Assessment of pre- and post-harvest anti-sprouting treatments to replace CIPC for potato storage

To avoid losses from sprouting during potato storage, the anti-sprouting agent chlorpropham [CIPC] has been widely used over the past few decades. However, the European Union recently decided not to authorize the renewal of CIPC, prompting the value chain to find alternative treatments. We assessed for three years the potential of pre- and post-harvest anti-sprouting treatments to replace CIPC using four potato-processing varieties. Pre-harvest application of maleic hydrazide [MH] and post-harvest applications of 3-decen-2-one, 1,4-dimethylnapthalene [1,4-DMN] and CIPC were performed following supplier’s recommendations. In addition, we evaluated the potential of 3-decen-2-one and 1,4-DMN to prolong the efficacy of pre-harvest MH treatment anti-sprouting activity during storage. All molecules significantly reduced sprouting after seven months of storage compared with the untreated control group. MH, 3-decen-2-one, 1,4-DMN and CIPC displayed respectively 86.9 %; 77.9 %, 73.6 % and 99.8 % of efficacy to control sprout weight and 79.4 %; 73.4 %, 68.4 % and 96.9 % of efficacy to control sprout length. Our results suggest that using 3-decen-2-one and 1,4-DMN in combination with MH do not bring additional benefit to control sprouting. Because differences in dormancies could be observed between varieties, we also showed that the efficacy of post-harvest treatments is genotype-dependent, while MH pre-harvest treatment is effective equally for all varieties. Applications of CIPC and MH led to detectable residues in tubers, while no residue of 1,4-DMN has been detected in tubers treated with this molecule (< LOQ). We concluded that treatments with MH, 1,4-DMN and 3-decen-2-one are valuable alternatives to CIPC to control sprouting of processing potatoes

Identification of potato varieties suitable for cold storage and reconditioning: A safer alternative to anti-sprouting chemicals for potato sprouting control.

peer reviewedLow temperature storage as an alternative to anti-sprouting chemicals in potato storage may induce reducing sugars (RS) accumulation (i.e. glucose and fructose) in potato tubers. This phenomenon is called "cold induced sweetening" (CIS) and occurs in certain varieties. CIS leads to a decrease in the organoleptic qualities and darkening of processed potato and the accumulation of toxic molecules such as acrylamide. To identify potato varieties suitable for storage at low temperatures, we screened six commercial processing varieties: Lady Claire (LC), Verdi, Kiebitz (KB), Pirol, Agria and Markies for their CIS characteristics and sprout-forming potential after storage at 4 °C and 8 °C. Our findings reveal that 4 °C storage allows for efficient sprout reduction in all six tested varieties for up to 4.5 months of storage. Three CIS-resistant varieties, namely Verdi, Lady Claire and Kiebitz, were identified as able to be stored for up to four months at 4 °C with limited increase in glucose content. Conversely, Pirol, Agria and Markies showed an increase in glucose content with a decrease in storage temperature and can be considered as CIS-susceptible varieties. After processing into crisps, the CIS-susceptible varieties displayed poor crisp color quality (brown to black color crisps) after storage for two months at 4 °C compared to the storage at 8 °C, whereas the CIS-resistant varieties had good crisp color quality (pale yellow color crisps) after storage at both 4 and 8 °C. Interestingly, the trends of total RS and/or glucose content in the CIS-resistant and in the CIS-susceptible varieties were correlated with the trends in Vacuolar Invertase (VInv) gene expression for most varieties, as well as with the trends in acrylamide content after processing. In addition, reconditioning of Markies variety after storage at 4 °C by gradually increasing the temperature to 15 °C resulted in a significant decrease of VInv transcript levels (reduction of 80 %), acrylamide content (reduction of 75 %) and glucose content when compared to a storage at 4 °C without reconditioning. Those results demonstrate that the reconditioning technique is a key factor for a sustainable potato storage and for improving the quality of processed potatoes

Prédiction de la dormance des pommes de terre pendant le stockage

Potato sprouting during storage occurs after a break in dormancy, leading to a decrease in quality and consequently economic losses. We used 3379 records from multi-year and multi-environment trials of 537 potato varieties to identify the main factors driving potato dormancy and to develop predictive models for an efficient sprouting forecast. The variety explained the majority of the dormancy variability (60.3%), followed by the year (13.9%) and the location (5.4%). About 250 predictors were considered to develop a predictive model of potato dormancy. The selected model had a validation precision of 14.59 days; it used the variety class and the sum of the daily maximum temperatures in the air during the period from planting to harvest as predictors. The predictions of the selected model were supported by results of the in vivo trial using dormancy measurements from potato varieties grown under different temperature regimes in greenhouse conditions. With the growing impact of climate change on crop production, predictive models as developed here can provide an efficient and cost-effective tool to optimize the control of potato sprouting during storage.2. Zero hunge

Gérer l'après récolte

Les chercheurs se mobilisent pour proposer des solutions de stockage de plus en plus innovantes et durables, capables de gérer de manière optimale les pommes de terre après la récolte. Le défi est de fournir aux consommateurs une marchandise de qualité irréprochable pendant toute l’année. La conférence de l’Association Européenne de Recherche sur la Pomme de terre, section “post-récolte” (“EAPR Post Harvest”) qui s’est déroulée du 29 juin au 1er juillet 2016 à Wageningen aux Pays-Bas, a permis de faire le point sur ces sujets en réunissant plus de 100 participants, chercheurs et industriels, Elle comptait 5 sessions consacrées à des sujets allant de la gestion de la qualité et de la physiologie au contrôle de la germination des pommes de terre après la récolte, en passant par la gestion du stockage. Les différents sujets evoqués lors de la conférence EAPR sont résumés dans cet article destiné à l'interprofession de la pomme de terre

Alternatives au CIPC pour le contrôle de la germination des pommes de terre

This poster describe the different parts of my PhD project and the ongoing research to find alternatives to CIPC for the control of potato sprouting during storage. Those research are conducted at the agronomic research center, Agroscope, in Switzerland and at Gembloux Agro-Bio Tech University in Belgium

Investigating genetic and environmental factors impacting potato dormancy and assessing management strategies to control potato sprouting during storage

Sprouting during potato storage must be controlled as it leads to a decrease in tuber weight, a reduction in nutritional and processing quality, and consequently economic losses. To avoid losses during storage, chlorpropham (CIPC) has been extensively used for decades due to its high efficiency and affordability to mitigate potato sprouting. However, because CIPC and its major metabolite are a potential risk to human health, CIPC has recently been removed from the European market (EU regulation 2019/989). Consequently, the main objective of this thesis was to find economically suitable and sustainable management strategies to control potato sprouting. In this thesis, the influence of year, location and variety factors on potato dormancy was assessed. The analysis was performed using 3,379 records of multi-environment trials collected in Switzerland in five different locations with contrasting environments, over 25 years. In total, 537 genotypes were tested. The potential to predict potato dormancy of 247 predictors (i.e., environmental factors and management during the growing season variables) was evaluated using a forward selection approach to select a model predicting the duration of dormancy. Variety was the most important variable to explain the variability in dormancy (60.3 %), while year and location explained 13.9 % and 5.4 % of the dormancy variability, respectively. The selected predictive model used the variety class and a parameter related to the temperature of the growing season as predictors. The importance of the temperature parameter was confirmed by a greenhouse trial. In order to find alternative anti-sprouting treatments, the potential to control potato sprouting of several synthetic pre- and post-harvest molecules was investigated (i.e., Maleic hydrazide (MH); 1,4-Dimethylnaphtalene (1,4-DMN); 3-decen-2-one and CIPC) and compared to an untreated control. The potential of 1,4-DMN and 3-decen-2-one post-harvest treatments to reinforce the efficacy of MH pre-harvest treatment was also investigated. Residue analyses were performed at the end of the storage. Results showed that all pre- and post-harvest treatments significantly mitigated sprouting for up to seven months of storage. The efficacy of the tested molecules to reduce the sprout weight in comparison to the untreated control was 86.9 %; 77.9 %, 73.6 % and 99.8 % for the MH; 3-decen-2-one, 1,4-DMN and CIPC molecules, respectively. The advantage of the 3-decen-2-one treatment is that it leads to complete necrosis of sprouts within 24 hours after treatment and it can be used as a curative treatment to save potato stocks that have already sprouted. In this study, results showed that there was no benefit to combine pre- and post-harvest treatments to mitigate sprouting. A variety-dependent effect of sprouting and treatment efficacy was observed. In addition, no residue of 1,4-DMN was observed in treated tubers (< LOQ), while residues of both CIPC and MH were found in treated tubers. The efficacy of natural molecules to mitigate sprouting was also evaluated and compared to an untreated control. The tested natural molecules were L-carvone, D-limonene (i.e., mint and orange essential oils, respectively) and ethylene. All the tested molecules efficiently controlled sprouting for up to five months of storage at 8 °C. These natural molecules are advantageous because they are authorized to treat potatoes in organic farming and they can so far be used without a maximum residue limit in the final product. As an alternative or complementary approach, the potential of cold storage (i.e., at 4 °C) to mitigate sprouting after 4.5 months of storage in comparison to storage at a higher temperature (i.e., 8 °C) was evaluated for six processing potato varieties (Lady Claire, Verdi, Kiebitz, Pirol, Agria and Markies). The CIS-ability of these six potato varieties was evaluated by measuring relevant determinant parameters for the industry (e.g., acrylamide content, sucrose content, RS or crisp color quality) after two and/or four months of storage at 4 °C and 8 °C. The potential of reconditioning at 15 °C after a cold storage at 4 °C to decrease total RS, glucose and acrylamide contents in potato tubers was also evaluated. Vacuolar invertase (VInv) gene expression level was measured in tubers stored at 4 °C, at 8 °C and reconditioned at 15 °C. Results showed that a storage at 4 °C efficiently mitigates sprouting in the six tested varieties for up to 4.5 months of storage. Three CIS-resistant varieties were identified (i.e., Lady Claire, Verdi and Kiebitz) and displayed a low total RS and/or glucose content for up to four months of storage at 4 °C. In addition, the reconditioning efficiently reduced the glucose content and the Vinv gene expression in the Markies variety after storage at 4 °C. Several correlations have been observed between glucose or RS content and VInv gene expression. Based on the results obtained in this thesis, several potato management strategies are proposed to mitigate sprouting for different sprouting pressure scenarios

Description of a novel method to calculate the dormancy duration of the potato varieties

The term of dormancy is often used to describe the storability of potato tubers. A dormancy value or duration defines the period potato tubers can be stored before initiating sprouting. Characterization of dormancy value provides useful information to implement strategies for short or long-term storage of potato varieties and can be instrumental to schedule treatment of potato tubers with sprouting inhibitors. The dormancy values of the varieties are provided by breeders and research institutes. Those values can be retrieved from online databases. Comparison of the aforementioned online databases shows that the information is not available for all varieties and that this information can be variable and/or very different for some varieties. The variability can be explained by the heterogeneity of the methods used to determine the dormancy values (e.g. the use of different control varieties and the use of different dormancy scales). The aim of this study is to compare different statistical models based on linear regression analysis that could be used to calculate the dormancy value of a potato variety using field trials data and the corresponding post-harvest observations of tuber sprouting. To perform this comparison, we used dormancy value data collected for 210 potato varieties over 25 years in six locations in Switzerland (Swiss variety testing network datasets). This work provides a comparison of the performances of the different models that are tested and suggests novel methodologies to assess and calculate the dormancy values of the potato varieties

Contrôle de la germination

Fiche technique sur les produits anti-germinatifs rédigée à la demande de l'organisation Suisse Swisspatat, dans le but de communiquer sur les produits anti-germinatifs disponibles sur le marché Suisse ainsi que leurs méthodes d'applications et leurs coûts. Cette fiche est destinée à informer les agriculteurs et l'interprofession et est succeptible d'évouler si de nouveaux produits arrivent sur le marché Suisse. Deux versions ont été distribuées (français et allemand) et sont disponibles en ligne (Fr: http://www.kartoffel.ch/fileadmin/redaktion/pdf/Branche/Merkblaetter/F_controle_germination_sans_prod_no_debord_toprint_final.pdf et All: http://www.kartoffel.ch/uploads/tx_multishop/images/cmsfiles/595109a7a12dc.pdf) et en version papier (Fiches distribuées en Suisse par Swisspatat)