It is becoming increasingly important that any new easy peeler hybrids we develop have a high degree of seedlessness. We have also needed to take into account the mixed orcharding approach that is used locally, where many citrus cultivars are often grown in close proximity. They will unfortunately become seedy if pollinated by another cultivar. We have chosen to use in our breeding programme a strategy for seedlessness called triploidy that will work even where cross pollination occurs. These chromosomes are located within the nucleus of a plant cell and are only visible at a microscopic level.
Polyploidy is the condition in which each cell contains three or more sets of chromosomes.
This occurs naturally in citrus, often through spontaneous mutations. Changes to the ploidy level of citrus can affect the size, habit and vigour of the tree and the quality and seediness of the fruit. The value of triploids Triploid citrus cultivars contain three sets of chromosomes and have great commercial potential because of their high degree of seedlessness. Unfortunately the frequency of naturally-occurring triploids in Citrus is low. Plant Tissue Culture Seedlessness has always been important in the selection and evaluation of new hybrids and is difficult to achieve by regular breeding methods.