The experiment was carried out in Passo Fundo-RS, Brazil, in order to evaluate the interaction between cultivars and planting dates for corn yield and yield components. The experiment was conducted under irrigated, during the 1991/92 growing season. Two planting dates (September 13, 1991 and January 3, 1992) and nine com cultivars (C 805, C 901, P 3069, SR 100, AG 303, AG 513, XL 560, XL 605 and G 5555) were tested. Plants were harvested on March 4, 1992 and May 26, 1992 for the planting dates of September and January, respectively. There were differences in the grain yield and yield components among the cultivars for the two planting dates tested. In September, the sowing of the C 901 and C 805 cultivars showed the highest grain yield. In January, the cultivar C 901 showed the highest grain yield. The average grain yield varied from 9.69t ha-1, in the first planting date to 4.05t ha-1 in the second planting date. The average grain yield was reduced in 58.2%. from the first to the second planting date. The grain yield decreased more than 60% in XL 560, P 3069 and SR 100 cultivars as a result of the delay in the planting date. The sowing in September favoured more kernel weight and number of kernels per ear than the sowing in January.
planting dates; cultivars interaction; yield potential; kernel weight
