تستر X تجزيه ژنتيكي عملكرد و برخي از صفات فتولوژيكي در لاين هاي آفتابگردان تحت شرايط نرمال و تنش خشكي با استفاده از طرح تلاقي لاين

Genetic Analysis of Yield and Some Phonological Traits in Sunflower Lines Under Normal and Drought Stress Conditions Using Line x Tester Mating Design

In order to evaluate and select the drought tolerant sunflower hybrids and their parents, two experiments were conducted under stress and non-stress conditions in the form of linex tester design at the Seed & Plant Improvement Research Institue of Karaj, Iran, in 2002. Both experiments consisted of 36 treatments including 3 lines with cytoplasmic male sterility, 8 restorers and 24 their hybrids and one open-pollinated variety (Armaviruski). The experimental design was a simple lattice design with two replications. All plots in stress and non-stress conditions were irrigated on the basis of 180mm and 60mm class A evaporation pan, respectively. Drought stress was applied at 6-8 leaf stage. Analysis of variance showed all traits were highly significant in stress and non-stress conditions. To study combining ability, linex tester analysis was used using procedures developed by Kempthorne (1951), Singh and Chaudhari (1976). Line mean square for traits such as seed filling period, days to the beginning and end of flowering and tester mean square for traits such as seed filling period and days to physiological maturity were singificant under two conditions, which shows additive variance is singificant. Where as linex tester mean square for traits such as seed filling period, days to the begining and end of flowering and days to Reproductive Stage 8 was significant under one/two conditions; which shows that non-additive variance is singificant. GCA/SCA variance ratio revealed that non-additive genetic variance was more important than additive variance for latter traits.