SENSITIVITY OF RANDOM AMPLIFIED POLYMORPHIC DNA ANALYSIS TO DETECT GENETIC CHANGE IN SUGARCANE DURING TISSUE-CULTURE

Random amplified polymorphic DNA (RAPD) analysis using 10-mer oligonuc leotide primers efficiently differentiated sugarcane cultivars and pro ved suitable for detecting gross genetic change such as that which can occur in sugarcane subjected to prolonged tissue culture, for example in protoplast-derived callus. However, RAPD analysis was not sufficie ntly sensitive to detect smaller genetic changes that occur during sug arcane genetic transformation. The length of DNA scored for polymorphi sm per primer averaged 13.2 kb, or 0.0001% of the typical sugarcane ge nome size of 1.2 x 10(7) kb (2C). RAPD analysis of sugarcane plants re generated from embryogenic callus revealed very few polymorphisms, ind icating that gross genetic change is infrequent during this tissue cul ture procedure, although epigenetic effects result in transient morpho logical changes in regenerated plants. More sensitive variations on th e RAPD technique may increase the practicality of DNA-based screening of regenerated plant lines to reveal somaclonal variants.