Cotton Ramulosis (Gossypium hirsutum) is an important disease affecting cotton

plantations in Brazil, and its causal agent, Colletotrichum gossypii var. cephalosporioides (Cgc),

according to the Brazilian phytosanitary authority, was considered a regulated non quarantine

pest. It makes this microorganism subject to standardization in seed certification programs.

The current seed health testing for detecting that pathogen in seed samples does not provide

reliable results for routine analysis. On this paper, attempts were made to design specific primers

for detection of Cgc associated with cotton seed. Two primer sets were selected based on the

analysis of a multiple alignment of gene’s sequence encoding the glyceraldehyde 3-phosphate

dehydrogenase from Cgc, C. gossypii and reference strains of the C. gloeosporioides species

complex. The conserved sites unique to Cgc strains were used to design specific fragment

of 140 bp. The primer specificity was confirmed by using other fungi. The primers produced

a detectable band of target DNA of Cgc in all inoculum potentials of the pathogen artificially

inoculated by the water restriction technique. The developed primer pair represents, therefore,

a reliable and rapid mean to diagnose the Ramulosis agent in cotton seed.