Effects of boron application on the physiological potential of stored sunflower seeds

The objective of this study was to assess the physiological quality of sunflower seeds as a function of boron rates and seed storage times. The experiment was conducted at the Seed Laboratory of the State University of Goias, Ipameri campus, Goias, Brazil. A completely randomized experimental design was used, in a 6x6 factorial arrangement, with four replications. The factors consisted of six boron rates (0, 1, 2, 3, 4, and 5 kg ha-1) manually applied to the soil using boric acid (17%), and six seed storage times (0, 2, 4, 6, 8, and 10 months). The seeds used were from plants grown in 2017 as a second crop, which was fertilized according to the boron treatments. The following evaluations were conducted after harvesting for each seed storage time: germination test, first germination count, accelerated aging test, total germination, seed moisture content, seedling length and dry weight, 1,000-seed weight, and tetrazolium test. Boron rates and storage times had positive effects on most analyzed variables. The most adequate boron rate found was 2 to 3 kg ha-1, with no effect of seed storage times on the physiological quality of sunflower seeds.