ChileanJAR

Three corn hybrids, lNlA-8 (early maturing), P-3369A (semi-late), and G-4776 (late), were sown at the Quilamapu Experiment Station (lNlA), Chillán, Chile, on October 1980, to study dry matter accumulation (DMA). A split plot cfesign, with 4 replications, the main plots being the corn hybrids and the subplots the 10 harvesting dates, was used. The production parameters were adjusted by covariance to the average population of each hybrid, that varied according to their earlines. With these values a response curve was fitted Un Y = a + b lnX - cX, were Y is the production parameter and X days from sowing to harvesting). For the three hybrids, DMA continued beyond the milky stage. Participation of the ears in the total plant weight increased with plant maturity, reaching aboye 60% at the maximum DMA. The whole plant crude protein content tended to be constant beyond the milky stage. Optimum harvesting times, to obtain maximum silage production, with an adequate humidity level, were: for the early maturing hybrid, from early to mid March;for P-3369A, from late March to early April; and for the late hybrid, from early to late April.