Evaluation of the Response of Oilseed Sunflower Pure Lines (Helianthus annuus L.) Under Phosphorus Deficiency Condition

Phosphorus is one of the most nutrient elements in plants that has multiple structural roles in the cell and catalytic function of the enzymes involved in metabolism. Due to low phosphorus availability in calcareous soils and differences in plant genotypes in soil phosphorus uptake, identification and study of different genotypes with high phosphorus uptake efficiency is essential to reduce the use of chemical fertilizers. For this purpose, 76 pure sunflower lines collected from different parts of the world were investigated in two separated optimum and phosphorus deficiency conditions based on completely randomized design with three replications in Faculty of Agriculture research field, Urmia University during 2017 cropping season. In optimum condition, 0.4 g/kg triple superphosphate was added to the soil with deficient phosphorus content (7.24mg/kg) in each pot. Significant difference was observed at 1% probability level for all investigated traits including plant height, stem diameter, head diameter, thousand seed weight, grain yield and percentage of phosphorus. Oilseed sunflower lines were clustered into four clusters under both optimum and phosphorus deficiency conditions. The distribution of investigated lines in the same clusters was different under optimum and phosphorus deficiency conditions. Finally, based on the biplot of MFVD multivariate tolerance index, principal component analysis and the result of cluster analysis lines 6, 72, 71, 19, 35 were identified as desirable lines. These lines showed high grain yield and yield components and lower reduction under phosphorus