Positive effects of the application of biostimulants in mango and avocado in yield and pre and postharvest quality parameters

The fruit agribusiness sector is one of the most dynamic sectors in Colombia, and it has recently seen a high increase in planted areas, production volume, and participation in exportation [1] (*). Within this sector, the production of avocados and mangos is particularly important. The avocado (Persea americana Mill.) is a perennial plant that belongs to the Lauraceae family, within which the cv. Hass stands out worldwide due to its good flavor, nutritional value, long postharvest life, and other outstanding properties [2,3]. Meanwhile, the mango (Mangifera indica L.), is among the most important tropical fruits in the world [4], playing an important role in the economic development of tropical countries [5]. Traditionally, avocado and mango production systems worldwide have been managed under conventional strategies, which include the use of products of chemical origin (fungicides, fertilizers, biostimulants, etc.), with a view to rational use and ensuring the safety of the fruit [6,7,8]. Nonetheless, other types of systems can be implemented, such as clean and/or organic production. The organic production of avocado is still incipient (<10% of the area planted worldwide), but a market niche is there to be explored, and its implementation offers environmental advantages [6,7]. In view of this, the implementation and validation of management practices aimed at organic production systems is an area of technological demand among producers worldwide. Currently, the main objective of the production of fruit trees around the world is to increase yields (t ha?1) without affecting quality parameters such as flavor, color, size, shape, smell, and postharvest duration. Despite the large volume of mango production, low productivity per unit area remains a problem, which greatly affects its exportation [9]. In addition, avocado production systems present productive and technological limitations, with lower than potential yields, especially under tropical conditions such as in Colombia [10]. One avocado and mango crop management tool geared towards improving quality is the application of energy sources to increase fruit set and quality [11]. This strategy can be carried out through the application of biostimulants. These compounds are an important and sustainable strategy to increase crop yield and quality. Effects of the biostimulantsBiostimulants can improve plant growth, nutrient use efficiency, and stress tolerance, all of which can enhance flowering, plant growth, fruit set, crop productivity, and nutrient use efficiency [12,13,14]. Recent reports have indicated that biostimulants can improve crop yields and also significantly reduce the need for fertilizers [12]. Biostimulants are a promising and environmentally friendly innovative new tool for sustainable agriculture [12]. They have the potential to reduce our reliance on chemical fertilizers and pesticides [12]. The possible function of biostimulants in plants may have two mechanisms (i) they can directly interact with plant signaling cascades and (ii) stimulate endophyte microorganisms to produce molecules that are beneficial to the plant [12,13]. Rouphael and Colla [13] reported that plant biostimulants comprise substances of organic and inorganic origin, including microorganisms, whose objective is to improve nutrient use efficiency, tolerance to abiotic stress, and crop quality. There is also evidence that biostimulants trigger physiological and molecular processes, increase crop yield, and improve the physicochemical characteristics of the fruits [14]. Types of biostimulantsThere are different types of biostimulants; mainly, they are composed of humic substances, complex organic materials, stimulating chemical elements, inorganic salts, algae and plant extracts, protein hydrolysates, amino acids, chitin and chitosan derivatives, antiperspirants, and other compounds [13]. Recently, it was found that the use of biostimulants in apple trees improves plant growth [15]. Biostimulants with amino acids have been found to increase the production of ?Edward? mangos [16], and biostimulants with bioregulators have also increased yield in blueberries [17]. In apricots, carboxylic acids increased production by up to 58% after the second year [18]. It has been reported by many researchers that the application of biostimulants improves the quality of fruits and vegetables [19]. Tarantino et al. [18] found a significantly positive effect on the fruit antioxidant capacity of the apricot cultivar ?Orange rubis? of all biostimulant treatments with respect to the control, although no effects on titratable acidity and total soluble solids or maturity ratio were found. Important advances have been made in the study of the physiological and biochemical mechanisms of biostimulants on plants [13]. Objective of the workNevertheless, few studies have evaluated the effect of molecules associated with the application of biostimulants in the field and their effect on the yield and pre- and postharvest quality parameters of avocado and mango fruit, especially under organic production systems. Therefore, the objective of this work was to determine the effect of the preharvest application of a biostimulant on the yield and postharvest quality of Hass avocado (traditional and organic) and mango fruit crops destined for both domestic and export markets. The avocado was cultivated under both traditional and organic production systems. This was to confirm whether the biostimulant improves fruit production without negatively affecting postharvest performance since it has been reported that pre-harvest factors and practices can impact the post-harvest quality of the fruits [20,21]. The studyThe study was carried out in production systems for cv. Hass avocado (traditional and organic) and cv. Keitt mango (traditional). In each system, two treatments were evaluated: conventional and conventional + biostimulant. Under field conditions, yield and quality variables such as weight, number of fruits, visual appearance, and size were determined. In postharvest, the fruits obtained from preharvest treatments were subjected to two storage conditions (6 and 20 ?C) during the ripening process. Postharvest quality variables such as respiration, ethylene rates, weight loss, color index, firmness, total soluble solids, and titratable acidity were evaluated. ResultsThe results indicated that the use of biostimulants caused a significant increase (p ? 0.05) in the yield, number of fruits, and preharvest quality parameters of size and weight, without negatively affecting the postharvest quality of the fruits.The biostimulant increases the total weight of fruits in organic and conventional avocado by ~55 and 25%, respectively, while in mango, this figure increased by ~23%. Hence, biostimulants can be utilized to increase the productivity of fruit trees. (*) References in the original paper, below. SourcesBiostimulants Improve Yield and Quality in Preharvest without Impinging on the Postharvest Quality of Hass Avocado and Mango Fruit: Evaluation under Organic and Traditional SystemsMariana Lucia Rojas-Rodr?guez,Joaqu?n Guillermo Ram?rez-Gil,Luis Felipe Gonz?lez-Concha and Helber Enrique Balaguera-L?pezAgronomy 2023, 13(7), 1917https://doi.org/10.3390/agronomy13071917This article belongs to the Special Issue The Studies on Plant Biostimulants to Improve Yields and Sustainability in Agriculture Picture by Reyes Guti?rrez, avocado grower and exporter ?