Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2016
Publication Date: 6/17/2016
Citation: De Oliveira, M.L., Thomson, J.G., Stover, E.W. 2016. High-efficiency propagation of mature 'Washington Navel' orange and juvenile "Carrizo" citrange using axillary shoot proliferation. HortTechnology. 26:278-286. Interpretive Summary: Traditional propagation of citrus rootstocks is by germination of nucellar seeds and citrus scion types are conventionally budded onto selected rootstocks. These methods depend on availability of fruiting rootstocks which produce nucellar seeds and sufficient scion budwood to provide numerous buds of desired size for standard propagation. When a new and highly desirable rootstock or scion is introduced, there is often limited propagation material available and efficient shoot proliferation offers an attractive alternative to increase availability. Development of routine and efficient tissue culture propagation offers the additional advantage that it would provide a source of adult-phase plant material for genetic transformation, pathology studies, and back-up of genebank collections. The objective of this research was to determine the optimal conditions to induce shoot proliferation from Carrizo and Navel, as representatives of shoot proliferation amenable and recalcitrant citrus genotypes. Washington Navel orange (Citrus sinensis L. Osb) is one of the most important fresh-fruit oranges in the USA and is showed to be recalcitrant to tissue culture proliferation. In contrast, Carrizo citrange is an important roostock of citrus, which generally confers the production of high-quality fruit of different citrus varieties and is quite amenable to tissue culture proliferation. We report the results of the effect of three media types with various concentrations of plant growth regulators to find the best condition for shoot proliferation, efficient rooting, and acclimatization of Carrizo and Washington Navel. It is demonstrated that the Driver and Kuniyki and Walnut medium (DKW) was superior for propagation of Carrizo and Navel, while Murashige and Skoog Medium (MS) was superior for rooting.
Technical Abstract: Citrus propagation by conventional means is restricted to particular season and availability of plant material. It doesn’t guarantee trueness of cultivars and mass production of certified Citrus plants throughout the year. Plant tissue culture has emerged as a powerful tool to propagation and improvement of many woody plant species including Citrus. In vitro propagation offers rapid propagation, further eliminates diseases, provides scope for the development of new cultivars through somaclonal variation and somatic hybridization. In vitro propagation efficiency in Citrus species is widely reported as dependent on culture, growth regulators, explant orientation, source of explants and genotype. We tested the effect of Wood Plant Medium (WPM), Murashige and Skoog Medium (MS) and Driver and Kuniyuki and Walnut medium (DKW) with various concentrations of benzylaminopurine (BAP), naphthalene acetic acid (NAA), and/or Kinetin were investigated on in vitro propagation of nodal segments from Carrizo and Washngiton Navel.