Yam post-harvest and consumption - Decrease of loses and improvement of the quality of yam stored tubers and of dried products for african market

• Forschungsstelle: EU FRP
• Projektnummer: 97.0632
• Projekttitel Englisch: Yam post-harvest and consumption - Decrease of loses and improvement of the quality of yam stored tubers and of dried products for african market

Schlüsselwörter (Englisch)

Yam gibberellic acid post harvest

Alternative Projektnummern (Englisch)

EU project number: IC18-CT98-0302

Forschungsprogramme (Englisch)

EU-programme: 4. Frame Research Programme - 8.1 Cooperation with 3rd countries & intern. organisations

Kurzbeschreibung (Englisch)

See abstract

Weitere Hinweise und Angaben (Englisch)

Full name of research-institution/enterprise:
ETH Zürich
Institut für Lebensmittelwissenschaft

Partner und Internationale Organisationen (Englisch)

Cirad (F) , Uni Leuven (B) , Benin, Cote d`Ivoire, Nigeria

Abstract (Englisch)

A trial investigating the ideal time of application of gibberellic acid GA3 was repeated and the general conclusion confirmed. For both species tested, (D. cayenensis-rotundata and D. alata) the treatment in January, i.e. right after harvest, yielded the lowest losses (34% and 20% fresh matter losses 5months post harvest for each species respectively). Later treatments up to four months post harvest were less efficient (40% and 24%) but still significantly more efficient than non-treated tubers (47% and 27%). In view of the poor results obtained in 2000 compared to 1999, the post-harvest application of GA3 using different application methods (soil, gelatinised starch, soaking and split) were repeated for a third year. Only the best concentrations found in previous years were used. Soil or gelatinised starch containing GA3 as well as mechanical de-sprouting at fortnightly intervals lead to 32% fresh matter losses five months post harvest (non-treated: 45%). Soaked (150ppm/0.5hrs) tubers or tubers treated twice with soil experienced 27% and 25% losses respectively. These results are in agreement with the ones from 1999 and confirm the hypothesis mounted, i.e. that the late treatment in 2000 lead to erratic responses to GA3. The In an on-farm trial comprising 18 farmers in three main production areas of Krenglè in the Ivory Coast, the best GA3-treatments were subjected to an evaluation in the farmer's reality. The fresh matter losses were reduced respecting the tendencies in our on-station trials. Given the sample is large (9 t of yam), we may postulate that the efficiency of a GA3 treatment is not significantly altered when transferred from on-station to farmer's field. Using different prices for the inputs (GA3 and labour), the net benefit varies from -4 to +42% compared to the traditional storage. The farmers were generally impressed by the performance of the treatment and asked for GA3. Up to now the economic viability was not assessed via a model as proposed last year because the doctoral thesis leading to this model (outside the INCO-project) still awaits completion. The explorative on-farm trial in Nigeria showed that the post harvest application of GA3 leads to a significant prolongation of the dormancy in various genotypes. However, the fresh matter losses were little affected.
The presently available data on on-station and on-farm behaviour of GA3- treatment of yam will be analysed using multi-year models. Once available, an economic prediction model will be used to forecast returns of investment over time. The results are to be put together in a sensible way to form a dissertation thesis

Datenbankreferenzen (Englisch)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0632