FORAGE AND GRAIN YIELDS OF WHEAT AND TRITICALE AS AFFECTED BY FORAGE MANAGEMENT-PRACTICES

Most research on the effects of grazing cereal grains has been conduct ed on hard red winter wheat (Triticum aestivum L.) and little informat ion exists concerning the influence of forage harvest on the subsequen t grain yield of other cereal crops. The objectives of this study were to evaluate the effects of forage harvest management on subsequent gr ain yields of triticale (x Triticosecale Wittmack) and wheat to determ ine the growth stage for cessation of forage harvest to optimize grain and forage production. The effect of defoliation until Feekes Growth Stage (GS) 5.0, 6.5, or 8.0 on forage production and grain yield compo nents of 'Terral 817' wheat, 'Jenkins' triticale, and 'Morrison' triti cale was investigated for two growing seasons at Baton Rouge, LA. Plot s harvested up to GS 8.0 produced the greatest forage yield both years . There were no significant differences in mean grain yield of the thr ee cultivars between unclipped cheek plots and plots harvested until G S 5.0 either year. A favorable combination of forage and grain yields in 1987-1988 was achieved if the final forage harvest was made at GS 5 .0, but the highest yield combination in 1988-1989 was produced by con tinuing forage harvest until GS 8.0. Clipping significantly reduced lo dging and disease incidence during the 1988-1989 growing season. Defol iation until GS 8.0 resulted in reductions in number of stems m-2, num ber of spikelets per head, and weight per seed by 37, 11, and 18%, res pectively, resulting in a grain yield reduction of 44% compared with t he undefoliated plants. Forage utilization should be terminated by the first node stage to minimize grain yield reductions due to tiller mor tality, shortened heads, and poor kernel fill.