FACTORS AFFECTING THE PORRIDGE-MAKING QUALITY OF SOUTH-AFRICAN SORGHUMS

Research was undertaken to facilitate the breeding and selection of so rghums with both good milling and good porridge-making characteristics . Twenty seven cultivars were grown in the same locality under rainfed and supplementary irrigation conditions. The two measures of milling quality, abrasive hardness index and Brabender hardness (BH) were sign ificantly correlated (P less than or equal to 0.001) in all sample set s; ie all data, rainfed samples and supplementary irrigation samples. The genetic basis of kernel hardness was confirmed as the hardest and softest cultivars were the same under both cultivation conditions. For all three sample sets there was a significant negative correlation (P less than or equal to 0.05) between kernel hardness according to BH a nd pasting peak viscosity (PPV). PPV is of importance as consumers pre fer stiff porridges. The negative correlation between BH and PPV indic ates that to select sorghum cultivars with good milling and good porri dge-making quality, both kernel hardness and PPV need to be assessed. The sorghums produced under supplementary irrigation were softer accor ding to BH, had higher PPV and set-back viscosity, and the starch cont ained a higher proportion of amylose than those produced under rainfed conditions. Thus, cultivation environment as well as genetics has a m ajor effect on sorghum milling and porridge-making quality.