Multi-environment evaluation of proso millet identifies stable genotypes and reveals the roles of amylose content and particle size distribution in processing quality.

Proso millet quality is jointly determined by genotype and genotype-by-environment interaction (GEI). Herein, 18 genotypes grown across 8 ecoregions were evaluated for grain color, nutritional composition, yield, and processing-related traits. Multi-model analyses demonstrated that genotype was the major source of variation, whereas significant GEI was detected for all measured traits. JM18 was identified as a stable genotype for grain color and yield, whereas JM02 (4.25), JM04 (4.27), and JM06 (4.31) were selected as promising for genotypes based on combined trait performance. The high starch group (HSG) exhibited higher amylose content (14.42%), smaller particle size (34.41 μm), superior pasting behavior, and better cooking performance than those by the low starch group (LSG). Notably, the low-starch environment attenuated particle aggregation and textural hardness in HSG. Collectively, genotype predominantly regulates processing quality through amylose content, whereas environmental effects are comparatively weaker and are mainly mediated by flour particle size distribution and microstructure.