EFFICACY OF A LOW-COST AGROCHEMICAL THIDIAZURON IN INDUCTION OF REGENERATION FROM COTYLEDONS OF MELIA VOLKENSII GURKE

Abstract

Mass propagation via tissue culture technology could rescue threatened indigenous medicinal, pesticidal andtimber plants. However, its application remains underutilized locally due to high costs of tissue cultureconsumables. Local efforts towards reduction of costs have centered on use of cheaper carbon sources such astable sugar, substitution of Murashige and Skoog and Gamborg’s salts with mixtures of fertilizers andsubstitution of conventional gelling agents agar, gelrite and phytogel with cassava starch. However, a gapexists on the identification of cheaper substitutes of conventional plant growth promoters yet these,particularly cytokinins, are important cost drivers in tissue culture. Half a gram of plant-cell-culture-testedThidiazuron (TDZ) from Sigma-Aldrich costs 2,145 Euros (Ksh 235,500) while 1 g of Zeatin costs 4,220 Euros(Ksh 463,514). This study sought to determine whether a low-cost agrochemical TDZ that costed only 0.229USD (Ksh 19.84) per gram and was recently reported by the present authors to support high frequencyregeneration in mature zygotic embryos of M. volkensii, could elicit similar response in other explants.Cotyledons of mature seeds from wild trees in Kitui were cultured in ½ MS medium containing eight TDZconcentrations from 0 to 4 mg/l. High frequency (80 to 100 %) direct regeneration of shoots was observedwithin 14 days. TDZ treatments had a significant effect (Ftestp < 0.001) on the regeneration response in relationto the non-morphogenic controls. Shoots were elongated on ½ MS + 0.1 mg/l 6-Benzylaminopurine incombination with either 0.01 mg/l 1AA or 10% coconut water and rooted in ½ MS + 0.1 mg/l Indole-3-butyricacid. Low-cost agrochemical TDZ could substitute the exorbitant plant-cell-culture-tested Thidiazuron in tissueculture of M. volkensii. We recommend testing of this agrochemical on more explants and species.