Abstract:

A study to adapt tissue culture and stem cutting techniques to vegetative propagation of Vitellaria
paradoxa (Shea tree) was conducted between March and July, 2014. The specific objectives of the
study were to: determine appropriate culture media composition for in vitro regeneration of K
paradoxa, evaluate the influence of cutting type on the rooting success of K paradoxa stem
cuttings, and assess the effects of mode of application of rooting hormones (IBA) on adventitious
root formation of V. paradoxa stem cuttings. To achieve these objectives, four media compositions
were evaluated for in vitro regeneration of V. paradoxa shoot tips; four modes of auxin (IBA)
application at three different levels of concentration were evaluated with respect to adventitious
root formation of Shea cuttings, and a third experiment was set to determine the effect(s) of cutting
types on rooting success of V. paradoxa stem cuttings. A total of 2.556 Shea stem cuttings and 360
explants were evaluated in the study. Data were then entered in Ms Excel and analyzed using Rsystem
software. Data on tissue culture regeneration were collected on survival rate, callus
development, root and shoot formation. For the stem cutting experiments, data were collected on:
number of rooted cuttings, quantity and length of developed roots including evidence of auxiliary
bud break. Frequencies were derived to determine the extent, to which explants survived, rooted,
callused or remained dormant. One way ANOVA was conducted to investigate the quality of
rooting success between the four modes of auxin application. Where treatments were found to be
significantly different, the Tukey’s Honestly Significant Difference (FISD) was used to make pair
wise comparisons. The linear relationship between rooting success and bud break was investigated
using correlation and regression analysis. The highest level of callus formation was observed in
media containing MS+BAP (27.3+1.00%) and lowest (16.7+0.58%) in the one composed of
MS+BAP+GA3. Root formation (1 1. 1=1=0.58%) was observed only for the treatment (MS+BAP +
NAA). Basal cuttings dipped for 24hr at 80ppm showed the highest rooting percentage
(69.0+3.61%) compared to the other application methods. The basal cuttings also recorded
comparatively better rooting percentage (38.1+4.00 to 69.0+3.61%) than the tip cuttings
(35.7+3.61 to 57.1+6.66%). Results also revealed that bud break was generally lower in basal
cuttings and that bud break and root number were positively correlated (r=0.577). It was therefore
recommended that further experimentation needs to be conducted on tissue culture using more
media compositions and explants so as to enhance survival rate and generate V. paradoxa
plantlets. Also, a thorough study should be carried out on the potential for foliar application of
IBA, such that if adapted well, it can be incorporated for mass production of V. paradoxa subsp.
nilotica. For now the 24hr long soak method at 80ppm is recommended for large scale propagation
of V. paradoxa using stem cuttings.