ChileanJAR

At Quilamapu Research Station oflhe Institutodelnvestigaciones Agropecuarias (INlA) six trials under field condttions were carried out during 1987 to 1990, to measurethe effects of three row spacing (10, 20 and 30 cm) and three seeding rate (80, 160 and 240 kg/ha) on grain yield and yield components in two wheat varieties (Triticum aestivum L.). Each experiment was conducted as split plot experimental design with four replications. Row spacing were the main plots and seed ing rate the subplots. Yield ofwinter variety Laurel-INIA was not affected by seeding rates used; however yield of spring variety Ciko-INIA was significantly higher at seeding rates of 160 and 240 kg/ha compared with 80 kg/ha. A though the narrow row spacing tended to yield higher than wider spacing, significant differences were observad only in one winter trial and two spring trials. The yield component most affected by changes in row spacing and seeding rates was the number of spikes by m² .