The cultivated strawberry (
Fragaria
×
ananassa
Duch.) is an economically important fruit crop. Improvement of fruit quality is a major breeding objective. Although numerous quantitative trait loci (QTLs) have been identified for fruit‐related traits, less information is available on quality attributes such as fruit mass, total soluble solids (TSS) and susceptibility to water soaking (WS). The objective of our study is to identify and validate genetic regions associated with fruit mass, TSS and WS susceptibility using a model population derived from an interspecific cross between
F
. ×
ananassa
and
Fragaria chiloensis
. Phenotyping was conducted in three seasons, and QTL analysis was performed using an already existing linkage map consisting of 2990 SNP markers. The introgression of the wild‐type
F. chiloensis
resulted in a decrease in fruit mass and an increase in fruit TSS. Annual broad‐sense heritabilities
H
2
indicated that the expression of all three traits is affected by genetic but also by environmental factors (
H
2
ranging from 0.27 to 0.68). Multiple QTLs for each trait were identified, with significant QTLs explaining up to 27% of the phenotypic variation. For TSS content, QTLs on linkage group 1C, 3A and 4A; and for WS susceptibility, QTLs on linkage group 1B, 1C, 4A and 6D were stable in at least two seasons. None of the QTLs was stable for fruit mass. This study confirmed the polygenic and complex nature of fruit mass, TSS and WS susceptibility. Some regions involved in these traits could be validated in our study, thus providing useful insights for breeding of cultivars with improved fruit mass, TSS content and tolerance against WS.
Diana Seidler, Grecia Hurtado, Moritz Knoche et al.· Plant Breeding· 0 citations
Water availability is a major constraint for intensive crops such as strawberry (Fragaria × ananassa), yet the genetic, physiological and molecular basis of water use efficiency remains poorly understood. Here, we evaluated a diverse collection of 132 accessions under well-watered (WW) and water-limited (WL) conditions (40% reduced irrigation) to dissect variation in leaf-level water use efficiency (WUEL), agronomic performance, and fruit quality. Substantial phenotypic variation was observed across 25 traits. Under WW conditions, lower stomatal density was associated with higher WUEL, yield, fruit weight, and firmness, suggesting a favorable carbon–water balance. Population structure analysis revealed that modern and exotic cultivars combine higher WUEL and agronomic performance with reduced stomatal density, suggesting an indirect selection during breeding. Genome-wide association studies detected 25 marker–trait associations for 11 traits, with all but one specific to water regime, highlighting a complex genetic architecture and important environmental effects. Transcriptomic analysis of accessions contrasting in stomatal density and WUEL identified 4837 differentially expressed genes and revealed two distinct strategies underlying water management: (1) an energy-conservative strategy characterized by reduced stomatal density and higher WUEL, enhanced ABA signaling and optimized photosynthetic electron transport; and (2) an energy-demanding strategy associated with higher stomatal density and lower WUEL, increased autophagy, activated stress-mitigating pathways and higher investment in secondary metabolism. Together, these results provide the first integrated phenotypic, genetic and molecular characterization of WUEL in octoploid strawberry and identify candidate loci and pathways, thereby establishing a foundation for improving WUEL-related traits.
Mario Ruiz-Velázquez, Cristina Castillejo, J. F. Sánchez-Sevilla et al.· Horticulture Research· 0 citations