Abstract:
Grain hardness affects sorghum and maize processing properties
especially for dry milling. A variety of simple grain quality parameters
were assessed on 17 sorghum and 35 white maize hybrid cultivars
grown in six and four locations, respectively, in South Africa. The purpose
was to determine tests that can be used to distinguish hardness in
commercial sorghum and maize. The grains were characterized by test
weight (TW), thousand kernel weight (TKW), decortication with the
tangential abrasive dehulling device (TADD), and kernel size. Maize
was also characterized for susceptibility to breakage, stress cracking,
and near-infrared transmittance (NIT) milling index. Principal component
analysis showed that, in nontannin and tannin sorghums, TADD
hardness and TW were closely correlated (P < 0.001). In maize, TADD
hardness was closely correlated (P < 0.001) with NIT milling index and
TW. Hence, TADD hardness and NIT milling index or TADD hardness
and TW would be suitable for maize hardness evaluation. A combination
of TADD hardness, TW, TKW, and kernel size >3.35 mm can be
used together to select sorghum grain for hardness. It thus appears that
TADD hardness is an excellent method of estimating both sorghum
and maize hardness that can be applied for routine batch analysis and
cultivar evaluation.
