LUSH SPIKE – Towards the Genetic and Molecular Elucidation of Spikelet Survival in Barley

Improving grain yield is a major objective of crop breeding, and a promising avenue for maximizing yield through enhanced spikelet survival during pre-anthesis development. However, little is known about spikelet survival and its impact in grain yield in cereals. In barley, the number of spikelet primordia per spike at the awn primordium (AP) stage represents the maximum yield potential per spike. The growth period AP to tipping (TIP) is considered as the most critical pre-anthesis phase determining spikelet primordia abortion and grain yield since ~70% of spikelet abortion occurs during this phase, regardless of growth conditions and row-type. Mortality of spikelet primordia begins with the onset of rapid stem and spike growth and lasts until heading. Interestingly, the high broad-sense heritability (>80%) of spikelet survival in barley underscores that there are major genetic players regulating this trait. Therefore, we aim to discover QTL for spikelet survival in a GWAS panel and validate them in bi-parental double haploid (DH) mapping populations. Furthermore, interesting QTL will be mendelized, functionally characterized, and the underlying gene will be identified using a map-based approach. The genetic analysis of spikelet survival will be complemented with gene regulatory network analysis during the most critical pre-anthesis period. Finally, the spatio-temporal patterns of transcript, metabolite and phytohormone distribution/modulation in the spike may illustrate the mechanistical regulation of spikelet survival.