Influence of Sowing Date On Growth and Yield Components of Sunflower (helianthus Annuus L.) in Semi-arid Zone - Influence of Sowing Date On Growth and Yield Components of Sunflower (helianthus Annuus L.) in Semi-arid Zone - Open Access Pub

The main objective of this study was to quantify the influence of sowing date on growth and yield components of hybrid sunflower (Hysun33) cultivar in semi-arid zone. This experiment was conducted during the seasons 2014/2015-2015/2016 at the farm of the College of Agricultural Studies, Sudan University of Science and Technology, Shambat, Khartoum- Sudan. The experiment was arranged in randomized complete block design (RCBD) with four replications and three treatments. Different parameters were considered including plant height, leaf area index (LAI), filled sees number/head, head diameter, dry weight and yield components. The collected data were statistically analyzed. The results revealed that crop sown in May and July showed significant increase in plant height, LAI, head diameter, dry weight, field seed number/head, weight of 100 seeds; yield; and yield components; compared to crop sown in March. However, crop sown in the second season showed an increase in growth and yield components compared to the crop of the first season. DOI10.14302/issn.2639-3166.jar-19-2961 Sunflower (Helianthus annuus L.) belongs to family Compositeae. It is a native to Central America, and seemingly; it is Peruvian or Mexican in origin 1, 2. The economic importance of this crop is that the fresh green plant can be used as silage or fodder to feed livestock. The seed can be eaten raw or roasted, and it can be used in salads, cooking, margarine, lubricant, paint varnishes and soap production. The seed contains about 36 to 45 % oil depending on the variety 3. The crop is categorized as a low to medium drought sensitive 4. It shows adaptability to different regions, climatic conditions and sowing dates due to its high genotype and ambient interactions 5. Therefore it can be grown twice a year 2. Nevertheless, despite the ability of the crop to high water use, and the ability to withstand short periods of severe soil water deficit of up to 15 atmosphere tension, the long periods of severe soil water deficit, particularly at water-sensitive growth stages, causes significant reduction in seed yield 6. It is noticed that good cultural practices and drainage are required for sunflower production 7. However; several studies reflected that sunflower can be grown at a wide range of dates. Most cultivars are early maturing. In areas where no winter, sunflower can be grown at any month of the year to obtain satisfactory yields 8, 9. It is reported that yield differences between hybrids with regard to sowing time and density are remarkable. These differences are determined on one hand by