Objective Based on agronomic traits and polysaccharide content of the plants, optimal times to harvest two newly certified Polygonatum cyrtonema Hua were determined using PCA and CRITIC analyses.

Methods Agronomic characteristics of two newly certified Polygonatum cyrtonema Hua, the round-leaf Minyuanjing No. 1 (Min Renyao 2024002) and the long-leaf Minchangjing No. 1 (Min Renyao 2024003), were continuously observed from May through October with polysaccharide content of the plants monitored. One-way ANOVA, PCA, cluster, and CRITIC analyses were performed for correlation between the two sets of the collected data to determine the optimal time for harvest.

Results As the plants grew, the polysaccharide contents in Minyuanjing No. 1 and Minchangjing No. 1 rose gradually to peak in October at 14.23±1.62% and 15.80±1.55%, respectively. In addition, the average stem diameter of both Minyuanjing No. 1 and Minchangjing No. 1 exceeded 8 mm. The measurements correlated significantly with the stem diameter, fresh leaf weight, and weight of fresh root of the plants (P＜0.01), while the three top principal components explained 60.50% of the variance on rhizome and roots. A cluster analysis classified the two cultivars at 5 harvest times into three groups. And since Minyuanjing No. 1 in September and Minchangjing No. 1 in October received the highest CRITIC comprehensive scores (S), optimal months for harvest of the two cultivars were selected. The regression equation obtained for S and agronomic traits was S=0.204+0.164×total plant height+0.230×fresh stem weight+0.163×fresh rhizome weight with R²=0.715 and statistical significance at P＜0.01.

Conclusion September was determined to be the time to harvest Minyuanjing No. 1, and October, Minchangjing No. 1. Largely. The accumulation of polysaccharides can be predicted by monitoring stem diameter (＞8 mm), and it is recommended to focus on cultivation management. This study provides a scientific basis for the accurate harvesting of P. cyrtonema.