Proc. 15th Plantation Crops Symposium PLACROSYM XV (2002). pp. 6-13.
Biochemical Markers for Rust Resistance in Coffee
AS Ram, NP Geetha, KN Amruthesh, KR Kini,D. Ganesh
CS Srinivasa, HS Shetty
Coffee is a great commodity of international trade, sustaining the economies of over eighty developing countries that produce this crop. Commercial coffee is produced from mainly two species of the genus Coffea L. viz. C. arabica L. and C. canephora Pierre. Leaf rust is a devastating disease of coffee causing economically significant crop losses of C. arabica. Thus, achieving rust resistance is one of the major objectives of almost all Arabica coffee breeding programmes of the world. Present study was undertaken with the objective of finding biochemical markers that facilitate the identification of rust resistant plants at an early stage of development (e.g. nursery stage). The enzymes phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), peroxidase (PO) and chitinase are known for their involvement in plant defense against pathogens. Present study evaluated the constitutive level of activity of these enzymes in progeny populations derived from the cross Ligenioides (natural allo-tetraploid derived from an artificial hybrid of Coffea liberica x C. eugenioides) and Hibrido de Timor (HDT, a spontaneous tetraploid interspecific hybrid of C. arabica and C. canephora) that was manifesting high rust resistance. The study was conducted on Ligenioides, HDT, their F1, F2 and BC progenies. Results indicated that PAL and LOX are good indicators of rust resistance at the constitutive level of activity and can be effectively utilized for the identification of resistant plants. This is a first report of biochemical markers with diagnostic value and utility in coffee breeding. Implications of the utilization of biochemical markers in resistance breeding and propagation and distribution of resistant material for commercial exploitation are discussed.