Consumer acceptance of yellow, provitamin A-biofortified maize in KwaZulu-Natal

Objectives: To assess the acceptance of popular maize food products (phutu, thin porridge and samp), prepared with yellow, provitamin A-biofortified maize varieties, in 212 subjects between the ages of three and 55 years, from rural KwaZulu-Natal.Design: A cross-sectional study.Method: Preschool, primary school and secondary school subjects were randomly selected from two primary schools and one secondary school, respectively, while adult subjects constituted a convenience sample. Pre- and primary school children completed a paired preference test. Secondary school and adult subjects completed a five-point facial hedonic and a preference ranking test. Focus group discussions were conducted using adult subjects.Results: Preschool children preferred yellow maize to white maize food products: phutu (81% vs. 19%; p-value < 0.001), thin porridge (75% vs. 25%; p-value < 0.001) and samp (73% vs. 27%; p-value < 0.001). There was no statistically significant difference in preference for white and yellow maize by primary school children. Secondary school and adult subjects preferred white maize to yellow maize. Focus group discussions confirmed the preference for white maize by the adults.Conclusion: The study findings suggest that yellow, provitamin A-biofortified maize has the potential to succeed as a new strategy of dealing with the serious problem of vitamin A deficiency, especially among children of preschool age. However, in older groups, this strategy is unlikely to be successful, unless other strategies are implemented, including intensive nutrition education programmes on the nutritional benefits of the maize, targeting the market price at which yellow maize is sold, increasing its availability in local grocery stores, and improving its sensory properties through breeding.Keywords: yellow maize, provitamin A, vitamin A deficiency, consumer acceptanc

Acceptance of a complementary food prepared with yellow, provitamin A-biofortified maize by black caregivers in rural KwaZulu-Natal

Objectives: The objective was to assess the sensory acceptability and consumer perceptions of soft porridge made with yellow, provitamin A-biofortified maize by black African female infant caregivers from rural KwaZulu-Natal.Design: This was a cross-sectional study.Setting: The study was conducted at Edendale Hospital, located in the uMgungundlovu District, KwaZulu-Natal province. The hospital serves a high proportion of people from rural areas in this district.Subjects: Sixty black African female infant caregivers participated in the study.Outcome measures: The sensory acceptability of soft porridge made from two varieties of provitamin-A biofortified maize and one variety of white maize were evaluated by black African female infant caregivers (n = 60) using a five-point facial hedonic scale. Some of the subjects (n = 21) participated in focus group discussions to assess consumer perceptions.Results: There was no significant difference in the sensory acceptability of the biofortified maize porridge and the white maize porridge, irrespective of caregiver age (p-value > 0.05). The caregivers expressed a willingness to give their infants porridge made with provitamin A-biofortified maize if it was more affordable, readily available and beneficial to health.Conclusion: The biofortified maize soft porridge was found to be as  acceptable as the white maize soft porridge to black African female infant caregivers from rural KwaZulu-Natal. Provitamin A-biofortified maize has the potential to be used as a complementary food item that would contribute to the alleviation of vitamin A deficiency

Development of a single nucleotide polymorphism (SNP) marker for detection of the low phytic acid (lpa1-1) gene used during maize breeding

Breeding for low phytic acid (LPA) in maize is hampered by a tedious and destructive colorimetric assay in mature dry grain. There are no molecular markers available for the single recessive gene of lpa1-1, restricting breeding programmes. The aim of this study is to develop a molecular marker to identify the lpa1-1 gene at the early vegetative plant stage. The parental lines are temperate LPA line (CM 32) and tropical line (P 16). The lpa1-1 allele is due to a single amino acid change from alanine to valine. The nature of the single nucleotide polymorphism (SNP) marker was validated by DNA sequencing of the parental PCR products. Using high resolution melt (HRM) profiles and normalised difference plots, we successfully differentiated the homozygous dominant (wild type), homozygous recessive (LPA) and heterozygous genotypes. The reduced phytate content of the LPA parental line was confirmed. The profiles from low cost crude and high quality DNA extraction were comparable when distinguishing between the parental lines. The cost of HRM analysis was 8% of the cost of PCR amplification and DNA sequencing. The development of the marker will make maize breeding for LPA efficient and fast, and it will enable the earlier release of lpa1-1 varieties.Keywords: High resolution melt (HRM) analysis, low phytic acid, maize, single nucleotide polymorphism (SNP) markerAfrican Journal of Biotechnology Vol. 12(9), pp. 892-90

Influence of biofortification with provitamin A on protein, selected micronutrient composition and grain quality of maize

Provitamin A-biofortified maize is currently being evaluated for use in the alleviation of vitamin A deficiency. Apart from the differences in provitamin A content, the nutritional composition of provitamin A-biofortified maize compared to white maize is hardly known. This study aimed to evaluate the protein and selected micronutrient composition of biofortified maize varieties and the quality of their grains. A total of 32 provitamin A-biofortified maize varieties was analysed for their starch, fat, protein and mineral content. The milling and storage quality of the biofortified maize grains were also assessed. When compared with the white maize variety, the biofortified varieties were higher in starch, fat and protein, but were lower in iron. The biofortified maize varieties were better sources of most of the essential amino acids relative to the white variety, but, similar to the white maize, they were deficient in histidine and lysine. Overall, the quality of the grains of the biofortified maize varieties was superior to that of the white maize grain, although, the biofortified grains were more susceptible to fungal invasion. This study indicates that, in terms of the nutrients assessed, provitamin A-biofortified maize is generally superior to white maize, except for minerals.Keywords: Biofortification, provitamin A, protein, micronutrient composition, maize.African Journal of Biotechnology Vol. 12(34), pp. 5285-529

Northern leaf blight response of elite maize inbred lines adapted to the mid-altitude sub-humid tropics

Productivity of maize (Zea mays L.) is curtailed by a number of stress factors, predominantly by diseases and insect pests. The Northern leaf blight disease of maize caused by Exserohilum turcicum (Pass.) Leonard and Suggs inflict significant yield losses in the humid tropical regions. The objectives of this study were to determine the leaf blight response of 50 elite maize inbred lines developed for the mid-altitude, sub-humid tropics and to select promising parents for resistance breeding. Inbred lines were evaluated in the field using a 5 × 10 alpha lattice design with three replications. Plants were artificially inoculated at the 4–6 leaf stages during 2011 and 2012. Data on disease severity and incidence, AUDPC and yields were recorded. Inbred lines had significant differences for E. turcicum reactions, and were classified into resistant, intermediate or susceptible categories. The mean disease severity ranged from 2.04% for the inbred line 136-a to 3.25% (Kuleni-C1-101-1-1-1). The upper leaf area infection of inbred lines 143-5-I and 136-a was 3.3%, while the line Kuleni-C1-101-1-1-1 displayed 100% infection. Further, 136-a developed the lowest AUDPC score at 238, whereas Kuleni-C1-101-1-1-1 had the maximum at 700. Overall, inbred lines CML202, 144-7-b, 139-5-j, 136-a, 30H83-7-1-1-1-2-1, ILoo’E-1-9-1-1-1-1-1 and 142-1-e, were identified as promising sources of resistance against E. turcicum. The selected elite inbred lines would be recommended for use in general varietal development, disease management and to enhance maize productivity, in the mid-altitude sub-humid tropics

Evaluation of Bambara groundnut varieties for off-season production in Zimbabwe

Early planting of bambara groundnuts (Vigna subterranea L. Verdc) in the southern Africa enables farmers to fetch premium prices before the markets are flooded with produce from the main summer growing period.However, adaptation of the crop outside the main growing season has not been studied in Zimbabwe. Therefore, this study evaluated 20 varieties at four planting dates covering contrasting temperatures and daylength, at Harare Research Station, during 2000/2001. Planting date was the main plot factor replicated three times and cultivar the subplot. Standard agronomic practices were followed and adequate moisture supplied through supplementary irrigation. Both the planting dates and variety main effects were significant (

RESPONSE OF LOCALLY ADAPTED PEARL MILLET POPULATIONS TO S1 PROGENY RECURRENT SELECTION FOR GRAIN YIELD AND RESISTANCE TO RUST

In the semi-arid zones of Uganda, pearl millet ( Pennisetum glaucum (L.) R. Br.) is mainly grown for food and income; but rust (Puccinia substriata var indica (L.) R. Br.) is the main foliar constraint lowering yield. The objective of the study was to genetically improve grain yield and rust resistance of two locally adapted populations (Lam and Omoda), through two cycles of modified phenotypic S1 progeny recurrent selection. Treatments included three cycles of two locally adapted pearl millet populations, evaluated at three locations. Significant net genetic gain for grain yield (72 and 36%) were achieved in Lam and Omoda populations, respectively. This led to grain yield of 1,047 from 611 kg ha-1 in Lam population and 943 from 693 kg ha-1 in Omoda population. Significant improvement in rust resistance was achieved in the two populations, with a net genetic gain of -55 and -71% in Lam and Omoda populations, respectively. Rust severity reduced from 30 to 14% in Lam population and from 57 to 17% in Omoda population. Net positive genetic gains of 68 and 8% were also achieved for 1000-grain weight in Lam and Omoda, respectively. Traits with a net negative genetic gain in both populations were days to 50% flowering, days to 50% anthesis, days to 50% physiological maturity, flower-anthesis interval, plant height and leaf area.Dans la zones semi-arides en Ouganda, le milet perl\ue9 ( Pennisetum glaucum (L.) R. Br.) est principalement cultiv\ue9 comme culture vivri\ue8re et de rente, mais la maladie de rouille (Puccinia substriata var indica (L.) R. Br.) est la contrainte majeure affectant le rendement. L\u2019ojectif de l\u2019\ue9tude \ue9tait l\u2019am\ue9lioration du rendement en grains et la r\ue9sistance \ue0 la maladie de rouille chez deux populations localement adapt\ue9es milet perl\ue9 (Lam and Omoda), ceci \ue0 travers deux cycles de selection reccurente. Les traitements consistaient \ue0 trois cycles de deux populations localement adapt\ue9es de milet perl\ue9, \ue9valu\ue9es dans trois milieu diff\ue9rents. Un gain genetique significatif de 72 et 36% de rendements en grain a \ue9t\ue9 observe respectivement chez les populations de Lam et de Omoda. Ceci a occasionn\ue9 des rendements en grains de 1,047 kg ha-1 au lieu de 611 kg ha-1 chez la population de Lam et 943 kg ha-1 au lieu de 693 kg ha-1 chez la population de Omoda. Une am\ue9lioration significative de la r\ue9sistance \ue0 la maladie de rouille a \ue9t\ue9 obtenue au sein des deux populations, avec des gains g\ue9n\ue9tiques nets de -55 et -71% respectivement chez les populations de Lam et Omoda. La s\ue9v\ue9rit\ue9 de la maladie de rouille a \ue9t\ue9 de 30% \ue0 14% au sein de la population de Lam population et de 57% \ue0 17% au sein de la population de Omoda. Un gain g\ue9n\ue9tique positif net de 68 et 8% ont \ue9t\ue9 \ue9galement obtenu respectivement pour le poid de 1000 grains de Lam et 1000 de Omoda. Les caract\ue8res comme le nombre jours \ue0 50% de floraison, le nombre de jours \ue0 50% anth\ue8se, le nombre de jours \ue0 50% de maturit\ue9 physiologique, l\u2019intervalle de temps entre la floraison et l\u2019anth\ue8se, la hauteur des plants et la surface des feuilles

Genetic diversity and heterotic orientation of South Africa maize inbred lines towards tropical and temperate testers

Open Access Article; Published online: 20 Jul 2021An ecient hybrid breeding program denes and utilizes few heterotic groups. The objectives of this study were to determine genetic diversity and alignment of South Africa maize inbred lines collection towards tropical and temperate testers. Forty-two maize inbred lines were genotyped with 56110 single nucleotide polymorphism (SNP) DNA markers, using the Illumina MaizeSNP50 Bead chip. The 42 lines were crossed to two tropical and two temperate inbred line testers. The testcrosses were evaluated across seven environments, in South Africa, during 2014-2016. Genotypes and specic combining ability (SCA) effects of hybrids were signicantly different (P<0.05) for grain yield. There was a weak correlation between molecular genetic distances and both grain yield mean and specic combining ability effects of hybrids, indicating that productivity of maize inbred lines could not be reliably determined based on molecular genetic distances. The SCA data was capable of classifying these maize inbred lines into three heterotic groups with respect to both tropical and temperate testers. Only a few lines could not be grouped on the basis of SCA data. The study also indicated high level of diversity among the maize inbred lines, which was shown by both the dendogram and molecular genetic distances. The SNP marker data classied the inbred lines into 11 clusters that could be simplied into three major groups of normal maize endosperm and two groups of quality protein maize (QPM) endosperm types. However, the SNP data indicated that maize lines were more aligned towards tropical than temperate inbred testers. This information would be useful for simplifying heterotic classication of the lines with profound implications for breeding progress

Diallel analysis of soybean (Glycine max L.) for biomass yield and root characteristics under low phosphorus soil conditions in western Ethiopia

Open Access Article; Published online: 06 Feb 2023Combining ability studies under low soil P conditions provides useful information on the inheritance of important traits to improve soybean for low P tolerance. The study aimed at determining the combining ability and gene actions of biomass yield and root traits in soybean under low phosphorus conditions. Nine parental genotypes and their 36 half diallel F2/F3 progenies were evaluated at two locations in Ethiopia on soils of low P availability. Highly significant (P<0.01) general combining ability (GCA) were found for all the traits and specific combining ability (SCA) for root dry weight and root fresh weight; while the SCA effects of all the rest of the traits were significant (P<0.05). The higher relative contributions of GCA over SCA revealed the preponderance of additive gene action in the inheritance of biomass yield, root dry weight, biomass dry weight, root volume, and root fresh weight with respective relative GCA:SCA contributions of (60.6, 39.4), (50.4, 49.6), (54.9, 45.1), (51.1, 48.9), and (52.1, 47.9); while the narrow-sense heritability was high (34.3%) only for biomass yield. Hardee-1 displayed significant (P<0.05) and positive GCA effects for most of the studied traits, and several crosses involving this parent showed superior performances. The traits i.e., biomass yield, biomass dry weight, root volume and root fresh weight showed highly (P<0.001) correlation with grain yield. Thus, breeding programs aiming to improve soybean for biomass yield and root traits under low-P condition can use Hardee-1 as a parent

Genetic analysis of mechanisms associated with inheritance of resistance to sheath rot of rice

Understanding genetic mechanisms controlling inheritance of disease resistance traits is essential in breeding investigations targeting development of resistant genotypes. Using North Carolina design II, 32 F1 hybrids were generated by crossing eight susceptible to four resistant parents and submitted for field evaluation. The analysis of general and specific combining ability (GCA and SCA) indicated involvement of additive and non-additive gene action controlling inheritance of horizontal resistance to sheath rot of rice. High GCA/SCA ratio and high heritability estimates revealed additive effects and were more predominant than none additive ones. The level of dominance indicated dominant genes was more important than recessive genes. Estimates of GCA and SCA analysis suggested that crop improvement programmes should be directed towards selection of superior parents or good combiners, emphasizing on GCA. As far as source of resistance is concerned, most promising genotypes were Cyicaro, Yunertian and Yunkeng. The predominance of additive genetic effects together with the relevance of dominant genes suggested possibilities of improving the resistance by introgression of resistance genes through recurrent selection coupled with phenotypic selection