Development of a Comprehensive Quality Evaluation System for Foxtail Millet from Different Ecological Regions.

Foxtail millet (Setaria italica L.) is a critical grain with high nutritional value and the potential for increased production in arid and semiarid regions. The foxtail millet value chain can be upgraded only by ensuring its comprehensive quality. Thus, samples were collected from different production areas in Shanxi province, China, and compared in terms of quality traits. We established a quality evaluation system utilizing multivariate statistical analysis. The results showed that the appearance, nutritional content, and culinary value of foxtail millet produced in different ecological regions varied substantially. Different values of amino acids (DVAACs), alkali digestion values (ADVs), and total flavone content (TFC) had the highest coefficients of variation (CVs) of 50.30%, 39.75%, and 35.39%, respectively. Based on this, a comprehensive quality evaluation system for foxtail millet was established, and the quality of foxtail millet produced in the five production areas was ranked in order from highest to lowest: Dingxiang > Zezhou > Qinxian > Xingxian > Yuci. In conclusion, the ecological conditions of Xinding Basin are favorable for ensuring the comprehensive quality of foxtail millet. .

Transcriptome Analysis Reveals Brassinolide Signaling Pathway Control of Foxtail Millet Seedling Starch and Sucrose Metabolism under Freezing Stress, with Implications for Growth and Development.

Low-temperature stress limits the growth and development of foxtail millet. Freezing stress caused by sudden temperature drops, such as late-spring coldness, often occurs in the seedling stage of foxtail millet. However, the ability and coping strategies of foxtail millet to cope with such stress are not clear. In the present study, we analyzed the self-regulatory mechanisms of freezing stress in foxtail millet. We conducted a physiological study on foxtail millet leaves at -4 °C for seven different durations (0, 2, 4, 6, 8, 10, and 12 h). Longer freezing time increased cell-membrane damage, relative conductance, and malondialdehyde content. This led to osmotic stress in the leaves, which triggered an increase in free proline, soluble sugar, and soluble protein contents. The increases in these substances helped to reduce the damage caused by stress. The activities of superoxide dismutase, peroxidase, and catalase increased reactive oxygen species (ROS) content. The optimal time point for the response to freezing stress was 8 h after exposure. The transcriptome analysis of samples held for 8 h at -4 °C revealed 6862 differentially expressed genes (DEGs), among which the majority are implicated in various pathways, including the starch and sucrose metabolic pathways, antioxidant enzyme pathways, brassinolide (BR) signaling pathway, and transcription factors, according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. We investigated possible crosstalk between BR signals and other pathways and found that BR signaling molecules were induced in response to freezing stress. The beta-amylase (BAM) starch hydrolase signal was enhanced by the BR signal, resulting in the accelerated degradation of starch and the formation of sugars, which served as emerging ROS scavengers and osmoregulators to resist freezing stress. In conclusion, crosstalk between BR signal transduction, and both starch and sucrose metabolism under freezing stress provides a new perspective for improving freezing resistance in foxtail millet.

The relationship between ecological factors and commercial quality of high-quality foxtail millet "Jingu 21".

The commercial quality of foxtail millet grain (Setaria italica L.) includes appearance quality, functional quality, and cooking and eating quality, which directly determine whether consumers will purchase the product. We studied the relationship between ecological factors and commercial quality attributes of foxtail millet "Jingu 21" from twelve production areas. The results showed that altitude, latitude, and diurnal temperature range were negatively correlated with b*, total flavones content (TFC), setback (SB), consistence (CS) and pasting temperature (PTM), but positively correlated with L/B and breakdown (BD). In contrast, average temperature, average precipitation, average humidity, available nitrogen, phosphorus, and potassium had positive effects on 1,000-grain weight (KGW), b*, TFC, CS, and PTM and had a negative impact on L/B and BD. Climate factors had a greater effect on the commercial quality of foxtail millet than soil factors, and the influence of climatic factors was particularly obvious in the early and middle growth periods. The multivariate equation between ecological factors and the comprehensive score of foxtail millet commercial quality is Y = 1,159.745-4.496X1 (altitude) + 19.529X5 (≥10℃ effective accumulated temperature) - 166.327X10 (organic matters). In conclusion, high temperature and precipitation are conducive to high quality appearance and the accumulation of functional substances, while a high diurnal temperature range and high soil nutrients are conducive to the formation of cooking and eating quality. The impact of ecological factors on foxtail millet quality is complicated and it is essential to select a cultivation site that is matched to the intended use of the foxtail millet being produced.