[Physical and chemical properties and correlations of early hybrid corn for high valleys]

The evaluation of physical and chemical properties of corn kernels permits the obtaining a wider vision of the experimental hybrids that present good yield and suitable agronomic characteristics. The objectives of this paper were: to classify 24 modern hybrids of early corn according to endosperm texture and to determine their physical and chemical properties and their relationships. The physical parameters tested were: test weight (TW), endosperm texture (TE), pearling index (IP), 1000 kernel wt (W 1000), infrared reflectance (NIR) and color (Ref). The chemical parameters tested were: protein content (Prt), lysine content (Lis) and tryptophan content (Trp). When the hybrids were classified according to IP it was possible to detect 5 hybrids with soft, 12 intermediates and 7 with hard endosperm. The hybrids with hard endosperm presented an average TW of 80.3 Kg/hl, 10.70% of Prt, 0.082% of Trp and 0.35 of NIR, these values were statistically higher than those hybrids with soft endosperm; the IP showed a negative relationship with Prt, NIR and TW; a positive relationship was observed with Ref, meaning that corn grains with soft endosperm presented lower protein content and smaller average flour particle size, larger size grain and whiter color. It was possible to detect hybrids with yields from 8.1 to 9.5 t ha-1 with soft, intermediate and hard endosperms.