Genetic diversity of Fusarium spp. inciting rhizome rot of ginger and its management by PGPR consortium in the western Himalayas

The genetic variability of 32 Fusarium isolates from diseased ginger rhizomes from the Western Himalayas in India was analyzed by the unweighted pair group method with arithmetic averaging using randomly amplified polymorphic DNA amplicons. Two major clusters formed, one dominated by Fusarium oxysporum and the other by Fusarium solani. Talc-based formulations of the plant growth promoting rhizobacteria (PGPR) strain XXBC-TN (Bacillus subtilis) and a mixture of S2BC-1 (B. subtilis) with TEPF-Sungal (Burkholderia cepacia), which inhibits F. oxysporum and F. solani, were developed for rhizome dressing and soil application in ginger fields. The strain mixture recorded the maximum rhizome production (85.2%) with fewer yellows and reduced rhizome rot incidences (87.8% and 88.4%) over the control in a polyhouse. This was associated with an increase in the defense enzymes chitinase, beta-1,3-glucanase, and polyphenol oxidase. Furthermore, the strain mixture treatment promoted plant growth and enhanced rhizome production by 45.8%. In field experiments, the PGPR strain mixture reduced yellows and rhizome rot incidences by about 50.5%, which was comparable to that of a carbendazim and mancozeb fungicide mixture. (c) 2013 Elsevier Inc. All rights reserved.