Cytogenetical and Molecular Characterization of Five Commercial Varieties in Trichosanthes anguina L.

Abstract

Five commercial varieties of Trichosanthes anguina (Snake Gourd), namely Turag, Dhaka Green, Super Long Green, Anika and Apurbo, were investigated cytogenetically and at the molecular level for authentic characterization. The variety Super Long Green was found to possess 2n=23 chromosomes and considered as a primary trisomic. 2n=22 chromosomes were found in the other 4 varieties. The total length of the 2n chromosome complement was largest in Anika and smallest in Apurbo. Only one extra large chromosome was found in Turag and Anika suggesting it had either been transferred from different genome or was a case of repeated duplication. No decrease in chromosomal length was found in Turag, a moderate decrease was found in Dhaka Green and Anika, and a sharp decrease in Super Long Green and Apurbo. A pair of satellites was found in Turag. Only a stain specific satellite was found in Dhaka Green. No CMA band was found in Turag and Super Long Green. The other 3 varieties showed distinct CMA banding pattern in respect of number, size, location and percentage of GC-rich area. The 5 varieties showed distinct RAPD bands with 6 different primer combinations. In addition, the Apurbo and Turag varieties showed unique DNA fragments with the primer combinations OPA-3 and OPA-4 respectively. A combination of cluster and karyotytpe analysis clearly indicated that Turag and Apurbo were distinctly related from the other 3 varieties. Therefore, with the help of cytogenetical and RAPD analysis, it was possible to characterize each variety.