In vitro regeneration of cocona (Solanum sessiliflorum, Solanaceae) cultivars for commercial production

Abstract

ABSTRACT. Cocona (Solanum sessiliflorum Dunal) is a solanaceous shrub native to the Amazon region that produces an edible fruit. This species has numerous advantages, particularly a high nutritional value and productivity. However, due to irregular germination and rapid loss of seed viability, there are few plantations for production on a large scale. Development of alternative propagation strategies is essential for the production of homogeneous seedlings of genotypes with superior agronomic performance. We developed techniques for in vitro regeneration of the cocona varieties Santa Luzia and Thaís for large-scale production of healthy plantlets. Twenty days after seeding, seedling segments germinated in vitro were used as explant sources. Three successive experiments were performed: one to test the effect of the explant source and combinations of two growth regulators, auxin (indole acetic acid, IAA) and kinetin (KIN), on the morphogenetic response; another to investigate the effect of the combination of growth regulators on the morphogenetic response of hypocotyl segments, and another to evaluate how sucrose concentration affects the development of adventitious shoots. The best shoot induction was obtained using hypocotyl segments and stem apices, while rhizogenesis was greatest in leaves with a petiole. The number of adventitious shoots per explant on hypocotyl segments increased with 10 and 20 mg/L KIN, combined with 0.02 mg/L IAA in the variety Santa Luzia. Sucrose combined with these growth regulator levels increased the average number of calli; these were optimally produced when 45 g/L sucrose and 0.01 mg/L IAA + 20 mg/L KIN were applied. Only sucrose concentration influenced shoot proliferation in the two S. sessiliflorum varieties, with a maximum at 17.5 g/L.

Micropropagation of <i>Solanum quitoense</i> var. <i>quitoense</i> by apical bud, petiole and hypocotyl culture

“…2009). The size of these adventitious shoots from hypocotyl segments were small (<5 mm) (Schuelter et al 2009), similar to our results (size mean=3.9 mm) with S. quitoense hypocotyls.…”

“…However, these results were not significantly different from the other BAP concentrations tested (Table 3). Combinations of auxins and cytokinins have been previously used for the successful hypocotyl regeneration of other Solanum species from the Lasiocarpa section (Schuelter et al 2009;Te-chato 1988). For S. sessiliflorum, high rates of shoot induction have been reported using hypocotyls in media supplemented with 0.01 mg l −1 indole acetic acid (IAA) and 20.00 mg l −1 kinetin (KIN) (Schuelter et al.…”

“…Cytokinins play an important role in the natural physiology of plant cells, but identifying the optimal concentration is key for their use in in vitro culture, as an excess of these growth regulators may cause a phytotoxic effect (Schuelter et al 2009). Our results show a favorable response to BAP concentrations of up to 6.00 mg l −1 , which agrees with previous reports that suggest that a concentration of 10.00 mg l −1 (in combination with NAA 0.01 mg l −1 ) has an inhibitory effect in shoot formation from hypocotyls in Solanum quitoense (Te-chato 1988).…”

“…In vitro micropropagation studies have been conducted for some members of the Lasiocarpa section. Methodologies for shoot induction from hypocotyl segments, stem apices and young leaf explants have been successfully established for Solanum sessiliflorum (Schuelter et al 2009), Solanum surattense (Gupta and Handra 1982) and Solanum melongena (Mukherjee et al 1991). Shoot regeneration studies have also been reported from foliar explants in Solanum candidum, S. sessiliflorum and S. quitoense, with the latter showing a lower regeneration frequency (Hendrix et al 1987;Medina-Rivas et al 2008).…”

Hydric-stress Tolerance in Cocona (Solanum sessiliflorum Dunal)

“…This section holds 13 cultivate species distributed from northern Andes region to Amazon. Cocona is distributed in the Amazon region, which includes Peru, Ecuador, Brazil, Colombia and Venezuela [1,2]. This region presents heavy high rainfall (>2500mm).…”