MAIZE GRAIN VITREOUSNESS - VARIABILITY WITHIN THE EAR AND EFFECT OF NITROGEN

Maize endosperm vitreousness is an important characteristic of kernels for the dry milling industry because of its influence on the percenta ge of flaking, coarse and regular grits obtained by industrial process ing. Vitreousness, like other kernel characteristics, may depend on ge notype, cultural conditions and kernel position on the ear. The object ives of this research were to study the variability of kernel vitreous ness within the ear and the effect of nitrogen an this characteristic. Field experiments were carried out in 1990 and 1991 al Colmar (Alsace , France), Hybrids DEA and ROSSO were grown in field plots at two nitr ogen levels. Ears were collected al maturity and kernels from five cla sses from the bottom to the tip of the ears were dissected. The dry ma tter weights of all kernel parts decreased from the bottom to the tip of the ear. The highest proportions of horny endosperm were found on t he extremities of the ear. Nitrogen influence on vitreousness was posi tive in 1990 and associated to an increase of the kernel weight. In 19 91 nitrogen gave the heaviest but also the most floury kernels in DEA, and negatively influenced vitreousness without modifying kernel weigh t in ROSSO. In our research the variation in kernel vitreousness was m ore important among years than between kernel positions in the ear or between nitrogen treatments, which had only a minor effect.