Phenology of sunflower cultivars. I. Classification of responses

Abstract

The phenology of commercial sunflower cultivars available to Queensland growers in 1979 was studied in monthly plantings over a 12-month period at Toowoomba in southern Queensland. By using pattern analysis procedures, the cultivars were classified into three maturity groups, viz. 'Very Quick', 'Quick' and 'Medium', based on the number of days from emergence to the head-visible stage of growth. Most of the cultivars belonged to the Quick and Medium maturity groups. Cultivar differences were most obvious for plantings in the cooler months (March to October). To classify new releases, one or two plantings during this period as well as one planting in summer is recommended. Sunfola 68-2 and Hysun 30 should be included in these plantings as cultivars representative of the two major maturity groups. The study showed that there was very little genetic variability in phenology in the present commercial cultivars and there was little difference in phenology among cultivars in the main summer planting period.