Detection of QTLs for Yield in Globe Artichoke

The genetics basis of yield-related traits in Cynara cardunculus L. were studied in 115 F₁ progeny derived from an inter-botanical varietal cross between wild cardoon × globe artichoke (Estrella del Sur FCA). The aim of this work was to identify QTLs controlling yield-related traits as a first step to marker assisted selection. Both progenitors and their F₁ were grown at the Experimental Field Station of the Universidad Nacional of Rosario in 2014. Seven agronomic traits were evaluated:number of head per plant (NHP); fresh weight, diameter and length of the main head (WMH, DMH, and LMH, respectively); and fresh weight, diameter and length of the second heads (W2H, D2H, and L2H, respectively). The normal distribution of the traits in the F₁ was verified by a Shapiro-Wilks test. The t-Student test was performed to compare the means values between parents. The correlation between traits was determined by the Pearson coefficient. A total of 247 SSRs (Single Sequence Repeats) were used to evaluate the genotypes. The markers were tested for an expected Mendelian segregation in the F₁ population by a χ2 test. Only SSRs showing a fully consistent with monogenic segregation (χ2 ≤ χ2α = 0.1) were used for QTLs association. Association between SSR locus and traits was determined by a one-way ANOVA (P ≤ 0.05). The proportion of total phenotypic variance explained by each QTL was estimated by R² values. All the morphological traits showed normal distribution (Sh-W > 0.94) and the parental genotypes were significantly different for one to another for all traits analyzed. The correlation analysis revealed that diameter and length of the main or secondary heads were the most important factors influencing fresh weigh. A total of 70 SSRs showed Mendelian segregation and were used for QTLs association. Eleven SSR markers were linked to 22 QTLs and six of them showed association with more than one trait. Three SSRs were associated with WMH, three with DMH, five with W2H, eight with D2H and three with L2H. The percentage of total phenotypic variation explained by each QTLs ranged from 6% to 18%. This work provides evidence that there are several loci controlling globe artichoke yield and the SSR linked to yield-related traits should be used for marker-assisted improvement of the species.