Insights into the genetics of pre-anthesis tip degeneration and related traits in barley (Hordeum vulgare L.)

Abstract

Pre-anthesis tip degeneration (PTD) in barley (Hordeum vulgare L.) reduces its yield potential by degenerating apical spikelet primordia at early plant developmental stages. The present study explores the natural variation and candidate genes for PTD in 417 six-rowed barleys where it varies from 13 to 51%. Three PTD-QTL are located on chr1H, 3H, and 7H. Chr3H-QTL harbors a candidate gene “barley octotricopeptide repeat protein with α-helical RNA-binding (RAP) domain.” The natural sequence variation within the RAP domain, i.e., I584M substitution, leads to enhanced PTD. The HvRAP TILLING lines show chloroplast structural defects, and decreased spikelet and grain number. Besides, chr1H and 7H harbor putative candidate genes, namely, HvRFL (Restorer-of-fertility-like) and HvRAN2 (Ras-related nuclear protein2), respectively. These findings advance the genetic understanding of PTD and provide key targets for functional validation to increase barley’s yield potential.