Identification of resistant sources of jute (Corchorus olitorius L.) against stem rot caused by Macrophomina phaseolina (Tassi) Goid.

Abstract

Stem rot of jute (Corchorus olitorius L. and C. capsularis L.) caused by Macrophomina phaseolina (Tassi) Goid. attacks all parts of plant and incites disease from germination to crop maturity producing symptoms, like, damping off, seedling blight, leaf blight, stem rot, collar rot and root rot of the fibre crop and pod or seed infection of the seed crop. None of the tossa (C. olitorius) jute varieties has so far been reported to be tolerant to stem rot disease. Hence a study was undertaken during 2006-08 to identify C. olitorius germplasm accessions tolerant to M. phaseolina at Ramie Research Station, Sorbhog, Assam known as ‘the hot spot’ for the disease. During first year, 293 germplasm accessions including short listed ones from earlier study and new collection were tested along with 2 check varieties viz. JRO 632 and JRO 524 and 19 were selected on the basis of percent disease index (PDI). These 19 and 2 check varieties were further evaluated during 2007 and only 8 accessions were selected. These lines, namely, OIN 107, OIN 125, OIN 154, OIN 157, OIN 221, OIN 651, OIN 853 and OIJ 084 and two check varieties were grown for rigorous screening during 2008. The two check varieties showed higher PDI during three consecutive years. Only four accessions namely OIN 125, OIN 154, OIN 651 and OIN 853 showed moderately resistant reaction based on mean PDI 5.0 or less and were finally selected. The reaction of these 4 entries was also confirmed in pot culture tests.