Yield and quality response of autumn-planted sunflower (Helianthus annuus L.) to sowing dates and planting patterns

Sowing time and sowing methods are often used to overcome environmental constraints on crop production. Information on the effect of these agronomic techniques on sunflower (Helianthus annuus L.) oil quality is, however, scarce. A field study was conducted to evaluate the effect of sowing dates and planting patterns, and their interaction, on seed yield and oil quality of hybrid sunflower. Sunflower hybrid Hysun-33 was sown at four dates beginning with the first week of August with fortnightly intervals under three planting patterns, viz., flat sowing (60 cm apart lines), ridge sowing (60 cm apart ridges) and bed sowing (90/30 cm) for 2 yr (2002 and 2003). The performance of the August sowing dates was significantly better with respect to yield and yield components than the September-sown crop. Among the three sowing dates in August, there was variable performance of the crop in the 2-yr study. On average, the sowing of sunflower from mid-August to the last week of August yielded better than early August sowing dates. The evaluation of quality parameters revealed greater content of achene oil in the September-sown crop followed by the crop sown in the last week of August. Delayed sowing lowered oleic acid content, but increased stearic and linoleic acid levels. Planting pattern treatments affected head diameter, achenes per head, 1000-achene weight and achene yield. Conclusively, sunflower sown on ridges during the second fortnight of August encountered favourable environmental conditions and gave significantly higher economic yield.