Browsing by Author "Bester, Cecilia"

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    Genetiese polimorfisme in die Suid-Afrikaanse kiemplasmaversameling van verboude patats, Ipomoea batatas (L.) Lam.
    (Stellenbosch : Stellenbosch University, 1991) Bester, Cecilia; Louw, J. H.; Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics and Institute of Plant Biotechnology.
    ENGLISH ABSTRACT: This thesis consists of two articles for publication. The first is a review of sweet potato as agricultural crop and a review of breeding in South Africa before 1950, between 1950 and 1980, and after 1980. This includes a description of the polycross and mass selection methods introduced after 1980, and a critical review of published heritabilities and genetic correlations. The second article deals with the results of analyses of observations in trials undertaken to investigate genetic polymorphism in tuber characteristics, predicted selection response and genotype-environment interaction.
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    Molecular characterisation of apple accessions with respect to aminocyclopropane-1-carboxylic acid synthase gene (ACS1) polymorphism
    (Czech Academy of Agricultural Sciences, 2020-02-07) Mhelembe, Khethani; Kriel, Johan; Bester, Cecilia; Louw, Esme; Roodt-Wilding, Rouvay; Tobutt, Kenneth
    The ARC apple gene bank collection was genotyped for the fruit expressed gene ACS1, in which a short-interspersed element (SINE) in the promoter is known, when homozygous, to correlate with the delayed ethylene production. Primers were designed amplifying products less than 500 bp and 224 cultivars of domestic apple were analysed, 169 not previously genotyped. Of these, 82 were aa (homozygous for the high ethylene allele at 202 bp), 73 were ab and 14 bb (homozygous for the low ethylene allele, with the SINE, at 339 bp). The difference between the allele sizes, 137 bp, observed in the current study is consistent with the indel of 138 bp originally described, but differs considerably from the indel of 166 bp reported in literature. In addition, 21 accessions of other Malus species were analysed. Only one, M. ‘Golden Hornet’, had the b allele, which suggests it may have been introgressed from M. pumila.