Insight into the genetic contribution of spikelet development in barley under abiotic stress conditions

Alqudah A. M. and Börner A.

** Resources Genetics and Reproduction, Department Genebank, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, OT Gatersleben D-06466 Stadt Seeland, Germany. 

alqudah@ipk-gatersleben.de

Abstract

Spikelet numbers per spike dramatically reduce during the late reproductive phase that represents half of the maximum yield potential. The molecular genetics of spikelet development and how to keep them alive are not yet studied in barley. Therefore, we studied the developmental process of spikelets and genetic contribution controlling alive spikelet related traits. We characterized 184 diverse barley accessions under field conditions through the developmental process and performed genetic analysis. We developed phenotyping approach to better understand such traits by separating developed and undeveloped spikelets at different developmental stages using portable USB Digital Microscope. We used stat-of-the-art technologyies such as Genotyping-By-Sequencing (GBS) for mapping the novel loci underlying the studied traits. We could use more than 125K SNPs in barley for genome-wide association study and such high dense map had never been used in barley. We also applied the latest bioinformatics approaches e.g. SNP-phenotype network (for the first time in barley), and RNA-Seq expression analysis to detect the most important SNPs and putative candidate genes. Here, we provided the first report about genetic factors controlling spikelet development and its abortion, i.e., novel genomic regions, e.g., on chromosome 7HS. Current work demonstrated the pivotal role of sucrose and phytohormones in spikelet development and keeping them alive. Our findings shed light on the genetic control of alive spikelets that serve as a source of marker-assisted breeding, and a resource for future molecular and genetic validation. We proposed a novel genetic network between spikelet development-related traits and the determinants of boosting grain yield.

​

Keywords: alive spikelet; spikelet development; maximum yield potential; GWAS; barley; candidate genes; sugar-related genes; phytohormones