Grafting technique reduces bacterial wilt incidence in eggplant

Project leader, Dr. Nenita L. Opina of the Crop Science Cluster of the College of Agriculture, UP Los Baños, indicated that when high-yielding, susceptible commercial varieties of eggplant were grafted with rootstocks resistant to bacterial wilt, reduced incidence of the disease was noted. She added, however, that the degree of resistance showed by grafted plants was dependent on the level of resistance of the rootstocks.

Bacterial wilt caused by Ralstonia solanacearum, was found to limit eggplant production in the tropics. The research team reported that in a recent survey, bacterial wilt incidence ranged from 15-30% and 95% in resistant cultivars and susceptible high-yielding commercial varieties of eggplant, respectively.

The Philrice-funded project entitled “Influence of host resistance and grafting on the incidence of bacterial wilt in eggplant” was conducted in farmer’s fields that were naturally bacterial wilt infested in Nueva Ecija, Pangasinan, and Batangas and disease nurseries of UPLB and Philrice. The high-yielding commercial varities included in the research were Casino 901 and Bulakeña Long Purple (BLP), while farmer’s variety Nueva Ecija Green (NEG) and Abar were used as scion. Bacterial wilt resistant varieties used as rootstocks were Eg 203, EG 195, S 69 and moderately resistant cultivars 89-002 and A 300.

Findings revealed that susceptible Casino 901 varieties gave significantly lower bacterial wilt infection when grafted to rootstocks Eg 203 and 89-002. Abar variety when grafted to Eg 203 failed to reduce bacterial wilt infection in UPLB nursery but not in Philrice nursery where the infection reduction was found significant.

Commercial variety BLP showed well when grafted with Eg-203 in Philrice nursery but not significant in UPLB nursery, but results were significant when BLP was grafted to 89-002 in both nurseries.

In farmer’s fields, highly susceptible NEG when grafted to Eg-203, 89-002, A 300, Eg 195 and S69 gave significant decrease in bacterial wilt infection by 46-100% in the provinces of Nueva Ecija, Pangasinan and Batangas, resulting to increase in eggplant yield. (By Rosario G. Gabatin)