title: Genetic analysis of proline concentration under osmotic stress in sunflower (Helianthus annuusL.).
abstract: Proline concentration has been often suggested as an indicator of osmotic stress. A better understanding of the genetics of this trait is however needed. In the present study, proline concentration has been assessed, together with root and stem growth, potassium, calcium and total soluble sugars concentration and stress injury symptoms, in seedlings of sunflower hybrids and their parents grown under control and osmotic conditions. Proline strongly accumulated with osmotic stress. Its concentration exhibited a large variation among genotypes and was higher in hybrids than in parental lines. A positive association was noted between proline concentration and osmotic adjustment that was reflected in a reduction of osmotic stress induced injury, as showed by the reduced number of calli in the hybrids with higher proline concentration. Broad and narrow sense heritability was higher under osmotic stress suggesting applying the selection in osmotic stress condition. In the control treatment, dominance effects explained most of the genetic variation for proline concentration while under osmotic stress both dominance and additive variance were high. The importance of dominance and additive effects suggested that several genomic regions are controlling this trait. Good general combiners, presumably carrying positive additive alleles affecting proline concentration, were identified.
authors: Department of Plant Breeding & Genetics, University College of Agriculture, University of Sargodha , Pakistan.
authors: Farghama
authors: F
authors: Khalil
authors: Department of Plant Breeding & Genetics, University College of Agriculture, University of Sargodha, Pakistan; Plant Tissue Culture Lab, University College of Agriculture, University of Sargodha, Pakistan.
authors: Saeed
authors: S
authors: Rauf
authors: International Potato Center (CIP) , Avenida La Molina 1895, La Molina, Lima , Peru.
authors: Philippe
authors: P
authors: Monneveux
authors: Department of Plant Breeding & Genetics, University College of Agriculture, University of Sargodha , Pakistan.
authors: Shoaib
authors: S
authors: Anwar
authors: Plant Tissue Culture Lab, University College of Agriculture, University of Sargodha, Pakistan; Department of Plant Pathology, University College of Agriculture, University of Sargodha, Pakistan.
authors: Zafar
authors: Z
authors: Iqbal
keywords: additive effect; dominance effect; gene action; heritability; heterosis; osmotic adjustment; proline concentration