Temporal profiling of meiotic asynchrony between florets for wheat-fertility studies

Abstract

Wheat grain number integrates fate of individual florets, strongly affected by environmental stress during sensitive stages like meiosis. Because development is asynchronous across tillers, spikelets, and florets, it is hard to distinguish true stress tolerance from stress escape. Based on morphological and destructive measurements of spike and anther length in four controlled-environment experiments, we developed a framework to track all floret developmental stages at plant level, and particularly meiosis. We applied this framework in two case studies for connecting within-plant developmental asynchrony to reproductive success under favorable and heat stress conditions. All florets showed a common relative growth rate, producing stable and additive developmental delays across tillers, spikelets, and floret positions. This generated a developmental map for every floret based on simple external traits. Under favorable conditions, grain set probability at floret level combined both positional and developmental effects within a spike. Under heat stress, grain loss occurred only in florets at meiosis during the stress, allowing to quantify a true "stress response", while later florets escaped damage. This framework offers a quantitative tool to understand and predict floret development and link it to grain set, clearly distinguishing timing effects from positional influences and separating true tolerance from stress escape.

Plant phenotyping relevance

小花の発達段階を形態測定から追跡・推定する定量的フレームワークを開発し、植物体レベルで検証・適用しているため、表現型取得法が中心的です。

Code and data availability

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