Quality of Chopped Maize Can Be Improved by Processing

The aim of this study was to assess the effect of different maize processing technologies, comparing treatments with conventional rollers (control), MCC MAX rollers and a Shredlage crop processor on the quality of chopped maize. All the three types of chopped maize were harvested on the same day from the same field where the same maize hybrid was grown. The chemical composition of chopped maize, degree of grain processing and particle size fractions, and the effect of the treatments on rumen disappearance of dry matter, organic matter, NDF and starch were assessed. The highest degree of grain processing was achieved with the Shredlage processor (79.2%), and at the same time this processing method had a tendency to produce the highest proportion of physically effective fibre (37.2%). Compared to the conventional rollers (control), the chopped maize produced using the Shredlage processor had higher disappearance of dry matter, organic matter and NDF after 48 h of rumen incubation and of starch after 24 h of incubation. The MCC MAX rollers provided higher disappearance of all nutrients compared to the control treatment after both 24 and 48 h of incubation.

Assessment of Functional and Pasting Properties of Fresh Orange Maize Hybrids and Open-Pollinated Varieties as Influenced by Genotype, Harvesting Time, and Growing Location

The study evaluates the effects of genotype, maturity, and growing location on the functional and pasting properties of freshly harvested orange maize hybrids and open-pollinated varieties (OPVs). Eight fresh orange maize hybrid and eight fresh maize OPV, including the control, were harvested at three stages: 20, 27, and 34 days after planting (DAP). The freshly harvested maize samples were lyophilized and characterized for the pasting and functional properties using standard laboratory methods. The peak viscosity, final viscosity, and swelling power of the OPVs increased between 20 and 27 DAP. Additionally, the water absorption capacity increased between 20 and 27 DAP for the maize hybrids, with a decreasing trend between 27 and 34 DAP. However, genotypes 2, from the orange maize hybrid, and 5, amongst the OPV, were outstanding with the highest peak viscosities, indicating good final product quality. The combined ANOVA for the fresh orange maize hybrid and OPV showed a highly significant effect (p ≤ 0.01 and p ≤ 0.001) for the maturity and location on the pasting and functional properties except for the pasting temperature, final viscosity, and pasting time which showed no significant effect. In contrast, the location by genotypes by maturity interactions had no significant effects on the pasting and functional properties of the fresh maize hybrid and the orange OPV except only for the setback, which was highly significant at p ≤ 0.001. Nutritionists, food scientists, and maize breeders could use the information from this study to select the best maize genotypes at the appropriate harvesting period suitable for the production of the preferred maize-based products of consumers.

Maize Hybrids: Mega-Environments in Java Island, Indonesia

Identification of grain yields on stable and high yielding maize hybrids in a wide environment requires high accuracy. There were many stability measurement methods used in multi-environment experiments. However, the relationship between each measurement was still difficult to understand. The objectives of this study were to: 1. identified the effect of growing season, location, hybrids (genotypes), and their interactions (GEIs) on grain yields; 2. determined the relationship between each stability measurement; 3. selected the stable and high yielding maize hybrids in a wide environment; and 4. determined favorable (discriminativeness) locations for testing. The field experiment was conducted at eight locations in Java island, Indonesia during two seasons used a randomized completed block design with three replications. The experimental results showed that the main effects of growing season, location, hybrid, and GEIs, had a significant effect on maize hybrid yields. Stability measurements S(3), S(6), NP(2), NP(3), NP(4), and CVi, belong to the concept of dynamic stability that can be used to selected maize hybrids in favorable environments, while other measurements were classified as in the concept of static stability. Two maize hybrids were successfully selected to have high and stable yields based on numerical and visual measurements, namely SC3 and SC9. The two hybrids can be used as candidates for a sustainable maize development program. GJRS and KARS were the most discriminativeness environments. Both can be used as a favorable environment for selecting the ideal maize hybrid.

SNP-based assessment of genetic purity and diversity in maize hybrid breeding

Assessment of genetic purity of parental inbred lines and their resultant F1 hybrids is an essential quality control check in maize hybrid breeding, variety release and seed production. In this study, genetic purity, parent-offspring relationship and diversity among the inbred lines were assessed using 92 single-nucleotide polymorphism (SNP) markers. A total of 188 maize genotypes, comprising of 26 inbred lines, four doubled haploid (DH) lines and 158 single-cross maize hybrids were investigated in this study using Kompetitive Allele Specific Polymerase Chain Reaction (KASP) genotyping assays. The bi-allelic data was analyzed for genetic purity and diversity parameters using GenAlex software. The SNP markers were highly polymorphic and 90% had polymorphic information content (PIC) values of > 0.3. Pairwise genetic distances among the lines ranged from 0.05 to 0.56, indicating a high level of dissimilarity among the inbred lines. A maximum genetic distance of (0.56) was observed between inbred lines CKDHL0089 and CML443 while the lowest (0.05) was between I-42 and I-40. The majority (67%) of the inbred lines studied were genetically pure with residual heterozygosity of <5%, while only 33% had heterozygosity levels of >5%. Inbred lines, which were not pure, require purification through further inbreeding. Cluster analysis partitioned the lines into three distinct genetic clusters with the potential to contribute new beneficial alleles to the maize breeding program. Out of the 68 hybrids (43%) that passed the parent-offspring test, seven hybrids namely; SCHP29, SCHP95, SCHP94, SCHP134, SCHP44, SCHP114 and SCHP126, were selected as potential candidates for further evaluation and release due to their outstanding yield performance.

Unravelling the Effect of Provitamin A Enrichment on Agronomic Performance of Tropical Maize Hybrids

Maize is consumed in different traditional diets as a source of macro- and micro-nutrients across Africa. Significant investment has thus been made to develop maize with high provitamin A content to complement other interventions for alleviating vitamin A deficiencies. The current breeding focus on increasing β-carotene levels to develop biofortified maize may affect the synthesis of other beneficial carotenoids. The changes in carotenoid profiles, which are commonly affected by environmental factors, may also lead to a trade-off with agronomic performance. The present study was therefore conducted to evaluate provitamin A biofortified maize hybrids across diverse field environments. The results showed that the difference in accumulating provitamin A and other beneficial carotenoids across variable growing environments was mainly regulated by the genetic backgrounds of the hybrids. Many hybrids, accumulating more than 10 µg/g of provitamin A, produced higher grain yields (>3600 kg/ha) than the orange commercial maize hybrid (3051 kg/ha). These hybrids were also competitive, compared to the orange commercial maize hybrid, in accumulating lutein and zeaxanthins. Our study showed that breeding for enhanced provitamin A content had no adverse effect on grain yield in the biofortified hybrids evaluated in the regional trials. Furthermore, the results highlighted the possibility of developing broadly adapted hybrids containing high levels of beneficial carotenoids for commercialization in areas with variable maize growing conditions in Africa.

Characterization of Maize Hybrids (Zea mays L.) for Salt Tolerance at Seedling Stage

Salinity is the most atrocious environmental aspects restricting the productivity of agricultural crops. To fulfill global increasing demand of food, selection of salt tolerant genotypes to get production from salt affected soils is imperative. In the present experiment, ten maize genotypes were evaluated against four salinity levels (control, 40 mM, 80 mM and 120 mM NaCl) using different agronomic and physiological criteria. Significant variations were observed in all morpho-physiological and ionic attributes in all maize hybrids. Results depicts that maize hybrid 2225 exhibited salt tolerance and show higher plant biomass, chlorophyll and water contents, membrane stability along with K+/Na+ ratio. While maize hybrid 8711 had lower plant growth among all maize hybrids and considered as salt sensitive genotype. The results can be used as a selection tool for salinity tolerance in maize and provide a better source for breeders for further assessment on saline lands.

Optimizing Genomic-Enabled Prediction in Small-Scale Maize Hybrid Breeding Programs: A Roadmap Review

The usefulness of genomic prediction (GP) for many animal and plant breeding programs has been highlighted for many studies in the last 20 years. In maize breeding programs, mostly dedicated to delivering more highly adapted and productive hybrids, this approach has been proved successful for both large- and small-scale breeding programs worldwide. Here, we present some of the strategies developed to improve the accuracy of GP in tropical maize, focusing on its use under low budget and small-scale conditions achieved for most of the hybrid breeding programs in developing countries. We highlight the most important outcomes obtained by the University of São Paulo (USP, Brazil) and how they can improve the accuracy of prediction in tropical maize hybrids. Our roadmap starts with the efforts for germplasm characterization, moving on to the practices for mating design, and the selection of the genotypes that are used to compose the training population in field phenotyping trials. Factors including population structure and the importance of non-additive effects (dominance and epistasis) controlling the desired trait are also outlined. Finally, we explain how the source of the molecular markers, environmental, and the modeling of genotype–environment interaction can affect the accuracy of GP. Results of 7 years of research in a public maize hybrid breeding program under tropical conditions are discussed, and with the great advances that have been made, we find that what is yet to come is exciting. The use of open-source software for the quality control of molecular markers, implementing GP, and envirotyping pipelines may reduce costs in an efficient computational manner. We conclude that exploring new models/tools using high-throughput phenotyping data along with large-scale envirotyping may bring more resolution and realism when predicting genotype performances. Despite the initial costs, mostly for genotyping, the GP platforms in combination with these other data sources can be a cost-effective approach for predicting the performance of maize hybrids for a large set of growing conditions.