Document Type : Research Paper
1 Department of Plant Breeding and Biotechnology, Urmia University, Urmia, Iran.
2 Institute of Biotechnology, Urmia University, Urmia, Iran.
Many agriculturally important traits are complex, affected by many genes and the environment. Quantitative trait loci (QTL) mapping is a key tool for studying the genetic structure of complex traits in plants. In the present study QTLs associated with yield and agronomical traits such as leaf number, leaf length, leaf width, plant height, stem and head diameter were identified by using 70 recombinant inbred lines (RILs) from the cross (♀) PAC2 × RHA266(♂). RILs and their parents were evaluated in a rectangular 8´9 lattice design with two replications. High genetic variability and transgressive segregation were observed in all studied traits. Genetic gain representing the difference between 10% of selected RILs and their parents was significant for most of the studied traits. Positive and significant genotypic and phenotypic correlations were observed among the studied traits. QTL analysis was performed using a recently developed SSR and SNP sunflower linkage map. The map consists of 210 SSRs and 11 SNP markers placed in 17 linkage groups (LGs). The total map length is 1,653.1 cM with a mean density of 1 marker per 7.44 cM. Composite interval mapping (CIM) procedure detected 21 QTLs involved in genetic control of studied traits. The phenotypic variance explained by the identified QTLs varied from 1.13 to 73.70%. QTLs such as HMBPP associated with the expression of more than one trait could increase the efficiency of marker-assisted selection (MAS) and genetic progress in sunflower.