Improved yield potential is the goal of barley domestication and cultivation. During this process, two- and six-rowed barley types emergedand have been utilised in breeding and production. The six-rowed type could produce three times as many grains as its ancestral two-rowed forms, thus dominating barley cultivation for thousands of years. The deficiensform of the two-rowed type, characterised by extremely suppressed lateral spikelets, has gained dominance over the past few decades in barley-growing regions worldwide. We hypothesised that the absence of lateral spikelets in deficiensbarley affects spike architecture and spike-related traits, contributing to its superior yield potential of deficiensbarley cultivation. Currently, a deficiensbarley variety, RGT Planet, is the most popular barley variety in the world. In this study, we used two F₂populations derived from crossing RGT Planet with two canonical two-rowed barley and identified the functional allele Vrs1.t1associated with deficiensmorphology. We observed that the Vrs1.t1allele may contribute to high yield potential by optimising spike architecture through increased spikelet length, grain number, and grain size. Phylogenetic analysis suggests that the deficiensmutation was likely present from the early stages of barley cultivation in the Fertile Crescent and spread to Ethiopia and beyond with agricultural expansion. We conclude that the ancient deficiensallele Vrs1.t1has been a critical driver for the recent success of modern barley improvement by optimising spike architecture.

functional genes  /  Aspergillus  /  aflatoxin  /  development