Animal and plant-derived protein hydrolysates positively affect yield traits but produce contrasting response on chemicals of organic rosemary (Salvia rosmarinus Spenn.) grown under rainfed conditions

Abstract

Rosemary (Salvia rosmarinus Spenn.) is a perennial crop which is well known for its antibacterial, anti-inflammatory, and antioxidant properties. It is widely documented that the biosynthesis of bioactive compounds in this plant is strongly influenced by endogenous and exogenous factors. To enhance yield production and reduce the effects of these factors on open field crops, certain agronomic practices can be optimized through the use of innovative products. The foliar application of protein hydrolysates is recognized as a good practice to achieve this. A two-year study was carried out to investigate the impacts of two different protein hydrolysates (animal-based and plant based) on the yield traits and chemical parameters of rosemary. A randomized complete block design was used with three replicates. The results highlighted that both biostimulants produced a substantial increase in fresh biomass between 1.4 and 3.9 Mg ha-1, and in dry biomass between 0.5 and 1.3 Mg ha-1, in comparison with the control plants. It was found that the lowest dose of plant-based protein hydrolysates significantly increased essential oil yields, producing yields of over twenty kilograms per hectare. It is worth noting that the application of both protein hydrolysates did not modify the aromatic profile of the essential oil. In addition to this, contrasting responses were observed when considering the effect of these biostimulants on the antioxidant activity, phenolic content, and rosmarinic acid. The results of this study demonstrate that protein hydrolysates improve the yield of rosemary plants cultivated under organic agriculture conditions.