Comprehensive agrobiological and biochemical study of sweet pepper (Capsicum annuum L.) varieties

Abstract

Background: Sweet pepper (Capsicum annuum L.) fruits are characterized by a high content of vitamin C, carotenoids, and other biologically active compounds that contribute to their nutritional value. Under protected cultivation conditions, this crop ensures stable production of high-quality fruits regardless of seasonal variability. The identification and selection of cultivars capable of accumulating elevated levels of these compounds are of considerable interest for the agricultural sector and the development of functional food products.

Objective: The aim of this study is to conduct a comparative agronomic and biochemical evaluation of Armenian sweet pepper varieties grown under protected cultivation conditions.

Methods: Тhe study was conducted from 2022 to 2024 under greenhouse conditions at the Scientific Centre of Vegetable and Industrial Crops. Nine promising sweet pepper (Capsicum annuum L.) varieties- Sate, Manana, Yana, Loshtak, Jermatnayin Hska, Narinj, Araqsi-23, Teghakan-7, and Nizak - were evaluated. Phenological observations, morphological characterization, yield assessment, and fruit quality evaluation were performed throughout the growing season. Biochemical parameters of the fruits were determined using spectrophotometric methods, while dry matter content was measured with a refractometer. Statistical analysis included ANOVA (p ≤ 0.05), LSD test, and Pearson correlation.

Results: The varieties showed significant differences in developmental timing, fruit shape and color, yield, and nutrient content. The period from emergence to flowering ranged from 80 to 97 days; technical maturity was reached in 107–121 days, and biological maturity in 135–145 days. Fruit morphology varied (cuboid, prismatic, conical), and color transitioned from green at the unripe stage to red, orange, or yellow at full maturity. Yields ranged from 13.4 to 22.6 kg/m², depending on the variety.

The highest levels of vitamin C and total sugars at both ripening stages were recorded in Araqsi-23, Jermatnayin Hska, and Manana. These varieties also demonstrated the highest sweetness index due to their elevated sugar and low acid content. The varieties Sate, Yana, and Narinj exhibited balanced biochemical profiles, making them suitable for both fresh consumption and processing. Loshtak, Teghakan-7, and Nizak had lower values, indicating their suitability for industrial processing. Chlorophyll content in unripe fruits was higher in dark-green-fruited varieties. The highest carotenoid levels were found in red-fruited varieties (Yana, Loshtak, Jermatnayin Hska, Nizak, and Teghakan-7), ranging from 1112.0 to 1995.2 μg/100 g fresh weight. Orange-fruited varieties (Narinj, Araqsi-23) and yellow-fruited ones (Sate, Manana) showed moderate and relatively lower carotenoid content. Importantly, all varieties contained vitamin C levels that exceed the recommended daily intake, emphasizing their high nutritional value.

Novelty: A comprehensive agrobiological and biochemical evaluation of nine Armenian sweet pepper varieties grown under protected cultivation was conducted for the first time. A correlation between morphological and biochemical traits of the fruits was established, which has not been previously reported in the scientific literature. Varieties with high levels of bioactive compounds were identified, highlighting their value for functional food production and breeding within the framework of sustainable agriculture. 

Conclusion: The sweet pepper varieties differed in maturation period, fruit morphology, and levels of bioactive compounds. Several varieties combined high yield potential with notable nutritional value, confirming their suitability for protected cultivation and functional food production. The findings emphasize the importance of an integrated breeding approach focused on enhancing agronomic and nutraceutical traits.

Keywords: sweet pepper, Armenian varieties, greenhouse, phenological characteristics, fruit morphology, ascorbic acid, total carotenoids, total sugars, dry matter chlorophylls, antioxidant properties, yield