In vitro conservation of coffee-tree (Coffea arabica L.) by decreasing mineral salts in the culture medium

Abstract

The importance of the conservation of plant genetic resources is becoming higher at times when the consequences of global climate change are more acute. The coffee genus (Coffea spp) is not exempt from these risks, so it is researched some alternatives for its ex situ conservation. Specifically, the in vitro conservation methods known as 'slow growth' allow the medium-term preservation of plant material, by decreasing the growth rate and the frequency between subcultures. Studies are needed on the independent effect of variations in the concentration of essential macro and microelements in the medium-term preservation of coffee. The objective of the work was to determine the effect of the decrease of the mineral content of the culture medium in the response of in vitro coffee plants (Coffea arabica L.) preserved by a period between two and six months. The plants, previously obtained in vitro, were cultured in modified MS medium, with three treatments consisting in the reduction to 75, 50 and 25 % of their macro and microelements. The survival, the number of leaf pairs, the leaf abscission and the percentage of rooted plants were evaluated at two, four and six months. In the treatment of 50 % MS, the survival percentages varied between 85 and 100 %, and were obtained intermediate values of leaf pairs and leaf abscission, with respect to the rest of the treatments. In addition, the plants developed roots that allowed them to survive despite the lack of nutrients. With this treatment, which represents a saving of the half of the mineral components of the culture medium, it is considered feasible to preserve the coffee plants for a period up to six months.