The use of resistant varieties in an integrated management of epidemics of Fusarium Wilt Tropical Race 4 in the Philippines

Gus Molina, Emily Fabregar, Noel Perpetua, Benny Corcolon, Lorna Herradura, Susan Razo and Vida Grace Sinohin

Dr. Agustin Molina, Senior Scientist and Regional Coordinator for Asia and the Pacific of Bioversity International, presenting a keynote paper entitled, “The use of resistant varieties in an integrated management of epidemics of Fusarium Wilt Tropical Race 4 in the Philippines” in the CORBANA-ACORBAT International Banana Congress (April 2016) in Miami, Florida, USA

With Dr. Molina is a part of Philippine delegation to the congress that included senior officers of TADECO, headed by Mr. Vincent Floirendo (Chief OPerating Officer)and Dr. Benny Corcolon (VP of Research and Technical Services), Dr, Emily G. Fabregar, Director of Research of Lapanday Fruits Corp, Dr. Lorna Herradura, Chief BPI-Davao. Not in the photo are Mr. Stephen Antig (Executive Director of the Philippine Banana Growers and Exporters Association), and Dr. Noel Perpetua (Director of Research, Dole-Philippines).

Epidemics of Fusarium Wilt caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4) in Cavendish plantations in the Philippines (Molina et al 2008) is a serious concern to the sustainability of the Philippine banana industry. Philippines is the major banana exporter in Asia with its more than 80,000 hectares of Cavendish plantations, grown by both big companies and small Cavendish growers. Small growers are more vulnerable because they lack technical and financial capabilities to contain the disease compared to big growers. Although there is no accurate industry data of the actual extent of epidemics, the association of small growers reported that about 3,000 hectares are abandoned due to severe infection, and around 6,000 hectares are infested in various levels of incidence. Disease scouting, eradication of infected plants by burning, fallow and replanting of susceptible commercial variety, coupled with in-farm quarantine is a general disease management approach. Such approach slowed down epidemic build up especially for big plantations, but small growers are less effective eventually resulting to severe epidemics and abandoning of farms. These farmers subsequently shifted to other low-income crops. Big companies expanded new production in disease-free areas to cover increasing market demands and areas that were abandoned due to Foc TR4. Exclusionary measures such as fencing in and strict quarantine-disinfestation measures are implemented to prevent incursion in these newly established plantations. Some were successful, while others were not. Containing build up of epidemics in infested plantations is extremely difficult to achieve. The use of resistant variety finds a place as a part of the integrated approach of disease management.. Foc TR4- resistant Giant Cavendish Tissue Culture Variants (GCTCVs), are becoming practical options in managing epidemics of Foc TR4 in commercial plantations. Shared by Taiwan Banana Research Institute (TBRI), Bioversity International carried out a series of field evaluations in public-private partnerships. Two GCTCV varieties, namely, GCTCV 218 and GCTCV 219 proved to be the most acceptable options in managing Foc TR4 epidemic. In commercial trials these varieties remained resistant even after 4 ratoons, while Gran Naine became severely infected even in the primary crop. GCTV 218, moderately resistant to Foc TR4, is more acceptable by growers. It has big bunches thus good box stem ratio, and fruit quality as good as Gran Naine. Fruits can be packed and ripened together with Gran Naine, and acceptable in current markets. Agronomically, GCTCV 218 is taller than Gran Naine, similar to Tall Williams, but has longer maturity by two to three weeks. GCTCV 219, a variant of another resistant GCTCV 119, is highly resistant to Foc TR4. It is recommended for the rehabilitation of severely affected and abandoned farms of small growers. While GCTCV 219 is resistant and has sweet fruit thus has an opportunity for a special market, its bunch and agronomic characteristics are more inferior than that of GCTCV 218 and Gran Naine. GCTCV 219 is taller, longer maturing, less box-stem ratio and more of a floater thus prone to yield decline with time. Growers are satisfied with the level of resistance of GCTCV 219, but productivity and fruit quality are main concern. The use of GCTCV 218 is now gaining wider acceptance by banana companies. The Philippine government launched a $ 2.2 million programme to help small growers to rehabilitate affected farms and sustain livelihoods by an integrated approach around the use of GCTCV 218 and 219. The planting of these varieties with tissue culture seedlings in commercial scale provides an opportunity to select for improved phenotypes. While prevention of incursion to unaffected areas is the fundamental approach of Fusarium Wilt management, where epidemics are causing damage in banana plantations, the use of available resistant variety is the only major option to manage the epidemics. In the absence of other varieties from other breeding programmes, the GCTCVs seem to be the best our farmers could have at this time to save their livelihoods

Keynote paper presented during the CORBANA-ACORBAT International Banana Congress. Hyatt Hotel Regency, Miami Florida. April 20-22, 2016.