Selection of sunflower cultivars for boron efficiency using nutrient solution

Boron deficiency is common in Brazilian soils specially under Savanna conditions. Sunflower crop is very demanding as to boron supply, showing low tolerance to its deficiency. This research was done to screen sunflower cultivars for high boron utilization efficiency based on relative plant reaction in complete (0.15 mg B L -1 ) and deficient (0.00625 mg B L -1 ) nutrient solution. Twenty-two cultivars were evaluated in three independent assays, according to a randomized complete block design with six replicates. Root growth, plant height, leaf length, fresh root weight, fresh canopy weight, and symptoms of boron deficiency were evaluated. A criteria of efficiency and responsiveness was established. The selection procedure was efficient for root and canopy fresh weights, plant height and root growth, and allowed the selection of superior sunflower genotypes such as the AS 238 and AS 243 cultivars.