Regeneration of Somaclonal Variants of Tomato (Solanum lycopersicum L.) for Resistance to Fusarium Wilt

Abstract

Somaclonal variants arising from clonally propagated plants via plant tissue culture could possess resistance to some diseases. Cotyledon, leaf, and hypocotyl explants from a local variety of Fusarium wilt-susceptible tomato (Solanum lycopersicum L. cv. Beske) were cultured on callus induction media (CIM) with kinetin, 6-benzylaminopurine (BAP), and naphthaleneacetic acid (NAA) at various concentrations. Calli were transferred to shoot regeneration media containing kinetin and BAP in combination with giberellic acid at 0.5 mg/l. Regenerated plantlets and nursery-raised seedlings (control) were inoculated with Fusarium wilt pathogen. Callus induction was between 85.71% and 100.00% on all CIM except hormone-free medium. Disease incidence (70%) and severity score of 3.43 using the area under disease progress curve and taken at 14 days after inoculation were lowest in variants regenerated from leaf explants. We concluded that somaclonal variants of tomato with moderate resistance to Fusarium wilt could be generated in vitro from a susceptible variety through manipulation of growth media.

KEYWORDS:

• callus induction
• disease resistance
• growth media
• shoot proliferation with GA₃
• tissue culture

ABBREVIATIONS:

• (AUDPC) area under disease progress curve
• (BAP) 6-benzylaminopurine
• (CIM) callus induction medium
• (IBA) indole-3-butyric acid
• (MS) Murashige and Skoog
• (NAA) naphthaleneacetic acid
• (PDA) potato dextrose agar
• (RRM) root regeneration medium
• (SRM) shoot regeneration medium

Additional information

Funding

The authors acknowledge the funds provided by the Agricultural Research Council of Nigeria under the Competitive Agricultural Research Grant Scheme, CARGS. The work was also partly supported by the United Kingdom’s Department for International Development (UK’s DfID) under DElPHE-5 Grant Scheme. We appreciate the technical assistance provided by the staff of Tissue Culture Laboratory, National Centre for Genetic Resource and Biotechnology, Ibadan, Nigeria.