterosis.ResultsIn this study, there is a faster imbibition and development in reciprocal crossing Zhengdan958 hybrids than in their parent lines during seed germination. To investigate the mechanism of heterosis of maize germination, comparative transcriptomic analyses was conducted between reciprocal crossing hybrids and their parental lines. The gene expression patterns showed that 1324 (47.27%) and 1592 (66.44%) of the different expression genes between hybrids and either parental line display parental dominance up or higher levels in Zhengdan958 and Zhengdan958 reciprocal-cross, respectively. Notably, these genes were mainly enriched in metabolic pathways, including carbon metabolism, glycolysis/gluconeogenesis, protein processing in endoplasmic reticulum, etc.ConclusionOur results provide evidence for the higher expression level genes in hybrid involved in metabolic pathways acting as main contributors to maize seed germinating heterosis. These findings provide new insights into the gene expression variation of maize embryo and improve the understanding of maize seed germination heterosis.

Photosynthesis and antioxidant metabolism modulate the low-temperature resistance of seed germination in maize

Spring maize is usually subjected to low-temperature stress during seed germination, which retards seedling growth even if under a suitable temperature. However, the mechanism underlying maize seed germination under low-temperature stress modulating seedling growth after being transferred to normal temperature is still ambiguous. In this study, we used two maize inbred lines with different low-temperature resistance (SM and RM) to investigate the mechanism. The results showed that the SM line had higher lipid peroxidation and lower total antioxidant capacity and germination percentage than the RM line under low-temperature stress, which indicated that the SM line was more vulnerable to low-temperature stress. Further transcriptome analysis revealed that seed germination under low-temperature stress caused down-regulation of photosynthesis related gene ontology (GO) terms in two lines. Moreover, the SM line displayed down-regulation of ribosome and superoxide dismutase (SOD) related genes, whereas genes involved in SOD and vitamin B6 were up-regulated in the RM line. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that photosynthesis and antioxidant metabolism related pathways played important roles in seed germination in response to low-temperature stress, and the photosynthetic system displayed a higher damage degree in the SM line. Both qRT-PCR and physiological characteristics experiments showed similar results with transcriptome data. Taken together, we propose a model for maize seed germination in response to low-temperature stress.

Differential response of commercial hybrid and open pollinated maize seeds to mechanical damage during seed processing

Hybrids and open pollinated varieties (OPVs) are two commercial maize seed types cultivated in Nigeria. Information on their response to mechanical damage during processing is limited. This study is thus aimed at assessing the response of hybrids and OPVs of maize seeds to mechanical damage which would facilitate fabrication of processing facilities suitable for either of the maize types. Six maize varieties: three hybids (‘New Kaduna’, ‘SDM-1’, and ‘JO-195’) and three OPVs (‘Sammaz 15’, ‘Sammaz 27’ and ‘Suwan-1-stry’) were used for the study. The seed samples were subjected to standard germination, seedling vigour analysis, accelerated ageing, conductivity and fast green tests. The result showed that all the hybrid seed varieties had more damaged seeds than their OPVs counterpart. Shoot length and root length were more affected than other parts of the seedling. There were differences in the magnitude of electrolyte leakage as well as in what time each seed type (hybrid or OPVs) passed through the phases with ‘JO-195’ having the highest rate of electrolyte leakage. Hybrid seeds had lower resistance to mechanical damage and poorer storability when compared with the OPVs. In the overall, for all the traits, ‘Sammaz 15’, the best among OPVs was more promising when compared with ‘SDM-1’ which was the best among hybrid varieties. Processing machine equipment and accessories that are suitable for hybrid seeds might be inappropriate for conditioning OPVs.

Gender inclusivity through maize breeding in Africa: A review of the issues and options for future engagement

With the prioritization of social inclusion in agricultural development, donors and research centers have shown growing interest in gender-intentional varietal development and delivery. Breeding maize varieties that respond to gender-based differences in trait preferences now represents a central objective of maize R&D in the CGIAR and elsewhere. Drawing on literature on gender and maize seed adoption, variety preferences, and seed system constraints, we take stock of knowns and unknowns related to gender-responsive and gender-intentional maize breeding. While recent research on farmers’ variety preferences across crops has yielded insights into gender-based differences, we find that evidence of gender-differentiated preferences for maize varieties remains inconclusive. Ultimately, we identify several research priorities to support gender-intentional maize breeding, including a more nuanced understanding of gender relations in maize production and maize seed decision-making, new and more gender-responsive approaches to measuring farmer preferences and seed demand more broadly, and research to address operational challenges in gender-intentional breeding. We close by identifying some institutional constraints to achieving impact through gender-intentional maize breeding.

Coordinated Effect of Ascorbate Biosynthesis and Recycling in Maize Seed Germination and Seedling Establishment under Low Temperature

The impacts of low temperature occasionally encountered at higher latitude regions on maize seed germination present significant threats to yield and cultivation. Exploring the association of antioxidant system with low temperature (LT) germination could support the breeding strategies for better responding to LT disturbance. In this study, we have examined the germination rate and growth potential of a set of elite maize inbred accessions under LT and normal temperature (NT) conditions in the field. These accessions were found to have variable germination rate and growth potential when grown at LT, whereas the difference is not significant under NT. Physiological study revealed lower hydrogen peroxide content in LT tolerant accessions when compared with sensitive ones. LT-tolerant and LT-sensitive lines maintained similar content of ascorbate (AsA) and glutathione (GSH), whereas the reduced substrate content of which were significantly higher in LT-tolerant accessions. Consistently, activities of ascorbate peroxidase and dehydroascorbate reductase, the enzyme components that responsible for the AsA-GSH recycling, were much higher in LT-tolerant lines. Transcription profile revealed the increased expression of ZmVTC2 gene in LT-tolerant inbred line, which was rate limited step in AsA biosynthesis. These data indicates that the coordinated improvement of AsA biosynthesis and AsA-GSH recycling increase the pool size of the total antioxidants, which ameliorate LT-induced oxidative stress during maize seed germination.

Spermidine Suppressed the Inhibitory Effects of Polyamines Inhibitors Combination in Maize (Zea mays L.) Seedlings under Chilling Stress

Chilling stress greatly inhibited the seed germination, plant growth, development and productivity in this study. The current research aimed to study the effects of different polyamine (PA) inhibitor combinations (Co), e.g., D-arginine (D-Arg), difluoromethylormithine (DFMO), aminoguanidine (Ag) and methylglyoxyl–bis-(guanyhydrazone) (MGBG) at different doses, i.e., 10 µM Co, 100 µM Co, 500 µM Co, 1000 µM Co and 1000 µM Co + 1 mM Spd (Spermidine) in two inbred lines of maize (Zea mays L.), i.e., Mo17 and Huang C, a sensitive and tolerant chilling stress, respectively. The combination treatments of PA inhibitors reduced the biosynthesis of putrescine (Put) in the tissues of both studied inbred lines. Application with 500 µM Co and 1000 µM Co did not result in a significant difference in Put concentrations, except in the coleoptile of Mo17. However, combining Spd to 1000 μM of PA inhibitors enhanced the Put, Spd, spermine (Spm) and total PAs in the roots, coleoptile and mesocotyls. Put and total PAs were increased by 39.7% and 30.54%, respectively, when Spd + 1000 µM Co were applied relative to their controls. Chilling stress and PA inhibitors treatments affected both inbred lines and resulted in differences in the PA contents. Results showed that enzymes involved in the biosynthesis of PAs (ornithine decarboxylase as ODC and S-adenosylmethionine decarboxylase as SAMDC) were significantly downregulated by 1000 µM Co in the tissues of both inbred lines. In contrast, the activity of PAO, a Pas degradation enzyme, was significantly improved by 1000 µM Co under chilling stress. However, Spd + 1000 µM Co significantly improved the activities of ODC and SAMDC and their transcript levels (ODC and SAMDC2). While it significantly downregulated the PAO activity and their relative genes (PAO1, PAO2 and PAO3) under chilling stress. Overall, this study elucidates the specific roles of Spd on the pathway of PA inhibitors and PA biosynthesis metabolism in maize seed development in response to chilling stress. Moreover, the Huang C inbred line was more tolerant than Mo17, which was reflected by higher activities of PA biosynthesis-related enzymes and lower activities of PAs’ degradative-related enzymes in Huang C.

An assessment of physical properties and water holding capacity of soil under different fertilizer applications

This study was carried out at the Teaching and Research Farm of the Department of Agricultural and Bio-Environmental Engineering, School of Engineering, The Federal Polytechnic, Ado-Ekiti to evaluate the water holding capacities of soil under different fertilizers. The experiment was laid out in randomized complete block design (RCBD). The treatments: control, poultry waste, biochar and urea fertilizer replicated four times were incorporated into the soil and maize seed planted. Data collected were subjected to statistical analysis. Soil samples were analyzed for moisture contents, bulk densities, particle densities and water holding capacities. Maize yield was also analyzed. The result obtained showed a significant (p< 0.05) changes in maize yield for the different fertilizers. It also shows a non-significant (p<0.05) effect on water holding capacities of the soils incorporated with different fertilizers. The study concluded that fertilizers has no effect on the water holding capacity of the soil and that poultry waste amended soil will produce higher yield.

Removal of Turbidity and TDS from Wastewater by Using Natural Coagulants — A Review

The highest quantity of wastewater is produced from lather industries that is mixed with oil and other pollutants and under goes to the drains from sinks, toilets, laundries, showers, etc. The wastewater is usually classified as industrial wastewater or municipal wastewater. As the population of the earth is very huge, there is a requirement that the treatment of wastewater become necessary by using different techniques. The removal of TDS and Turbidity are here done by natural coagulants such as Strychnospotatorum, Passion fruit, Phaseolus Vulgaris, Chitosan, Cicer Arietinum, Cactus, Nirmali seeds, Vingna Mungo, Ripe Okra, Surjana seed powder (SSP), Orange peel, Moringa Oleifera, and Maize seed powder. This is found from the literature review that; Jar tests were prominently used in the coagulation-flocculation process for the removal TDS and Turbidity from wastewater. The objective of this review is to find out the scope of different natural coagulants as an alternative compared to other commercial chemical-based coagulants. It has been found from the literature review that these natural coagulants are alternative, cheaper, eco-friendly, and easy to use in wastewater treatment.