AUTHOR=Ntawuguranayo Simeon , Zilberberg Michael , Nashef Kamal , Bonfil David J. , Bainsla Naresh Kumar , Piñera-Chavez Francisco J. , Reynolds Matthew Paul , Peleg Zvi , Ben-David Roi 

TITLE=Stem traits promote wheat climate-resilience

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1388881

DOI=10.3389/fpls.2024.1388881

ISSN=1664-462X

ABSTRACT=Grain filling under a range of post-anthesis stress scenarios can depend heavily on the capacity and remobilization of stem water-soluble carbohydrates (WSC). To identify specific stem traits that reliably reflect the relationship between WSC and grain yield and kernel weight, a diverse panel of semi-dwarf spring wheat advanced lines was selected for natural variations in stem traits (WSC content, stem diameter, peduncle length, and stem wall width). Lines were phenotyped under various environmental conditions: well-watered, water-limited, and heat stress in Mexico, and terminaldrought (Mediterranean rain-fed) in Israel. Environmental stresses resulted in reduced grain yield (from 626 g m -2 under well-watered to 213 g m -2 under heat), lower internode diameter, and peduncle length. However, stem-WSC generally peaked 3-4 weeks after heading under all environments except heat (where it peaked sooner) and expressed the highest values (mg g -1 ) under water-limited and terminal-drought environments. Increased investment in internode diameter and peduncle length were associated with a higher accumulation of stem WSC, which showed a positive association with yield and kernel weight. Across all environments, there were no apparent trade-offs between increased crop investment in internode diameter, peduncle length, and grain yield. Results show that genotypes that invest relatively more resources in stem structural biomass and WSC accumulation & remobilization can be a valuable strategy to ameliorate grain size reduction under stress without compromising grain yield potential. Furthermore, easy-to-measure proxies for WSC (stem diameter at specific internodes and length of the last internode, i.e., the peduncle) could significantly increase throughput, potentially at the breeding scale.