title: Unravelling the genetic complexity of sorghum seedling development under low-temperature conditions.
abstract: Sorghum is a promising alternative to maize for bioenergy production in Europe; however, its use is currently limited by poor adaptation to low temperatures during and after germination. We collected multi-trait phenotype data under optimal and suboptimal temperatures in a genetically diverse recombinant inbred line (RIL) mapping population showing contrasting segregation patterns for pre- and post-emergence chilling tolerance. Germination, emergence, seedling development, root architecture and seedling survival were assessed in two different seedlots. Emergence and root establishment were found to be the key determinants of development and survival under chilling stress. Highly interactive epistatic quantitative trait loci (QTL) hotspots, including a previously unknown QTL on Sb06 with a significant effect on prolonged chilling survival, were found to regulate different physiological mechanisms contributing to maintenance of growth and development despite the chilling temperatures. The major QTL regions harbour promising candidate genes with known roles in abiotic stress tolerance. Identification of loci in the QTL hotspot regions conferring maintenance of cell division and growth under early chilling stress represents a promising step towards breeding for successful establishment of sorghum in temperate climates.
authors.affiliation: Department of Plant Breeding, Justus Liebig University, Giessen, 35392, Giessen, Germany.
authors.forename: Wubishet A
authors.initials: WA
authors.lastname: Bekele
authors.forename: Karin
authors.initials: K
authors.lastname: Fiedler
authors.forename: Amukelani
authors.initials: A
authors.lastname: Shiringani
authors.forename: Daniel
authors.initials: D
authors.lastname: Schnaubelt
authors.forename: Steffen
authors.initials: S
authors.lastname: Windpassinger
authors.forename: Ralf
authors.initials: R
authors.lastname: Uptmoor
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Friedt
authors.forename: Rod J
authors.initials: RJ
authors.lastname: Snowdon
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000528:radiation effects; D002874:Chromosome Mapping; D016000:Cluster Analysis; D003080:Cold Temperature; D003433:Crosses, Genetic; D017343:Genes, Plant / Q000235:genetics; D056726:Genetic Association Studies; D005858:Germany; D018525:Germination / Q000235:genetics / Q000528:radiation effects; D007178:Inbreeding; D008027:Light; D016014:Linear Models; D010802:Phylogeny; D040641:Quantitative Trait Loci / Q000235:genetics; D019655:Quantitative Trait, Heritable; D011995:Recombination, Genetic / Q000235:genetics; D036226:Seedlings / Q000235:genetics* / Q000254:growth & development* / Q000528:radiation effects; D045868:Sorghum / Q000235:genetics* / Q000254:growth & development* / Q000528:radiation effects; D013312:Stress, Physiological / Q000235:genetics / Q000528:radiation effects
keywords: QTL; abiotic stress; chilling; low temperature; sweet sorghum