ارزیابی هیبریدهای تجاری ذرت علوفه‌ای در تاریخ‌های مختلف کاشت

In order to study the effect of planting date on forage yield and some other characteristics of 13 exotic maize hybrids from Germany, Italy and Croatia and a new hybrid KSC705 produced in Seed and Plant Improvement Institute with a commercial hybrid KSC704 as control, an experiment was conducted at the experimental field of Seed and Plant Improvement Institute in Karaj, in 2011. The experiment was carried out using split-plot in a randomized complete block design (RCBD) with three replications. The main plots consisted of three planting date (21 May, 9 Jun and 30 Jun) and sub-plots included 15 maize hybrids. The results showed that effect of planting date was significant for plant height, forage yield (P<0.01). Hybrid effect was also significant for all the traits except for dry matter. Planting date and hybrid interaction effect was not significant for most of the traits. Means comparisons for planting dates revealed that second planting date had lower forage yield due to simultaneity of anthesis and silking with high temperature condition in the summer. First and second planting dates had more forage yield. The most ear weight was obtained from the first planting date. Therefore forage from planting in 21 May had more quality and it had more quantity from planting in 30 Jun. means comparisons of hybrids showed that hybrid DKC6589 had the most forage yield.