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  • Author or Editor: M. T. Labuschagne x
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The bread making quality of Ethiopian cultivars was studied using 18 quality traits at low and high protein environments. Significant variation was observed between genotypes with a broad range of milling, rheological and baking traits. Three different quality prediction models were constructed explaining 48% to 73% of the variation of mixing time and loaf volume, respectively. SDS-sedimentation alone accounted for 56% of the variation in loaf volume at the high protein environment. The variation of mixing time due to protein content alone was 37% at the low protein environment. SDS-sedimentation and mixograph mixing time were common in the three models. SDS-sedimentation, protein content and mixing time can be used as selection criteria in breeding programs where resources are limited. Hectoliter weight and grain weight also contributed to the variation of loaf volume and mixing time.

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The mixograph performs certain rheological measurements during dough mixing and is a good predictor of wheat end-use quality. The aim of this study was to determine the expression and the heritability of mixing characteristics measured with Mixsmart® software and some quality characteristics in hard red spring wheat parents and their F1 progeny. Six parents varying in midline peak time and envelope peak time were crossed in a half diallel design. Parents and progeny were planted in three different environments. General combining ability (GCA) was a significant source of variation for the measured characteristics, and parents differed widely in terms of GCA effects. Midline-development time, -peak integral and -peak time showed high narrow sense heritability. Envelope peak-integral and -tail width displayed high narrow sense heritability for some, but not all locations. High GCA:SCA (specific combining ability) ratios indicated the prevalence of additive gene effects for midline-development time, -peak integral and -peak time, indicating that these characteristics are largely genetically determined, and that selection for them should lead to genetic gain.

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Sorghum is a drought tolerant cereal and staple food which is a dietary source of protein and more than 20 minerals. The concentration of the mineral elements and protein content in sorghum varies due to genotypic and environmental influences and genotype by environment interactions. The objective of this study was to determine the contents of eight mineral elements (Ca, Fe, K, Mn, Na, P, Zn and Mg) and protein in sorghum genotypes. The analysis of variance showed significant differences in mineral and protein contents. There was a significant relationship between Zn and Fe and between protein and P and Zn. The principal component (PC) analysis showed that Fe, Mn, P, Zn and protein contributed largely to clustering of the genotypes in PC1; Ca, P and Mg to PC2 and Ca, K and Na to PC3. The presence of a considerable amount of compositional variability of mineral and protein contents among tested genotypes suggests that they can be a valuable source of genes for nutritional quality improvement of sorghum.

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Sorghum is, globally, the fifth most important cereal after maize, rice, wheat and barley. The crop is tolerant to semi-arid and arid climatic conditions. Twenty-five sorghum varieties grown in South Africa were evaluated in the field at two locations with the objective of identifying high yielding, micronutrient dense genotypes. Two clusters were formed based on measured traits. Tx430 (G13), CIMMYT entry 49 (G12), E35-1 (G16), Framida (G19), IS1934 (G7) and IS14380 (G14) formed cluster A. The rest of the sorghum entries formed cluster B. Wide variation was exhibited for grain yield, ranging from 1.12 t ha−1 to 3.96 t ha−1 with a mean grain yield of 2.83 tha−1. Analysis of variance also revealed significant differences among the varieties for protein, total starch, amylose and mineral content. Two varieties, Tx430 and AR-3048 exhibited very high protein content. Fe content ranged from 43.7 mg kg−1 (Kuyuma) to 61.2 mg kg−1 (IS14380) with an average of 50.5 mg kg−1. Zn content ranged from 13.7 mg kg−1 (Macia) to 23.4 mg kg−1 (Tx430) with a mean of 17.4 mg kg−1. Grain yield was significantly positively correlated with plant height, panicle weight and thousand kernel weight. Significant positive correlations were observed between Fe content and Zn, Cu, Mn and P. This data indicated that simultaneous genetic improvement of sorghum varieties for Fe and other important minerals, and starch content in the same genetic background was possible, without a penalty to grain yield.

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