ADVANCING IN VITRO PROPAGATION OF TRUE-TO-TYPE LINES OF AMARANTHUS SPP. EMPLOYING SSR-BASED GENETIC EVALUATION

Amaranthaceae includes the genus Amaranthus, characterized by the enormous morphological and biological diversity that has allowed it to thrive in many diverse environments.Therefore, the development of transgenics relies largely on the ability to produce true-to-type plants using an efficient in vitro regeneration protocol.This study was conducted partly to develop a robust in vitro regeneration protocol for Amaranthus lines and partly to determine the reported protocol's usefulness by analyzing the regenerated plantlets' genetic diversity.Growth of the plants was most favorable with a sucrose concentration of 30g/L.A-20 and A-21 lines produced the highest callus induction response when 2,4-D and kinetin were used as plant growth regulators at 2.3M concentration.Callus was initiated from epicotyl explants on MS medium with 2,4 D and kinetin.Callus induction rates from different lines varied, where in A-21 and A-20 100%, in A-42 82% and A-96 58%.Callus responded well to two media combinations: one being NAA (0.5M) and Kinetin (2.3M), and the second was Zeatin (4mg/L) and IAA (0.01mg/L).Simple sequence repeats (SSR) markers were then employed to determine whether genetic diversity exists among regenerated plants of the corresponding Amaranthus line A-20, A-21, A-42, and A-96.Genetic similarity between all lines and lack of detectable variation was evident by SSR-PCR amplification of genomic DNAs with three primer sets, AHF1+AHR1, AHF2+AHR2, and AHF3+AHR3.This study describes a reliable in vitro regeneration system for true-to-type plant development.Thus, the reported methodology provides the tools for future Amaranthus genetic studies and breeding programs.