In vitro adventitious shoot regeneration for effective maintenance of male sterile niger Guizotia abyssinica (L.f.) Cass.).

A rapid and efficient method of in vitro plant regeneration for large scale propagation of male sterile plants of niger (Guizotia abyssinica) was developed. Leaf segments from mature plants were cultured on Murashige & Skoog's basal medium (MS) supplemented with N⁶-benzyladenine (BA) and kinetin individually and in combination with low concentrations of indole-3-butyric acid (IBA); and α-Naphthaleneacetic acid (NAA). Prolific direct adventitious shoot regeneration occurred on most of the media tested. The best response in terms of frequency of shoot regeneration and the number of shoots per leaf explant was observed on medium supplemented with 2.22 μM BA. Transfer of shoot bud clusters to fresh medium with same composition promoted further multiplication of the shoot buds, while medium with reduced BA concentration (0.89 μM) facilitated shoot elongation. Shoots that were rooted on half-strength MS medium gelled with 0.2 or 0.4% agar and supplemented with 4.9μ M IBA survived with a frequency of 61.36% on transfer to ex vitrum conditions. Field evaluation of the regenerants revealed the genetic stability of the plantlets and are being used in breeding of experimental hybrids. [ABSTRACT FROM AUTHOR]