Summary of Awards to Date

Development of virus resistant sweetpotato varieties through biotechnology approach.

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Sep. 1, 2008 - Aug. 31, 2011

Award Number


Funding Agency

Center for Produce Safety

Amount Awarded



Franklin Jackson, Ph.D.
Alcorn State


Zhang, S., Njiti, V.N., Ming, G., Xia, Q., Igbokwe, P., Rajanna, B.


Sweet potato production is a major agricultural business in the southern U.S., valued at $283 million which represent 75% of the U.S. growing sweet potatoes. In Mississippi, sweet potato is a major horticultural crop valued at $49 million, which makes Mississippi the third in the U.S. Current cultivars are bred for fresh consumption. Efforts are being made to expand the utility of sweet potato. This will provide great opportunities for small farmers with enormous economic promise in Mississippi. However, viral infection is one of the main factors limiting the release of the full potential of sweet potato production. Viral infections can result in 30-50% yield reduction. Among sweet potato viruses in the U.S., Sweet potato leaf is considered to be the most detrimental to production. The incidence of SPLCV in the U.S. has dramatically expanded in recent years including Mississippi. SPLCV infection reportedly resulted in 25-30% yield losses to the cultivar `Beauregard' which accounts for about 80% of the U.S. production. Sweet potato viral diseases are the most difficult to control because of the lack of effective viral resistant varieties, cultural practices, and virus-killer chemicals. The advanced knowledge of the molecular mechanisms of plant-virus interactions has led to the development of novel techniques to develop cultivars that are resistant to viruses. Biotechnology provides the opportunity to translate these emerging technologies to applicable products such as viral resistant varieties. We propose to explore new technologies to develop viral resistant sweet potato varieties to address this crucial issue in Mississippi and the southern U.S. Indeed, engineering viral resistance has been achieved in papaya which has saved the U.S. papaya industry. Currently, engineered viral resistant papayas represent 53% of the U.S. production. The major impacts of the proposed project are summarized as follows: (1) the availability of viral resistant sweet potato varieties developed in this project will significantly increase its marketable yield and the income of small farmers in Mississippi and the southern U.S.; (2) it will circumvent the drawbacks, e.g., high cost and inconvenience of virus-tested `seeds' that have to be purchased annually; (3) it will make sweet potato production less dependent on pesticides which will reduce the production costs and health risks to farmers as well as to consumers; (4) the technology used in sweet potato can be explored to engineer viral resistance in other economically important crops transformable; (5) wide extension of disease resistant crop varieties will help to sustain an environmentally-friendly and sustainable agricultural system and promote responsible environmental stewardship; (6) the success of this project will enhance the reputation of ASU and will steer a wave to attract bright high school students who want to study agricultural sciences and strengthen ASU's outreach and extension programs; (7) it will enhance ASU's educational and research capacity; and (8) our positive results will benefit scientists, extension agents, and educational institutions, nationally and internationally.