Ipomoea (Sweetpotato/Kumara) Post-Entry Quarantine Testing Manual

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1. SCOPE The scope of this manual is limited to Ipomoea batatas and Ipomoea setosa nursery stock (whole plants and plants in tissue culture), seed for sowing and pollen of Ipomoea species permitted entry into New Zealand as listed in the Ministry for Primary Industries (MPI) Plants Biosecurity Index (http://www.maf.govt.nz/cgi-bin/bioindex/bioindex.pl). At the date of publication of this manual, these species were as follows: Ipomoea alba Ipomoea aquatica Ipomoea arborescens Ipomoea batatas Ipomoea brasiliensis Ipomoea cairica Ipomoea carnea Ipomoea horsfalliae Ipomoea imperialis Ipomoea lobata Ipomoea minuta Ipomoea nil Ipomoea Post-Entry Quarantine Testing Manual · November 2012 Ipomoea noctiflora Ipomoea palmata (syn. Ipomoea cairica) Ipomoea pes-caprae Ipomoea platensis Ipomoea purpurea Ipomoea quamoclit Ipomoea sepacuitensis Ipomoea setosa Ipomoea sloteri Ipomoea tricolor Ipomoea tuberosa (syn. Merremia tuberosa) Note: The importation of Ipomoea caerulea, Ipomoea hederacea, Ipomoea indica, Ipomoea learii (syn. Ipomoea indica), Ipomoea plebeia and Ipomoea triloba is prohibited. This manual describes the testing requirements specified in the import health standards for Ipomoea. The manual also provides an introduction to the crop and guidance on the establishment and maintenance of healthy plants in quarantine. 2. INTRODUCTION Sweetpotato (Ipomoea batatas (L.) Lam.), a member of the family Convolvulaceae, probably originated in Central or South America, where it has been a food source for over 55,000 years. Sweetpotato was taken to Spain and early Spanish explorers are believed to have taken it to the Philippines and East Indies; from there it was soon carried to India, China, and Malaysia by Portuguese voyagers. It is not fully known how sweetpotato arrived in Polynesia, but it has been used on many of the islands in the South Pacific Ocean for at least 2000 years (Clark & Moyer, 1988). Sweetpotato is grown in a wide range of environments under a range of farming systems, from the humid tropics to mild temperate zones, and from sea level to 2700 m altitude. Annual global production of sweetpotato currently exceeds 124 million tonnes. More than 95% of the global sweetpotato crop is grown in developing countries. China is the world's largest producer, accounting for more than 90%. Vietnam, Indonesia, and Uganda all grow more than two million tonnes per year. India and Rwanda each harvest more than a million tonnes annually. Of the 82 developing countries where sweetpotatoes grow, 36 are in Africa, 22 in Asia, and 24 in Latin America. Around 40 countries count sweetpotato among the five most important food crops produced on an annual basis. 1
The per capita income provided by sweetpotato is one of the lowest among the major food crops. Its potential benefit to poor farm households and urban consumers is only now being considered. Sweetpotato actually produces more edible energy per hectare per day than any other major food crop. Sweetpotato is a perennial plant cultivated as an annual crop and propagated vegetatively. The sweetpotato plant is a prostrate vine system that expands horizontally and develops a shallow canopy. The sweetpotato plant produces several different types of thick and thin roots. Thick roots can differentiate into either ‘pencil roots’ or ‘storage roots’, the latter being used for human consumption. Sweetpotatoes are not tubers as they are initiated at the first stem node below the soil line, to which they are attached by a stalk of thinner root (Clark & Moyer, 1988). Although known for its tolerance to drought and its sensitivity to saturated soil condition, sweetpotato requires sufficient water and nutrients to produce good yield. Non-rooted stem cuttings (20-40 cm) with 5-8 nodes are harvested from storage roots laid out in nursery beds, and transplanted into the field. Sweetpotato can be cultivated continuously throughout the year in tropical regions, but in temperate regions the crop is planted in spring when the risk of frost is reduced. The crop requires a minimum frost-free period of 120-150 days and average daily temperatures of 22-24ºC along with good rainfall and good drainage (Clark & Moyer, 1988). The flesh of sweetpotato can be white, purple, orange or yellow. Yellow and orange-fleshed varieties are valuable for their carotene (provitamin A) content. Skin colour ranges from nearly white through shades of buff to brown, or through pink to copper, even magenta and purple. In New Zealand, sweetpotato (known as kumara) is a crop of cultural importance and an important food source. Kumara was introduced by Maori when they settled in New Zealand from Polynesia. Cultivation of this crop was undertaken on a large scale because of its importance as a food source. With the arrival of European settlers, other carbohydrate crops such as potato, wheat, and corn displaced sweetpotato in dietary importance but not the crop’s place in Maori culture. Since the 1950s, after efforts to select improved clones, production has steadily increased along with consumption as people rediscover kumara. The local cultivar Owairaka Red, released in 1954, comprises 80% of the crop. Other cultivars include Toka Toka Gold, selected in 1972 (14%) and Beauregard (introduced in 1993). A range of other local varieties are also grown, usually in garden plots. The area around Dargaville in the Kaipara district produces 85% of the national crop. Smaller plantings of approximately 5% are found around Auckland and Bay of Plenty. The area planted annually is approximately 1,100 hectares producing about 26,500 tonnes, with yields averaging 20 t/ha. Plantings range in area from garden plots to 30 ha, averaging 10 ha. Most of New Zealand’s production is for local fresh consumption although increasing amounts are processed and/or exported. A thorough review of this crop and its place in New Zealand agriculture is presented by Lewthwaite (1997). Ipomoea Post-Entry Quarantine Testing Manual · November 2012 2
Page 1 and 2: Ipomoea (Sweetpotato/Kumara) Post-E
Page 3: 1.7 Dickeya chrysanthemi ..........
Page 7 and 8: Viruses: Sweetpotato chlorotic flec
Page 9 and 10: 7. TESTING Each of the specific tes
Page 11 and 12: 7.1.1 Graft inoculation Each I. bat
Page 13 and 14: 7.1.2 Herbaceous indexing Each I. b
Page 15 and 16: Table 2: Source of antisera and pos
Page 17 and 18: 7.1.3.2.1 Virus reverse transcripti
Page 19 and 20: Recommended method for RNA viruses:
Page 21 and 22: Positive control material, in the f
Page 23 and 24: The reaction and cycling conditions
Page 25 and 26: (a) Primers recAF/recAR (Waleron et
Page 27 and 28: 8. CONTACT POINT This manual was de
Page 29 and 30: Nassar, A; Darrasse, A; Lemattre, M
Page 31 and 32: . 1.5 Streptomyces ipomoea (a) (b)
Page 33 and 34: Appendix 2. Virus symptoms on graft
Page 35 and 36: Appendix 3. Protocols referenced in

Ipomoea (Sweetpotato/Kumara) Post-Entry Quarantine Testing Manual

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