African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 11997

Full Length Research Paper

Drought tolerant tropical maize (Zea mays L.) developed through genetic transformation with isopentenyltransferase gene

Leta Tulu Bedada
  • Leta Tulu Bedada
  • Ethiopian Institute of Agricultural Research, P. O. Box 2003, Addis Ababa, Ethiopia.
  • Google Scholar
Miccah Songelael Seth
  • Miccah Songelael Seth
  • Mikocheni Agricultural Research Institute, Mikocheni B Light Industrial Area, Plot No. 24B, Along Coca Cola Road, P. O. Box 6226, Dar Es Salaam, Tanzania.
  • Google Scholar
Steven Maina Runo
  • Steven Maina Runo
  • Plant Transformation Laboratory, Department of Biochemistry and Biotechnology, Kenyatta University, P. O. Box 43844, GPO 00100, Nairobi, Kenya.
  • Google Scholar
Wondyifraw Teffera
  • Wondyifraw Teffera
  • Ethiopian Institute of Agricultural Research, P. O. Box 2003, Addis Ababa, Ethiopia.
  • Google Scholar
Charless Mugoya
  • Charless Mugoya
  • Association for Strengthening Agricultural Research in East and Central Africa (ASARECA), P. O. Box 765, Entebbe, Uganda.
  • Google Scholar
Clet Wandui Masiga
  • Clet Wandui Masiga
  • Association for Strengthening Agricultural Research in East and Central Africa (ASARECA), P. O. Box 765, Entebbe, Uganda.
  • Google Scholar
Richard Okoth Oduor
  • Richard Okoth Oduor
  • Plant Transformation Laboratory, Department of Biochemistry and Biotechnology, Kenyatta University, P. O. Box 43844, GPO 00100, Nairobi, Kenya.
  • Google Scholar
Eduardo Blumewald
  • Eduardo Blumewald
  • 5Department of Plant Sciences, University of California, Davis, CA, USA.
  • Google Scholar
Francis Wachira
  • Francis Wachira
  • Association for Strengthening Agricultural Research in East and Central Africa (ASARECA), P. O. Box 765, Entebbe, Uganda.
  • Google Scholar


  •  Received: 18 January 2016
  •  Accepted: 21 July 2016
  •  Published: 26 October 2016

Abstract

Maize is a staple food crop for millions of Africans. Despite this fact, African farmers have been harvesting average grain yield of not more than 2 t/ha while there is a potential of producing more than 10 t/ha. Drought is one of the major abiotic constraints contributing to this low productivity. Drought diminishes crop productivity mainly by causing premature leaf senescence. The ipt gene codes for isopentenyltransferase (IPT) enzyme which catalyzes the rate limiting step in the biosynthesis of cytokinin and has been shown to enhance tolerance to drought in transgenic crops by delaying drought-induced leaf senescence. This created interest to investigate if ipt gene can be useful in enhancing drought tolerance in locally adapted African tropical maize genotypes. The tropical maize inbred line CML216 was transformed with ipt gene using Agrobacterium-mediated transformation method. Five transgenic lines which were proved to be stably transformed through Southern blot analysis with copy number of 2 to 4 per event were developed. In drought assay carried out in the glass house, transgenic lines expressing the ipt gene showed tolerance to drought as revealed by delayed leaf senescence compared to the wild type plants. Transgenic plants maintained higher relative water content and total chlorophyll during the drought period and produced significantly higher mean grain yield of 44.3 g/plant while the wild type plants produced mean grain yield of 1.43 g/plant. It is proposed that the transgenic lines developed in this study can be further tested for tolerance to drought under contained field trials. Furthermore, transgenic lines developed can be used in breeding programs to improve drought tolerance in other commercial tropical maize genotypes through conventional breeding.

Key words: Cytokinin, delayed leaf senescence, drought inducible, CML216, ipt gene.