Effect of increasing doses of compost on chlorophyll content and branch growth in Myrteola nummularia (Poir.)

Abstract

Myrteola nummularia (Poir.), traditionally known as Myrteola, is a native Chilean species recognized for its berries with a high polyphenol content and antioxidant properties. Organic fertilization in cultivated native species promotes plant growth and physiological development. However, there is limited knowledge about the effect of organic fertilization on the physiological development and growth of M. nummularia. The objective of this study was to evaluate the effect of four compost doses (0, 5, 10, and 15 t ha⁻¹) on physiological parameters, growth, and pigments in young Myrteola plants. For this purpose, a Myrteola orchard was established in 2022 in the Ñuble Region, central-southern Chile. Physiological parameters such as the maximum quantum yield of photosystem II and stomatal conductance were measured, along with growth parameters such as plant and branch height, and leaf indices including chlorophyll, anthocyanin, and flavonoid content. The results indicated that plants responded to organic fertilization by improving physiological, growth, and leaf index parameters. The highest compost dose (15 t ha⁻¹) significantly increased chlorophyll content (66%) and branch length (32%) compared to the control, probably due to increased nitrogen availability and a more acidic pH. Therefore, organic fertilization with high compost doses (15 t ha⁻¹) enhanced Myrteola growth, promoting greater greenness and longer branches. This could improve future fruit production, making it a viable productive alternative