In sunflower, the active leaf area during the grain filling period has been shown to be an important character, which can be used to predict seed yield. Total and residual leaf areas of inbred lines and their hybrids are significantly correlated, but there may be some interaction between parents. Strict sense heritability is moderate. The relation between residual leaf area and seed yield has been confirmed using simplified leaf measurements on recombinant inbred lines and estimation of leaf area index with a ceptometer on hybrids. Studies of use of residual leaf area as a character in breeding for seed yield showed that F2 or F3 plants with the smallest leaf areas can be discarded, but, according to genotype, those with medium or largest leaf area give the best seed yields.
