تأثير دوره هاي رقابت علف هاي هرز بر عملكرد و برخي از صفات در سه رقم ذرت دانه اي

The Effect of Competition Periods of Weed on Yield and Some Traits in Three Grain Maize Hybrids (Zea mays L.).

In order to investigate the effect of competition periods of weeds on grain yield and some of traits in three maize hybrids, a factorial experiment was conducted at the Agricultural Research Station of Tabriz Islamic Azad University in a randomized complete block design with three replicates during growing season of 2007. Treatments were consisted of weed interference periods at levels (interference at 2-4, 4-6, 6-8 leaf stages, full season weed interference and weed free plot as control) and three maize hybrids (Nos. 504 , 604 and 704). Results showed that the traits such as grain yield, number of kernel rows per ear, ear and cob diameter, were significantly different among hybrids, while the differences among weed interference periods were not significant. Results also indicated that maize and weed biomass at tasseling stage, biological yield and ear length of hybrids, were affected by weed interference treatments significantly. The effect of weed competition on 1000 seed weight was not significant. Biological yield and biomass of hybrids at tasseling stage in full season weed interference treatment were reduced by 25% and 32%, respectively. Hybrid No. 504 producing 5.8 tha1 grain and 11.6 tha1 of biological yield was better than hybrids Nos. 604 and 704. Weed free plots showed better result.