Raw data: Spikelet stop determines the maximum yield potential stage in barley

Determining the grain yield potential contributed by grain number is a
step towards advancing cereal crops' yield. To achieve this aim, it
is pivotal to recognize the maximum yield potential (MYP) of the crop. In
barley (Hordeum vulgare L.), the MYP is defined as the maximum spikelet
primordia number of a spike. Previous barley studies often assumed the awn
primordium (AP) stage as the MYP stage regardless of genotypes and growth
conditions. From our spikelet-tracking experiments using the two-rowed
cultivar Bowman, we found that the MYP stage can be different from the AP
stage. Importantly, we find that the occurrence of inflorescence meristem
(IM) deformation and its loss of activity coincided with the MYP stage,
indicating the end of further spikelet initiation. Thus, we recommend
validating the barley MYP stage with the IM's shape and propose this
approach (named Spikelet Stop) for MYP staging. Following this approach,
we compared the MYP stage and the MYP in 27 two- and six-rowed barley
accessions grown in the greenhouse and field. Our results reveal that the
MYP stage can be reached at various developmental stages, which majorly
depend on the genotype and growth conditions. Furthermore, we found that
two-rowed barleys’ MYP and the duration reaching the MYP stage may
determine their yield potential. Based on our findings, we suggest key
steps for the identification of the MYP in barley that can also be applied
in a related crop such as wheat.