Purpose, selection, and application of descriptors for sugarcane germplasm

Abstract

Purpose, requirements, and application of morphological descriptors for use in a sugarcane germplasm collection are reviewed. Such descriptors could be used to verify the identity of cultivars, and as a measure of genetic distance. Verification of cultivar identity is essential in routine plant breeding and associated research. Genetic distance estimation would enable a better usage of available genetic resources. Morphological characters are perhaps more reflective of agronomic performance and they provide a broader sampling of the genome than molecular techniques. Statistical evaluation of characters for adoption as descriptors differs from most taxonomic studies because the population is hybrid and open, with accelerated genetic drift. The various discriminant analyses provide the optimal character selection technique. Variance components of individual characters should also be analysed to enable character improvement. Different ways of incorporating descriptor usage into the plant breeding program are discussed.