Resistance sources, resistance screening techniques and disease management for Fusarium wilt in cotton

Fusarium wilt (FW), caused by the fungal pathogen Fusarium oxysporum f. sp. vasinfectum (FOV), is a significant economic constraint to cotton production worldwide. The pathogen has a wide geographical distribution, and its biological characteristics have enabled its establishment of eight races in several agro-ecosystems spanning from regions with high precipitation to semi-arid and arid irrigated zones. Management of Fusarium wilt is challenging because of the ability of FOV to persist in production systems through formation of long-lived chlamydospores and through its parasitic and pathogenic associations with cotton and other rotational cops and weeds. The interaction of FOV with nematodes constitutes additional constraints to the management of the disease. Breeding and utilizing FW-resistant cultivars has proven to be the most cost-effective control method. Numerous approaches and methods have been used in screening cotton for resistance to FW. This review provides a background on accumulated knowledge over the past two decades on sources of FW resistance and methods of screening for resistance including inoculation and evaluation protocols in cotton. The review also provides an overview of the biology and management of FOV.