The quikgro potato; an early maturing multiple stress tolerant potato crop for sub-Saharan Africa

Lead Research Organisation: University of St Andrews
Department Name: Biology

Abstract

Potato is a most important staple food and cash crop contributing both to food security and the local economy in countries of sub Saharan Africa (SSA) such as Kenya and Malawi. It is grown mainly by small holder farmers in the highland regions (>1500 m asl) since tuber development requires cool temperatures. Demand for potatoes is growing and the major challenge is to develop local varieties adapted to agronomic and environmental conditions found at lower altitudes to expand the production areas. Key to our proposal is to combine stress tolerance (biotic and abiotic) with the development of early maturing cvs (EMCs) (reaching full maturity in 60-70 days "the Quikgro potato" compared with over 100 days for most commercial varieties). We expect that EMCs will produce tubers that bulk quickly in warmer environments, mitigating the effect of short rainy seasons and droughts. EMCs will also be less susceptible to disease (due to a phenomenon called mature plant resistance; MPR) and the shorter growth cycle would allow potato to fit in rotation with other crops such as rice and wheat. Thus this innovation would have multiple benefits for the people of SSA.
Breeding potatoes to obtain germplasm with improved stress tolerances has proved very difficult as potato is tetraploid (it has 4 sets of each chromosome) and exhibits complex inheritance patterns making it a very long term process to achieve improvements in such genetically complex traits. Our approach is to avoid stresses by developing potato varieties that mature early (within 70 days) as our preliminary data indicates that this trait is controlled by a few dominant genes making it a more amenable breeding target.
Advances in understanding the control of tuber formation in potato have defined some of the components of day length signalling that lead to tuberisation such as the discovery of an additional version of the gene (StSP6A) that is associated with tuber formation under long days. Additionally, in transgenic tester lines, silencing of a gene encoding CEN1/TERMINAL FLOWER1, significantly decreases the time to both tuber and flower initiation. Thus the presence of a particular allelic variant impacts on the timing of tuber initiation providing a novel breeding strategy to develop early maturing potatoes. In further work (funded by ERA CAPS Hotsol BB/M004899/1) we have identified a gene that (designated StHot1) that confers extreme heat tolerance when tested in model systems.
Virus diseases are a major constraint of potato production systems in Kenya and Malawi. Mature potato plants are known to develop resistance to disease as they age (MPR). Our recent investigations (funded by BBSRC BB/L011840/1) have shown that resistance is induced at the onset of flowering, therefore, we hypothesise that early maturing plants will be more virus resistant. In addition, viruses can be controlled by natural resistance genes and previously we have identified natural resistance to potyviruses in the potato types (described above) that have also been studied for earliness and tuberisation. The resistance, has been genetically mapped and a marker developed. Using our network of established contacts, we introduced a virus resistant cultivar Mayan Gold containing this resistance to Kenya. Mayan Gold passed Kenyan National Performance Trials and since release has proved highly successful.
We will investigate the function of the newly identified gene targets to achieve proof of principle that EMC's will avoid both abiotic and biotic stresses. We shall screen a range of germplasm to test whether potato lines containing markers for earliness and stress tolerance will perform better in the African environment. Exchange with SSA scientists will enhance expertise in modern breeding and diagnostic technologies. Networks will be strengthened to engage all local stakeholders for knowledge exchange and feedback to translate findings into acceptable and practical outcomes.

Technical Summary

In potato, tuber yield is highly sensitive to biotic and abiotic stresses which limit production in climatic zones experienced in sub-Saharan Africa and parts of Asia. Recent developments by researchers at St Andrews University and the James Hutton Institute have identified allelic variants that protect the plant from the harmful effects of heat and virus. Elevated temperature tolerance is achieved by the presence of an allele of an HSc70 gene that is expressed at much higher levels than other alleles at elevated temperature. Using a genetic approach, a locus has been defined that is associated with virus resistance. Our recent research has also characterised mature plant resistance to virus. An important part of our strategy to develop potatoes with combined heat and virus tolerance is to produce early maturing varieties that escape the effects of abiotic stress and will also be protected from virus by developing mature plant resistance earlier in the growing season. We have demonstrated that by silencing CENTRORADIALIS/TERMINAL FLOWER 1, transgenic lines tuberise and initiate flowers much earlier (by ca. 20 days) than controls. This finding will add an important element to published tuberisation models and will enable hypotheses about mature plant resistance to be tested.
KASP markers will be developed for allelic variants of the genes that impact on tuber maturity, heat tolerance and virus resistance. By extensive phenotyping and genotyping of potato populations in Malawi and Kenya we shall build quantitative genetic models relating allelic composition to phenotype and develop predictive tools to identify the most beneficial combinations of alleles. Outreach activities to crop scientists (including training of African scientists), stakeholders in the potato production and value chain and policy makers will amplify the impact of the research and opportunities for application.

Planned Impact

Introduction: The underlying thrust of the proposed research is to develop a new concept that builds on our recent findings about tuberisation and stress tolerance in potato, the world's third most important food crop. Currently, a combination of biotic and abiotic stress decrease yields and constrain production to the cooler highland areas of sub-Saharan Africa (SSA). The outcomes of this project will be new knowledge, genes and alleles that can feed into a delivery framework that can be used in breeding programmes to increase tuber yield in warmer lowland environments.
Who might benefit from the proposed research? The DAC countries that will directly benefit from this foundation award are Malawi and Kenya. However, if the objectives of the proposal are realised then countries in SSA (such as Uganda, Tanzania, Rwanda, Zimbabwe, DRC) and Asia would benefit as 'Quikgro' potato is relevant to their production systems. Potato is an important food and cash crop in SSA grown predominantly by small holder farmers. In Malawi it contributes to food security especially during the hunger months (November to February) and in Kenya it is the second most important food crop after maize. Potato is a valuable alternative to reduce the dependence on maize as it is more nutritious (yielding 2-4 x the food quantity per ha than cereals, can meet the daily human dietary requirement of protein, vitamin C, zinc and iron, and uses water more efficiently). Therefore, the crop has strategic value in decreasing hunger and malnutrition. Furthermore, potato is not susceptible to commodity market speculation. In Kenya potato is cultivated by over 500,000 mostly small holder farmers with annual production worth about KSh50 billion. The industry has a strong multiplier effect, indirectly employing about 2.5 million people. National per capita consumption is expected to grow at 5.2% annually, with urban demand exceeding 7%, for the next 10 years to >40kg per capita by 2022. Thus potatoes have significant potential to contribute to food security and income generation but current yields of approx 20t/ha are far below the potential. Malawi has about 2 million small-holder farmers and there is a recognised over dependency on maize, potato is at the forefront of the Government's crop diversification efforts. The market for potato is expanding rapidly because of urbanization. This growing domestic market presents a valuable livelihood opportunity for smallholder farmers besides benefiting vulnerable low-income consumers. The annual national production statistics show potato production doubled from 527,830 MT in 2006 to 1,065,833 MT in 2015, and potato yield has increased by 33%, from 13.0 MT/ha to 17.3 MT/ha (a period which overlaps with Irish Aid's and the Scottish Government's (PI Torrance grant) first investments in strengthening the potato sector).
How might they benefit from this research? Maximum impact will be achieved as the project combines cutting edge research in the UK with an established network of scientists in Malawi (Mwenye/Demo) and Kenya (Were) working with farmers clubs and cooperatives. Each club represents several hundred farmers and other stakeholders in many counties and districts (at least 1000 in each country). The clubs are key centres for engagement, knowledge exchange and gaining information on farmer and industry preferences. Importantly, the networks of farmers associations are already established and growing (resulting in successful implementation and improved potato cultivation in previous projects). The associations and clubs will be boosted by the capacity building, knowledge exchange and demonstrations supported by this grant. The impact pathway will involve development of a delivery framework for technologies and a roadmap for further exploitation including plans for industry-led actions. This will positively impact on yields, farmers' incomes (and livelihoods) and growth across the whole value chain.

Publications

10 25 50
 
Description All objectives for the project have been met; We have studied the impact of CEN-1 on the tuber life cycle and responses to biotic and abiotic stresses. We have data that demonstrates how allelic variation in StCEN may be utilised in breeding potato varieties with modified tuber life-cycle traits. Understanding the mechanism of tuber initiation in potato provides a key route to increasing productivity of a crop that is essential for food security. We have identified potato diploid genotypes that contain combinations of alleles that impact on tuber maturity, heat stress tolerance and virus resistance. Sixty genotypes were selected from the 06H1 population according to possession of PVY resistance and allelic composition of HSc70 (stress tolerance) and CEN-1 (earliness) genes. Tubers of these genotypes were planted in a randomised plot design at three Malawi sites in early January and three Kenyan sites in March 2018 and again in 2019. Plants were harvested at days 40, 70 and ca. day 120. Using data generated from the African field trials, a subset of 12 high performing 06H1 genotypes, containing different combinations of the CEN-1 and HSc70 alleles, demonstrated resistance to late blight and fully mature after 70 days of growth were selected for further study in a second award.
Exploitation Route A further funding award via GCRF has been successful to continue the study of the 12 superior genotypes and conduct participatory selections with African stakeholders and other actors along the value chain
Sectors Agriculture, Food and Drink,Education

 
Description Our network of collaborators in Kenya and Malawi has been greatly strengthened during the course of this project. There have been two visits to Malawi (Feb 2018, March 2019). The initial meeting established project plans and field visits. The second visit included a farmer field event in which the Makoka trial was demonstrated to 114 local farmers, many expressing a strong interest in obtaining potato planting material. Moreover, the Zomba District Agricultural Development Officer (DADO) has decided to include potato in the portfolio of crops in the Agricultural Sector Wide Approach.multi donor trust fund (ASWAP) Project. A field day and planning meeting was conducted in Kenya in May 2019. A field day in the Kakamega region of Kenya attracted interest from ca. 100 small-holder farmers and was featured on TV news in Kenya. With our African partners we have begun to promote potato production in non-traditional areas and with additional funding gained from the results of this award we will continue to support the activities to boost adoption of cultivars suited to growing in the regions and so economic development.
First Year Of Impact 2018
Sector Agriculture, Food and Drink,Education
Impact Types Economic

 
Description A new model for potato tuber initiation and yield development (POTENT)
Amount € 337,400 (EUR)
Funding ID 835704 
Organisation European Union 
Sector Public
Country European Union (EU)
Start 05/2019 
End 04/2022
 
Description Food Security and Health for East Africa
Amount £1,103,777 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start  
End 03/2021
 
Title Transcriptomic data related to tuberisation in potato 
Description Transcriptomic analyses were performed using a custom Agilent microarray containing probes representing transcripts of all 39,031 protein coding genes predicted from the potato genome sequence (The Potato Genome Consortium, 2011). We compared transcriptional profiles in non-tuberizing stolons from transgenic lines generated in Quikgro and controls. A striking feature of the set of strongly up-regulated transcripts in transgenic lines that tuberise ealier is the presence of germin associated transcripts. Transcripts annotated as germin 3, 4 and 12 are expressed at levels between ca. 200 and 700-fold higher in the stolons from RNAi lines than in those from controls. This information provides new insights into the tuberisation process and will be the subject of further research. This dataset will be made available once the results are published in an open access journal. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? No  
Impact These results will be the subject of further research and have the potential to greatly increase our understanding of the tuberisation process. 
 
Description Conference presentation 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact A presentation entitled "The genetic control of sprout growth in potato tubers during storage" was given by Mark Taylor at "The Global Potato Conclave" help in Gujarat, India in January 2020. The conference was attended by over 500 registered participants from academia, industry and policy. The was considerable interest in Quikgro" results with contacts made with industry partners, keen to evaluate some of the Quikgro genotypes under Indian conditions.
Year(s) Of Engagement Activity 2020
URL http://gpc2020.in/
 
Description Interview for National News 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact A press conference was held at the Potatoes in Practice Event Thursday 9th August Balruddery Farm, Tayside. At a press breakfast, research in the Quikgro project was described - particularly relating to developing climate resilient potatoes. The breakfast was attended by approximately 30 press members and resulted in wide publicity for Quikgro research. This was featured in articles in the Dundee Courier (10th August) and the Sunday Times (19th August).
Year(s) Of Engagement Activity 2018
URL https://www.thetimes.co.uk/article/scientists-hot-potato-find-will-save-tatties-from-baking-during-h...
 
Description Visit to Xisen Potato Company Ltd 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Visit to Xisen potato company where discussions were held with Dr Xie (R&D director), Dr Hu (Managing director) and Mr Liang (owner). L Torrance gave a talk to company technical staff and visited sites in Shendong province, Inner Mongolia and Beijing.
Year(s) Of Engagement Activity 2017
 
Description Workshop on Potato's technology Nairobi Kenya 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The workshop was held to raise awareness of new innovations in potato technologies (results of research, traits of different potato cvs, pest and disease problems) among Kenyan farmers, plant health officials, seed producers and NGO.
Year(s) Of Engagement Activity 2018