Stephanie M. Brunner,Eric Dinglasan, Silvina Baraibar, Samir Alahmad, Christina Katsikis, Sarah van der Meer, Jayfred Godoy, David Mood, Millicent Smith, Lee Hickey, Hannah Robinson

Theoretical and Applied Genetics;  June 2024; Volume 137, article number 120

Key message

There is variation in stay-green within barley breeding germplasm, influenced by multiple haplotypes and environmental conditions. The positive genetic correlation between stay-green and yield across multiple environments highlights the potential as a future breeding target.

Abstract

Barley is considered one of the most naturally resilient crops making it an excellent candidate to dissect the genetics of drought adaptive component traits. Stay-green, is thought to contribute to drought adaptation, in which the photosynthetic machinery is maintained for a longer period post-anthesis increasing the photosynthetic duration of the plant. In other cereal crops, including wheat, stay-green has been linked to increased yield under water-limited conditions. Utilizing a panel of diverse barley breeding lines from a commercial breeding program we aimed to characterize stay-green in four environments across two years. Spatiotemporal modeling was used to accurately model senescence patterns from flowering to maturity characterizing the variation for stay-green in barley for the first time. Environmental effects were identified, and multi-environment trait analysis was performed for stay-green characteristics during grain filling. A consistently positive genetic correlation was found between yield and stay-green. Twenty-two chromosomal regions with large effect haplotypes were identified across and within environment types, with ten being identified in multiple environments. In silico stacking of multiple desirable haplotypes showed an opportunity to improve the stay-green phenotype through targeted breeding. This study is the first of its kind to model barley stay-green in a large breeding panel and has detected novel, stable and environment specific haplotypes. This provides a platform for breeders to develop Australian barley with custom senescence profiles for improved drought adaptation.

See https://link.springer.com/article/10.1007/s00122-024-04612-1

Figure 1: Population structure and genetic diversity of the barley breeding panel (n = 397). Principal component analysis was performed based on Roger’s distance and calculated using 6734 SNPs. The three distinct clusters are displayed in different colors. A subset of barley cultivars are labelled