Abstract
Rose (Rosa hybrida Vill.) production is limited by a variety of factors such as poor mineral nutrition, high salinity, pests and diseases. Crown gall disease caused by Agrobacterium tumefaciens causes a significant damage to roses in Kenya. The study was carried out in Winchester farm (Nairobi) and Bahati farm (Nakuru) to determine the effects of a mixture of amino oligosaccharins and Alternaria fine proteins on crown gall disease in roses. The experiment was conducted on Rosa hybrida var. Mariyo in a Randomized Complete Block Design with four replications. The treatments comprised of different rates 0.5, 1, 1.5g/L of water of the product at 3% concentration applied as foliar spray and a commonly used product copper sulphate pentahydrate (Mastercop) produced by ADAMA applied at 2ml/ L as the standard and water as a negative control. Crown gall tissues were collected from four different roses per treatment from the two sites, counted and used for biochemical tests in Kabete laboratory. Bacteria were isolated by culturing and the representative colony types growing on nutrient agar media selected and sub-cultured by successive streaking on nutrient agar media. The biochemical test for the different isolates was done to identify the bacterial isolates. Application of the mixture of amino oligosaccharins and Alternaria activated protein at the rate of 1.5g/L had significant effects on galls formation and reduced the numbers significantly at both farms. The gram reaction indicated that the selected isolates were gram negative and were positive for motility, catalase, oxidase, lactose, mannitol, and salt tolerance tests. There was a significant reduction in the number of galls and size following the application of amino oligosaccharins and Alternaria fine proteins as well as improvement in plant growth. The ability to manage the disease can be attributed to enhanced defense enzyme activity enhanced by amino oligosaccharins and Alternaria fine proteins.
Highlights
The Kenyan flower industry is the third major flower exporter by value and volume just behind the Netherlands and Colombia on a global level 1 while in Africa, it is the largest producer and the leading supplier of Fair trade flowers to Europe accounting for 50-60% of total volumes.[2]
Rose plants treated with various rates of amino oligosaccharins and alternaria fine protein had mild severity rates compared with the control plots in both sites
In Winchester, there was no significance differences in plots applied with amino oligosaccharin and alternaria fine protein at the rate of 1.5g/L and plots applied with copper based fungicide
Summary
The Kenyan flower industry is the third major flower exporter by value and volume just behind the Netherlands and Colombia on a global level 1 while in Africa, it is the largest producer and the leading supplier of Fair trade flowers to Europe accounting for 50-60% of total volumes.[2]. This study sought to investigate effects of amino oligosaccharins and alternaria fine protein on crown gall disease of roses
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