Professor Xiangming Xu, a scientist at East Malling Research (EMR) and this year’s winner of the Royal Horticultural Society’s Jones-Bateman Cup, discusses some of EMR’s pioneering work for the UK’s fruit-growing industry and explains how genetic advances in rice production in 1970s China has proven to be a source of inspiration for his work
Having worked at EMR for several decades, you became the leader of EMR’s Genetics and Crop Improvement Programme in 2013. How is this programme helping to secure the future supply of UK-grown fruit?
Xiangming Xu (XX): At EMR we’ve established a coherent research and development (R&D) programme that flows from primary production to the post-harvest food chain, and helps growers and retailers deliver high quality fruit to the consumer. Innovation is just as important in horticulture as it is in any other business sector – we cannot grow and market fruit tomorrow in the way that we did yesterday. With so many challenges ahead for the industry, including climate change, water legislation, new pests and diseases, energy costs and imports, it’s imperative that we have the research base here in the UK to deliver solutions, from primary production to the consumer, that are applicable to UK conditions.
Can you give us an example of one of this initiative’s stand-out research projects so far?
XX: Much of EMR's Genetics and Crop Improvement Programme is aimed at understanding the genetics of fruit quality to improve the efficiency of breeding for cultivars with high quality. The strawberry genetics work, led by Doctors David Simpson and Richard Harrison, on Verticillium wilt has been inspiring. Strawberry production in soil can now be challenging due to the banning of several effective soil fumigants. Despite much effort in identifying alternative treatments there has been no significant breakthrough.
Therefore, one of the long-term, durable, control methods is the use of resistant varieties. Although identifying resistant plant material is difficult, the team at EMR has identified and validated several [genetic] markers linked to the resistance in strawberries to the Verticillium pathogen. This has now been implemented in commercial breeding programmes at EMR.
Similarly, we’ve been carrying out research to identify host resistance to other important pests and pathogens. It’s envisaged that these findings can be built on to deliver [to the market] varieties that are resistant to economically important pests and diseases to the industry.
Are any of EMR’s Verticillium wilt-resistant strawberry varieties commercially available?
XX: Recent work at EMR has shown that Verticillium resistance does exist in some commercially available varieties, such as [EMR-bred] Finesse, which has proved popular with some growers. In the future, we will be releasing further varieties with resistance to wilt as well as to powdery mildew. We anticipate we’ll deliver such varieties in the next five or six years.
What will the wider availability of such disease-resistant varieties mean for the UK soft fruit industry?
XX: The release of varieties with improved resistance to wilt will enable growers to grow fruit without the use of soil sterilants. Varieties with resistance to both wilt and powdery mildew will enable significant reductions in crop protection inputs [such as fungicides] in both soil and protected cropping situations. This will result not only in lower inputs but also better fruit quality as growers aim for ever-greater sustainable production.
How is each sector of the fresh produce industry helping to support this type of research?
XX: Research that delivers a strong impact is usually the result of a logical flow from so-called ‘basic’ science funded by government (either through Innovate UK or the BBSRC bioscience link scheme) to industry-funded ‘applied’ science. EMR bridges this basic-to-applied science through the involvement of many producer organisations, growers, retailers, propagators, processors and the like.
What are the stand-out projects for you that you've worked on for the fruit-growing industry?
XX: Our efforts in developing computer forecasting models for key pests and diseases, and trying to demonstrate the usefulness in commercial horticulture and agriculture, is a long-term venture. The importance of using decision support systems in commercial production has been gradually recognised by the industry. Large UK producer organisations have been establishing networks of weather stations to make real-time pest/disease forecasts for decision-making. Use of these real-time forecasts is an essential component of developing long-term, sustainable ‘smart agriculture’.
Why are computer forecasting models so important to the fruit-growing industry?
XX: Modelling dynamics of pests and diseases enables us to apply the correct crop protection measures (such as pesticides) only when they are needed – this is one aspect of precision agriculture. This potentially reduces inputs throughout the year, which reduces growers’ production costs and also reduces any environmental footprint. The real value of prediction systems will be realised when we can very accurately forecast weather patterns and predict pest and disease occurrence at a very local scale. Smart agriculture is a next step in modern fruit production.
Where do you go from here with your research?
XX: Almost all science today is interdisciplinary; the speed of advances is incredibly exciting. By combining modern advances in sequencing technology with traditional soil science and crop pathology, we are beginning to develop a deeper understanding of how soil amendments and other crop husbandry techniques, such as irrigation, will affect soil microbial population structure and, in turn, how the microbial population affects crop production.
There are huge advances to be made in soil health for crop production – making crop production systems ever more sustainable. With that in mind, we’re delighted to have won recent BBSRC Horticulture and Potato Initiative (HAPI) funding for a project on apple replant disease, which is an important first step in combining these modern and traditional science techniques.
Apple replant disease has long caused frustrations for growers wanting to plant new orchards in fields where older orchards have just been grubbed. The challenge has been in accurately characterising the problem. We now understand there is a complex mix of components, including fungi (such as Fusarium spp), oomycetes (e.g. Phytophthora spp.) and nematodes. Which component is the most significant in different soils and with different rootstocks and, critically, how different components will interact is poorly understood. Though the general consensus is that nematodes only aggravate the replant symptom rather than being a causal agent, there is much work to be done over many years before the topic is fully resolved.
You trained in plant genetics and breeding at the University of Wales and, for several decades, your work focused on plant breeding and the epidemiology – that is, the patterns, causes, and effects – of plant pathogens. What first sparked your interest in this field of science?
XX: Growing up in rural China, I witnessed the amazing role that hybrid [specially-bred] rice played in transforming the outlook of food production in the 1970s. That interest in plants has been fuelled by a love of mathematics – and much of plant genetics and breeding today is based on maths and statistics. As an undergraduate, I was really interested in population genetics as at that time this subject was essentially driven by mathematics.
You’ve just been awarded the UK’s Royal Horticultural Society’s Jones-Bateman Cup in recognition of your significant contribution to scientific advances and excellence in horticultural research. First – congratulations. Second, how do you feel about receiving this prestigious accolade?
XX: I’m especially delighted to have received this fantastic award as it actually recognises the outstanding achievements of the whole [plant] pathology team at EMR over the past 20 years. It’s also extremely pleasing as the RHS Jones-Bateman Cup represents the scientific contribution of EMR to the UK fruit-growing industry.