Physiological potential of piquin pepper seeds in response to pregermination treatments

Abstract

Wild piquin pepper fruits are consumed and traded because of their flavor, nutritional and pharmaceutical properties. The heterogeneous germination of its seeds has caused pregermination treatments to be unstandardized. Because of that, our goal was to evaluate pregermination treatments of piquin pepper seeds from a wild plant from the municipality of Victoria, Tamaulipas, Mexico, consisting of immersion for different periods (2, 24, 48 h) in solutions with variable concentrations of the growth regulators naphthalene acetic acid (NAA; 0.1, 1.0, 2.5 mM), salicylic acid (SA; 1.0, 5.0, 10 mM), gibberellic acid (GA3, 1.0, 5.0, 10 mM), indole-3-butyric acid (IBA; 1.0, 2.0, 3.0 mM), the commercial product Biozyme (Bioz) containing minerals and growth regulators (Bioz; 0.5, 1, 2%), and sulfuric acid (H2SO4; 2, 5, 10%) in a completely randomized design, using distilled water as the control. For each treatment, we measured the imbibition ratio, germination percentage, time to obtain 50% germination (T50), and coefficient of variation of germination time (CVt). Our results showed that the imbibition was similar in the control and the treatments, but it differed between treatments. The highest imbibition recorded in 48 h was 87%. The highest germination percentage (79.2%) was achieved with 2 h immersion in 2% Bioz, followed by 1 mM NAA (62%) and 5 mM SA (56%). T50 and CVt were 10-26 d and 0-39%, respectively. According to our results, we concluded that the pregermination treatments we assayed improved the physiological potential for the germination of piquin pepper seeds.

Aqueous extract of coconut shell biochar as a pre-germination treatment increases seed germination and early seedling growth in chiltepín pepper (Capsicum annuum var. glabriusculum)

“…The imbibition rates determined here were similar to those of Cano-Vázquez et al (2015) and Cano-González et al (2021). Imbibition percentages > 50% after the first 4 h of seed immersion in the CSBA solution (highest with CSBA0.25, CSBA0.50, and CSBA1.00; Figure 3) reflect the absence of morphological germination problems due to the presence of a too-thick testa, since high testa lignification can prevent or reduce imbibition and gaseous exchange between the embryo and the environment (Bissoli et al, 2022).…”

“…Each treatment comprised five replicates of fifty seeds per replicate. The imbibition was expressed as the percentage difference seed's initial dry weight (DW) and the fresh weight (FW) of the seed after application of the treatment over time (Cano-González et al, 2021):…”

“…Similarly, the percentages of normal (%NS) and abnormal seedlings (%AS) were quantified. Germination test was conducted for 35-days, according to previous studies since chiltepín seed can take up to 28-days to germinate (Quintero et al, 2018;Cano-González et al, 2021). The percentage of abnormal seedlings included those where the roots were stunted, missing, broken, or split at the tip, as well as those with short, stout, slit, shrunken, twisted or rotten shoots, and deformed, damaged or missing leaves (ISTA, 2020).…”

“…Its fruit has great relevance in Mexico due to its high market demand (Cano-Vázquez et al, 2015) because of its rich, aromatic profile (Mares-Quiñones and Valiente-Banuet, 2019), high antioxidant capacity, and high phenol, flavonoid, capsaicinoid, capsinoid, carotenoid, tocopherol, tocotrienol, and ascorbic acid content (Hayano-Kanashiro et al, 2016;Quintero et al, 2018;Vazquez-Flores et al, 2020). This C3-type plant is characterized by its shrub-like wild growth, reaching heights of 55-150 cm; compact, berry-like, spherical or ovoid fruit (0.87-1.68 cm in length, 0.45-0.81 cm in diameter, 0.20-0.55 g in weight, and 0.45-0.82 mL by volume); 2.5-3.0-mm hard-coated seed, and maturity time of 6-10 months (Hayano-Kanashiro et al, 2016;Mares-Quiñones and Valiente-Banuet, 2019;Beltrán-Burboa et al, 2020;Cano-González et al, 2021). Due to the scarcity of information regarding an adequate production system, fruit collection usually involves cutting or removing whole branches, leading to a loss of genetic diversity (Mares-Quiñones and Valiente-Banuet, 2019).…”

“…Studies by Sandoval-Rangel et al (2018) and Mares-Quiñones and Valiente-Banuet (2019) have suggested that the seed embryo may require at least two months of rest after harvesting to reach maturity, whereas the seed can germinate 7-28 days after sowing. In this context, several strategies have been developed to promote chiltepín pepper seed germination, including the exogenous application of gibberellic acid (GA3), indole-acetic acid, indole-3-butyric acid (IBA), naphthalene acetic acid (NAA), salicylic acid (SA), hydrochloric acid, nitric acid, sulfuric acid (H2SO4), hydrogen peroxide, kinetin, and potassium nitrate in various doses and at different priming times, achieving good results (Cano-Vázquez et al, 2015;Quintero et al, 2018;Sandoval-Rangel et al, 2018;Alcalá-Rico et al, 2019;Beltrán-Burboa et al, 2020;Cano-González et al, 2021;Junaidy and Shahruddin, 2022). Because there is no pre-germination protocol for this seed type (Cano-González et al, 2021), and given the requirement for adequate conditions, it has become necessary to expand the strategies used to improve chiltepín pepper' physiological germination potential, such as applying biochar.…”