QTL Analysis for Chlorophyll Content in Strawberry (Fragaria × ananassa Duch.) Leaves

Chlorophyll is an important factor facilitating plants to capture, allocate and transforms light energy and plays a major role in yield formation. Strawberry is one of the most important fruit crops worldwide. Breeding strawberry for better light utilization by improving photosynthetic efficiency can improve the yield potential. In strawberry, genetic studies have been done for several traits, but no reports on the genetic mapping of chlorophyll content in leaves. In the present study, we used two independent F2 mapping populations (BS-F2 and BC-F2) and, Axiom 35 K strawberry chip and genotyping-by-sequencing derived single nucleotide polymorphisms based linkage maps to identify the quantitative trait loci (QTLs) controlling leaf chlorophyll content. SPAD values were used to estimate the leaf chlorophyll content of parental lines and F2 populations. A total of seven QTLs, including major and minor effects, common and specific to populations, were identified across the strawberry genome explaining phenotypic variation (R2) ranging from 1.4 to 26.4%. Candidate genes associated with the photosynthesis and chlorophyll content were inferred in commonly detected QTLs. This work thus provides not only information for novel loci controlling chlorophyll content in strawberry leaves but also forms the basis for future marker assisted breeding in strawberry to select the plants for required chlorophyll content.