IPM to control soil-borne pests on wheat and sustainable food production

Abstract

Soil Borne Pathogens (SBPs) including the Heterodera species, cereal cyst nematode (CCN), Pratylenchus species, root lesion nematode and crown rot (CR) caused by Fusarium species, attack the roots of cereal crops resulting in a high yield loss and reduced grain quality and quantity. The damage caused by these diseases is accelerated in areas where water stress and monoculture practices dominate. Sustainable agriculture production of rain-fed crop exposed to drought, especially those growing under arid and semi-arid conditions, is being impacted by climate change due to hotter and drier soils. It is important to recognize that a plant's ability to secure adequate amounts of water is severely impacted by the destabilizing effects of nematodes and root rotting fungi on root architecture. Integrated crop health management approaches, using both modern cultivars with resistance/tolerance to these organisms, as well as, technologies that stimulate root health and growth coupled with modern nematode management strategies such as chemical, biological and cultural are needed for sustainable production in the ever-drier environments that are now a reality in many areas of the world. Resistance is environmentally friendly and biologically effective once identified. However, resistance has only been identified against one of the CCN species found in Turkey; Heterodera filipjevi. This resistance is not yet present in the varieties widely grown in the region. Therefore, alternative approaches to limit the damage caused by SBPs are needed. Extensive screening of wheat germplasm against SBPs has identified many moderately resistant germplasm in winter and spring wheat germplasm. However, CR remains a significant bottleneck in many wheat-growing areas around the world. Hundreds of wheat lines are screened annually for SBP at CIMMYT Turkey in collaboration with the Grains Research Development Corporation and many new moderately resistant to resistant lines have been identified. A number of these sources of resistance are new and previously unreported QTL's have been identified through association mapping. The new sources of resistance to the SBPs that may be useful for selecting parents and deploying resistance into elite germplasm adapted to regions where it is a problem. Nematologists, breeders and agronomists need to work together to find solution to the complex issues facing agricultural production and use multidisciplinary approaches to move forward in insuring food security for all. Recent research within the SBP program of the International Maize and Wheat Improvement Center (CIMMYT) has focused on germplasm screening, the potential of this germplasm as source of resistance, and how to incorporate the new sources of resistance into breeding programs. Breeding for resistance is particularly complicated and difficult when different species and pathotypes coexist in nature. Other current and future research will address the use of endophytic microorganisms and other cultural practices to the yield losses incurred by SBPs. There is currently insufficient breeding for resistance to SBPs due to a lack of expertise and recognition of SBPs as a factor limiting wheat production potential, inappropriate breeding strategies, slow screening processes, and increased research funding is required for a more holistic approach to plant health management.