Rice yield responses to high temperature and agronomic adaptation options: A meta-analysis and regional evaluation of sowing-date adjustment

Abstract

High-temperature (HT) stress threatens global rice production, yet the comparative efficacy and synergistic potential of agronomic adaptation strategies remain poorly quantified. Here, we integrated 4044 observations from 106 publications across 11 countries, evaluating the individual effects of cultivar replacement, exogenous application of plant growth regulators (PGRs), fertilization optimization (CF), and sowing-date adjustment (ASD) via multilevel models, and separately conducted a 1980–2024 spatiotemporal analysis across six regions in the Yangtze River Basin. Globally, HT reduced grain yield by 42.3% (lnRR = −0.55; 95% CI: −0.73 to −0.37), driven by a 16–26% decline in seed-setting rate (SSR) depending on type, with field trials showing larger effect than pots (e.g., hybrid rice: −9.98% vs. −1.22% for yield). All four strategies alleviated yield losses, with CF (+48%, lnRR = 0.39; 0.16–0.62) and cultivar replacement (+20%, lnRR = 0.18; 0.12–0.24) showing the strongest effects, whereas the efficacy of exogenous plant growth regulators was unstable (CI crossed zero). Modern hybrid cultivars improved heat tolerance; optimized nitrogen inputs buffered yield penalties by maintaining spikelets and seed-set, whereas excessive nitrogen reversed benefits. In contrast, the Yangtze River Basin reveald that ASD, once an important heat-avoidance measure, has seen its safe window narrowed over the past four decades by warming and anomalies, rendering this strategy increasingly ineffective. Consequently, while global results confirm standalone efficacy, the Yangtze case implies integrated portfolios may be needed. This study provides a robust data-driven framework for informing site- and cultivar-specific adaptation decisions under climate warming.