SUMMARY
Effect of different row directions on yield and yield components of sunflower (Helianthus annuus L.) was studied in a field experiment at National Agricultural Research Center, Islamabad, Pakistan, during spring 1991 and 1992. Four row directions, i.e., north-south (NS), east-west (EW), north eastsouth west (NESW) and north west-south east (NWSE) had very little effect on seed yield and other agronomic characters of sunflower. The differences in the mean plant height, head diameter, seed yield, 100-achene weight and fatty acid profile were statistically non-significant. Trends were similar in both years. As an average of the two years, although statistically non-significant, the highest seed yield of 3065 kg/ha was obtained from north east-south west (NESW) row direction and the lowest yield of 2624 kg/ha from east-west (EW) row direction. The most pronounced effect of row direction was noted on seed moisture content. As an average of the two years, the maximum seed moisture content at harvest (21.4%) was obtained from east-west (EW) row direction and the minimum (14.6%) from north-south (NS) row direction. NESW row direction also gave significantly lower moisture content (15.1%) than EW (21.4%) and NWSE (18.1%) row directions. Therefore, using north-south and NESW row directions would help the crop to dry more quickly before harvest and reduce post harvest costs and losses. Seed production fields that require examination of sunflower heads to detect pollen production should be planted in NS rows for efficient roguing to maintain genetic purity. For research plots, EW rows with plot labels on the east end are often preferred, because it is easier to evaluate most plots when all heads face the viewer.