Effect of explant and picloram on embryogenic callus formation in 'Blanco de Guinea' yam/Efecto del explante y el picloram en la formacion de callos embriogenicos en name , var. 'Blanco de Guinea'

The shortage of planting material of physiological and sanitary quality continues to limit the large-scale production of yam cultivation since the tubers, which constitute the useful part of the plant for food, also have to be used as planting plant material. The work was developed with the objective of evaluating the explant type effect and the concentration of picloram in the formation of embryogenic callus in Dioscorea cayenensis subsp rotundata cultivar Blanco de Guinea. Nodal segments, immature leaf and root segments from in vitro plants were taken as explants. The culture medium for callus formation contained the DM salts and different concentrations of Picloram (0; 0.5; 1.0; 1.5; 2.0 mg [L.sup.-1]). The callus formation percentage was determined for each type of explant, the color and consistency of the callus. It was achieved with the use of 2.0 mg [L.sup.-1] of Picloram, 80% of nodal segments with embryogenic callus formation, yellowish-brown in color, compact and friable.