Cold tolerance during juvenile development in sorghum: a comparative analysis by genomewide association and linkage mapping

Abstract

Improved cold tolerance during the juvenile phase is a major breeding goal to develop new sorghum cultivars suitable as an alternative energy crop in temperate regions. The objectives of this study were to identify marker‐trait associations for cold tolerance in a sorghum diversity panel fingerprinted with 2620 single nucleotide polymorphism (SNP) markers and to detect quantitative trait loci (QTL) in two F2:3 populations. Traits of interest were dry matter growth rate (DMGR), leaf appearance rate (LAR), chlorophyll content (SPAD) and chlorophyll fluorescence (Fv′/Fm′ and ФPSII) in relation to temperature. The association panel comprised 194 genotypes, while the F2:3 populations consisted of 80 and 92 genotypes. All populations were tested under controlled conditions in a minimum of four temperature regimes ranging from 9.4°C to 20.8°C. QTL were identified for means across environments and regression parameters describing temperature effects. Several marker‐trait associations for mean (m) DMGR, base temperature (Tb) of SPAD and ФPSII and temperature effect on LAR were validated by QTL detected in population 1 or 2. Promising QTL regions were found on chromosomes SBI‐01, SBI‐02, SBI‐03, SBI‐04, SBI‐06 and SBI‐09, among them genomic regions where candidate genes involved in the C‐repeat binding pathway or encoding cold‐shock proteins are located.

Differentially regulated orthologs in sorghum and the subgenomes of maize

“…After one day of cold stress, the species can be broadly classified as either cold stress insensitive or cold stress sensitive with both maize and sorghum in the cold stress sensitive category. A longer period of cold stress (3 days) demonstrated greater impairment of CO 2 assimilation rates in sorghum than in maize, consistent with previous reports on the relative cold sensitivity of these two species (Chinnusamy et al, 2007;Chopra et al, 2017;Fiedler et al, 2016;Hetherington et al, 1989;Wendorf et al, 1992). S1).…”

Differentially Regulated Orthologs in Sorghum and the Subgenomes of Maize

“…After 1 d of cold stress, the species could be broadly classified as either cold stress insensitive or cold stress sensitive, with both maize and sorghum in the cold stress sensitive category. A longer period of cold stress (3 d) revealed greater impairment of CO 2 assimilation rates in sorghum than in maize, consistent with previous reports on the relative cold sensitivity of these two species (Chinnusamy et al, 2007;Chopra et al, 2017;Fiedler et al, 2016;Hetherington et al, 1989;Wendorf et al, 1992) and separated the six species into three broad categories of cold tolerant, moderately cold sensitive and extremely cold sensitive. Based on these data, we selected one day of cold stress, when maize and sorghum still exhibit comparable levels of CO 2 assimilation impairment ( Figure 2D), for downstream expression analysis.…”

Sorghum as a Novel Crop for Central Europe: Using a Broad Diversity Set to Dissect Temperate-Adaptation

“…Our results (Table S4) confirm juvenile cold tolerance of sorghum being a highly quantitative trait with multiple physiological pathways involved, as already shown in previous studies [19,22,53]. Most of the QTL described in these studies lie nearby genes involved in the anthocyanin and carbohydrate metabolism.…”

“…Several studies have aimed at the identification of quantitative trait loci (QTL) for a better understanding of the physiological mechanisms behind chilling tolerance related traits, either in bi-parental populations [10,16,17] or diversity sets: 194 biomass lines from KWS company (Einbeck, Germany) [7,[18][19][20]; 242 accessions of the ICRISAT (International Crops Research Institute for the Semi-Arid Tropics) sorghum mini core collection [21]; 136 sorghum accessions from cooler regions of the world [14]; and 300 sorghum accessions from the U.S. sorghum association panel [22]. Genomic regions influencing traits of interest have been concordantly confirmed in these studies.…”