Articles
RESEARCH AND DEVELOPMENT OF YACON (SMALLANTHUS SONCHIFOLIUS) PRODUCTION IN NEW ZEALAND
Article number
670_8
Pages
79 – 85
Language
English
Abstract
Yacon (Smallanthus sonchifolius) production is being investigated in New Zealand as a fresh root vegetable for export and for the production of processed food products, extracts high in fructo-oligosaccharides (FOS) and sweet syrups.
Yacon production is best suited to the warmer northern regions of New Zealand.
Colder temperatures and a shorter growing season limit its production in southern areas.
Establishing a crop by planting crown pieces of 180-200 g increased the plant root yield to 5 kg/plant compared to 2 kg/plant from a 50 g piece.
Root yields increased as plant populations were increased to above 24 000 plant/ha.
Narrowing the row spacing from 1.7 to 0.85 m had no effect on root yield.
Research has identified suitable pre-emergence herbicides for weed control, but there is a need for crop tolerant post-emergent herbicides.
Time of harvest trials showed that root yields increased throughout autumn until winter frosts halted growth.
FOS concentrations peaked at flowering in late autumn and then declined with an increase in mono- and di-saccharides.
FOS content, as a percentage of the total carbohydrate content, declined from 65% in mid-winter to 46% when the roots were left in the ground until November.
Storing roots at 1°C from a late winter harvest maintained FOS levels at a high level for 30 days, but after 72 days storage the levels of FOS had declined by 35%. FOS in yacon roots stored at 5, 10, and 20°C, or at ambient temperatures inside or outside, declined to an equivalent level following 15 days storage and declined still further over 72 days of storage.
Roots left in the ground over the 72-day period showed the least change in FOS levels.
Commercial lots of up to 10 ha have been planted in northern New Zealand using machine planting and harvested with modified potato equipment.
Root yields from the commercial plantings of 30-40 t/ha have not yet reached the yields of 90-100 t/ha recorded in the experimental work, but commercial yields are expected to increase as research findings are adopted.
Yacon production is best suited to the warmer northern regions of New Zealand.
Colder temperatures and a shorter growing season limit its production in southern areas.
Establishing a crop by planting crown pieces of 180-200 g increased the plant root yield to 5 kg/plant compared to 2 kg/plant from a 50 g piece.
Root yields increased as plant populations were increased to above 24 000 plant/ha.
Narrowing the row spacing from 1.7 to 0.85 m had no effect on root yield.
Research has identified suitable pre-emergence herbicides for weed control, but there is a need for crop tolerant post-emergent herbicides.
Time of harvest trials showed that root yields increased throughout autumn until winter frosts halted growth.
FOS concentrations peaked at flowering in late autumn and then declined with an increase in mono- and di-saccharides.
FOS content, as a percentage of the total carbohydrate content, declined from 65% in mid-winter to 46% when the roots were left in the ground until November.
Storing roots at 1°C from a late winter harvest maintained FOS levels at a high level for 30 days, but after 72 days storage the levels of FOS had declined by 35%. FOS in yacon roots stored at 5, 10, and 20°C, or at ambient temperatures inside or outside, declined to an equivalent level following 15 days storage and declined still further over 72 days of storage.
Roots left in the ground over the 72-day period showed the least change in FOS levels.
Commercial lots of up to 10 ha have been planted in northern New Zealand using machine planting and harvested with modified potato equipment.
Root yields from the commercial plantings of 30-40 t/ha have not yet reached the yields of 90-100 t/ha recorded in the experimental work, but commercial yields are expected to increase as research findings are adopted.
Authors
J.A. Douglas, M.H. Douglas, B. Deo, J.M. Follett, J.J.C. Scheffer, I.M. Sims, R.A.S. Welch
Keywords
root storage, crop production, fructo-oligosaccharides, plant population, storage sweetening
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