Objective  Effects of foliar spraying different calcium solutions on the agronomic traits of chili pepper were studied for crop yield and quality improvements.

  Method  Four foliar spraying treatments using water (CK) or solutions of calcium chloride (G1), calcium sugar alcohol (G2), and small molecular peptide calcium (G3) were performed on chili pepper plants. Major agronomic characteristics, calcium content, yield, and quality of the plants were determined.

  Result  The various calcium sprays hastened the pepper ripening and increased the fruit calcium content. Compared with CK, the G3-treated peppers increased significantly by 22.02% on fresh weight and by 38.77% at 536.9 g on yield per plant. Meanwhile, the content and the accumulation of calcium in the fruit reached 2.78 g·kg⁻¹ and 96.86 g per plant, representing significant increases over CK by 46.32% and 78.25%, respectively. In the aboveground pepper plant, the fruits had a significantly increased share of calcium by 58.58% and Vitamin C (0.6378 mg·g⁻¹) by 17.29% over those of CK. The G3-treated peppers also had higher yield per plant, fruit weight, and Vitamin C by 18.0%, 33.8%, and 18.3%, respectively, than the G1-treated ones, and significantly higher fresh shoot weight, mature fruit count, and yield per plant than the G2 counterparts. The sprays also resulted in more accumulations of nitrogen, potassium, and calcium in the aboveground parts of the plants.

  Conclusion   The small molecule peptide calcium used in the foliar spraying was more efficient than the other forms in transferring calcium from the leaves to the fruits of a chili pepper plant. It was recommended for promoting the plant growth as well as increasing the yield and nutritional quality of chili peppers.