Association genetics of early season cold and late season frost
tolerance in Sorghum bicolor
Abstract
Sorghum is known as camel among the crops, grown worldwide for food,
fodder, and fuel. However, sorghum is highly susceptible to low
temperature stress, which greatly affects seed germination, seedling
vigor, root architecture, level of cyanogenic glycosides, fertility, and
grain yield. Adaptation to low temperature is very crucial for achieving
desirable yields under temperate conditions. Here, an association
mapping study was conducted using the large global sorghum diversity
germplasm accessions to delineate the genetics of early season cold
(ESC) and late season frost (LSF) tolerance in sorghum. A total of 10
single nucleotide polymorphisms (SNPs) and 17 quantitative trait loci
(QTLs) were identified for ESC and 40 SNPs were identified for LSF. Two
ESC tolerance QTLs identified from our study were co-localized with the
classical tannin genes Tan1 and Tan2. This study identified probable
candidate genes: Sobic.001G157100 (NPH3), Sobic.001G156600 (Lectin
receptor-like serine/threonine kinase), and Sobic.006G061100 (SnRK1
gamma sub-unit) as for ESC tolerance and Sobic.006G139900
(UDP-glucoronosyl and UDP-glucosyl transferase), Sobic.002G187400
(Serine/threonine protein kinase), and Sobic.004G333700
(Ca2+/calmodulin-dependent protein phosphatase) for LSF tolerance in
sorghum. The identified candidate genes were known to play a major role
in seed germinability under cold stress and involved in plant signal
transduction and regulation of cold and other biotic and abiotic
stresses in crop plants.