Angeline van Biljon

Genetic diversity assessment in sorghum accessions using qualitative morphological and amplified fragment length polymorphism markers

Qualitative morphological and amplified fragment length polymorphism (AFLP) markers were compared for assessment of genetic diversity. Nine qualitative morphological traits were recorded to compare genetic relationships among 17 sorghum accessions with information derived from six AFLP primer combinations analysis. The mean morphological genetic similarity was lower in comparison to similarity computed using AFLP markers. Genetic similarity measured by AFLP markers was similar within the Ethiopian and South African material, as well as between South African and Ethiopian material. Morphological similarity was much higher in the Ethiopian material than in the South African material, indicating that the genotypes were related. The two techniques described genetic variability in different ways. Dendrogram generated from the morphological data matrix separated accession 216737 as being genetically distinct from the rest of the accessions. Accessions M101 and 97MW6127 were the most dissimilar accessions based on AFLP data.

Microsatellite-based assessment of five Solanum nigrum complex species and their progeny

Abstract The aim of this study was to investigate the potential of simple sequence repeats as genetic markers in five species of the Solanum nigrum complex found in South Africa as well as their progeny. Some of the primers developed for sorghum, tomato, pepper and potato were used. Twenty-nine random sets of primers were selected for screening and seven were used to amplify each of the parents and their progeny. The optimum conditions were not the same for the various primer pairs with annealing temperatures of 45, 50 and 55 °C for different primers. The genetic-distance value amongst the species and their progeny varied from 0.33 to 0.55, showing the close relationship between entries and confirming the fact that the Solanum nigrum complex is a group of plants very closely related, yet the parents and their progeny could be clearly distinguished. This marker system therefore was very effective in distinguishing closely related accessions arising from a similar pedigree and could be used for molecular breeding in this species.

The role of proline and root traits on selection for drought-stress tolerance in soybeans: a review

Drought stress is a major limiting factor in soybean production. It reduces both the yield and its components. This is dependent on the level and occurrence of drought stress with respect to the growth stages of the plants. Breeding for drought stress tolerance can sustainably reduce the impact of drought stress. However, occurrence of drought stress is irregular over locations and seasons, making selection for drought tolerance challenging. Effort is being put into using proline accumulation as a measure to monitor stress tolerance of higher plants. It is evident that proline accumulates with increased drought stress. Genotypic differences exist in proline accumulation among soybean cultivars of different sensitivities to drought stress. There is a positive correlation between stress-induced proline accumulation and drought tolerance. The capacity of root traits to explore spatial domains with limited water and their ability to dynamically respond to soil-water deficit are also being investigated as indicators for drought stress tolerance. Root traits response to available soil water is a heritable trait and genotypic variation is evident in soybeans. This paper reviews the effects of drought stress and advances in the use of proline accumulation and root traits as selection tools for drought tolerance in soybean.

Genetic variability among sorghum accessions for seed starch and stalk total sugar content

Sorghum (Sorghum bicolor (L.) Moench) is a staple food grain in many semi-arid and tropical areas of the world, notably in sub-Saharan Africa because of its adaptation to harsh environments. Among important biochemical components for sorghum for processors are the levels of starch (amylose and amylopectin) and total sugar contents. The aim of this study was to determine the genetic variation for total starch in the seed, its components and total sugar in the stalks of the sorghum accessions from Ethiopia and South Africa. Samples of 22 sorghum accessions were evaluated. Significant variations were observed in total starch (31.01 to 64.88 %), amylose (14.05 to 18.91 %), the amylose/amylopectin ratio (0.31 to 0.73) and total stalk sugar content (9.36 to 16.84 %). Multivariate analysis showed a wide genetic variation within and among germplasm accessions which could be used in the selection of parental lines for the improvement of traits of interest through breeding. The variation found among the sorghum accessions shows that an improved total starch and starch components and stalk sugar contents can be achieved through crossing these selected genotypes.

Overall liking and sensory profiling of boiled Amaranthus leaves using the Check-all-that-apply question

ABSTRACT The study investigated consumers’ overall liking and sensory profiling of 13 boiled Amaranthus genotypes by using the Check-all-that-apply question. Fifty consumers ranked their preference on a nine-point hedonic scale to determine overall liking of boiled samples. Additionally, 100 consumers completed a CATA question, which contained 19 descriptive terms related to Amaranthus leaves. Significant differences were found in the frequency in which consumers used 11 out of the 19 terms. Correspondence analysis, explaining 68.1% variance, illustrated differences in sensory characteristics between genotypes. Hierarchical cluster analysis identified three consumer segments, indicating the heterogeneous acceptance of samples. External mapping of the samples’ configuration identified regions of maximum liking. Sensory characteristics of Amaranthus leaves varied between genotypes and species, with no relationship between specific species and their sensory properties. The information obtained can be recommended to farmers to be incorporated into breeding programmes.

Recent advances in banana (musa spp.) biofortification to alleviate vitamin A deficiency

Abstract Vitamin A deficiency (VAD) is one of the most prevalent micronutrient deficiencies that disproportionately affects low income populations in developing countries. Traditional breeding and modern biotechnology have significant potential to enhance micronutrient bioavailability in crops through biofortification. Bananas (Musa spp.) are economically important fruit crops grown throughout tropical and sub-tropical regions of the world where VAD is most prevalent. Some banana genotypes are rich in provitamin A carotenoids (pVACs), providing an opportunity to use bananas as a readily available vehicle for provitamin A delivery. This review summarizes the progress made in carotenoid research in bananas relative to banana diversity and the use of conventional breeding and transgenic approaches aimed at banana biofortification to address vitamin A deficiency. Existing reports on sampling strategies, pVAC retention and bioavailability are also evaluated as essential components for a successful banana biofortification effort. The wide variability of pVACs reported in banana cultivars coupled with recent advances in unraveling the diversity and genetic improvement of this globally important but often-neglected staple fruit crop underscores their importance in biofortification schemes.

The Content of Tocols in South African Wheat; Impact on Nutritional Benefits

Wheat is a major component within human consumption, and due to the large intake of wheat, it has an impact on human nutritional health. This study aimed at an increased understanding of how the content and composition of tocols may be governed for increased nutritional benefit of wheat consumption. Therefore, ten South African wheat cultivars from three locations were fractionated into white and whole flour, the content and concentration of tocols were evaluated by high performance liquid chromatography (HPLC), and vitamin E activity was determined. The content and composition of tocols and vitamin E activity differed with fractionation, genotype, environment, and their interaction. The highest tocol content (59.8 mg kg−1) was obtained in whole flour for the cultivar Elands grown in Ladybrand, while whole Caledon flour from Clarence resulted in the highest vitamin E activity (16.3 mg kg−1). The lowest vitamin E activity (1.9 mg kg−1) was found in the cultivar C1PAN3118 from Ladybrand. High values of tocotrienols were obtained in whole flour of the cultivars Caledon (30.5 mg kg−1 in Clarens), Elands (35.5 mg kg−1 in Ladybrand), and Limpopo (33.7 mg kg−1 in Bultfontein). The highest tocotrienol to tocopherol ratio was found in white flour (2.83) due to higher reduction of tocotrienols than of tocopherols at fractionation. The quantity and composition of tocols can be governed in wheat flour, primarily by the selection of fractionation method at flour production, but also complemented by selection of genetic material and the growing environment.

The development and release of maize fortified with provitamin A carotenoids in developing countries.

ABSTRACT Micronutrient deficiencies have been identified as major public health problems affecting a large part of the worlds population. Biofortification of staple crops like maize has been proposed as one of the most cost effective and feasible approaches to combat micronutrient deficiencies. Studies have shown that provitamin A from biofortified crops is highly bioavailable and has the capacity to improve vitamin A status of vulnerable groups. Most people in sub-Saharan Africa subsist on maize and many people may benefit from consumption of provitamin A carotenoid biofortified maize, especially women and children. With the exception of transgenic golden rice, biofortified crops have received considerable acceptance by most communities. Negative perceptions associated with yellow maize do not affect orange maize, which is, for example, well-liked in rural Zambia. With proper policy frameworks and full commercialization, provitamin A maize can address the problem of vitamin A deficiencies among poor nations with maize-based diets.