Breeding Differently: Participatory Selection and Scaling Up Innovations in Colombia

Global challenges like sustainable development, climate change, malnutrition and gender inequality can be tackled from an agricultural perspective. Micronutrient deficiency is a major problem for the health and food security of the population. In Colombia, iron deficiencies affect 32% of the children under the age of five; and 43% of the Colombian population have zinc and vitamin A deficiencies. We designed and implemented a research-for-development programme that links agriculture and nutrition through a two-stage project. In the first stage, we selected three new yellow potato cultivars with better nutritional contents, higher yield and better resistance to late blight than the traditional yellow cultivars. We characterized the Colombian germplasm, Solanum tuberosum Group Phureja, for its nutritional attributes. During this stage, studies of the social and nutritional status of the communities were also conducted. In the second stage, we focused on scaling up new potato cultivars to reach potato producers and consumers by promoting the production and marketing of good quality seed potatoes, by establishing four Rural Entrepreneurs Nuclei. The programme promotes gender equity, good dietary habits, the consumption of more nutritious potatoes and empowers local leadership to strengthen governance. Field work was conducted in southern and central regions of Colombia by employing social strategies such as the Family Farming Community Schools. In 50% of the cultivated area, we are replacing the originally used traditional yellow potatoes by the new, more nutritious, potatoes to reach 6 million consumers. A good quality seed system for small-scale potato growers has been implemented. These achievements have been reached through a comprehensive approach in a period of two years.     

Losses during Storage of Potato Varieties in Relation to Weather Conditions during the Vegetation Period and Temperatures during Long-Term Storage

Degradation of harvested tubers due to water loss, sprouting, and disease can cause severe economic difficulties in the cultivation of potatoes (Solanum tuberosum). This study evaluated the storage losses of new varieties of potato and determined the sprouting dates of potatoes stored at different temperatures. Additionally, this study evaluated the influence of weather conditions during the vegetative growth period on the date of sprouting in storage. After storage at three different temperatures (3, 5, and 8 °C), we estimated natural losses and losses caused by sprouting or the development of disease. The potato varieties stored at 3 °C, and 5 °C had similar weight losses (8.8% and 9.3%, respectively), but the potatoes stored at 8 °C had higher losses (10.8%). The average potato losses caused by disease ranged from 0.6% to 10%. The onset of sprouting of potatoes stored at 8 °C depended on the variety and began in the 20 day of December. Storage at 5 °C delayed sprouting by about 50 days compared with storage at 8 °C. Weather conditions (hot and rainy) during vegetative growth of the plants also influenced sprouting date, natural losses, and the amount of disease during storage. Our data showed a significant correlation between the hydrothermal coefficient during the vegetative period and the date of sprouting of potatoes during storage.     

Modification of ELISA by Replacing Incubation of Microtiter Plates in an Incubator with Their Shaking in PVY,PVM and PLRV Detection

ELISA (enzyme-linked immunosorbent assay) is a sensitive and reliable method of plant virus detection. It is commonly used in daily research carried out by scientific institutions and laboratories working on the certification of potato tubers. The key stage in this method is a 3–4-h-long incubation of microtiter plates with IgG and with a conjugate in an incubator at a temperature of 37 °C. The aim of the research was to replace this type of incubation process with a technique of mechanically shaking the plates using a shaker to induce a vibrating movement. Three durations of shaking, performed at room temperature, were adopted: 30, 60 and 90 min with two incubation periods at a temperature of 37 °C: 60 and 180 min which were applied at the stage of coating the IgG plates, following addition of the conjugate. The assessment was made for three dilutions of lyophilized sap from leaf of potatoes (1:10, 1:100, 1:1,000). Replacing the stages of plates incubation with IgG and conjugate at 37 °C with mechanical shaking allowed the whole process of DAS-ELISA to be reduced below 3–4 h without any significant impact on its quality. The process turned out to be equally efficient as the 3-h-long incubation in an incubator for PVY, PVM and PLRV detection by means of DAS ELISA. Applying the 90-min-long incubation on a shaker in comparison to a 3-h-long incubation in an incubator gave comparable or even slightly improved results. The reaction background, i.e. the value of absorbance for sap from healthy plants (negative control) was very low in all the combinations irrespective of the time of reading after the substrate was placed. No significant differences for this parameter were found between the combinations and times of reading. Only in the case of PLRV was a clearly visible decrease in test sensitivity found (no positive reactions) at diluted sap over 1:10. Moreover, it was observed that an increase in dilutions impacted the length of reaction. The dilution 1:10 seemed to be the most favorable (maximum 1:100 for PVY and PVM), wherein the sensitivity and pace of staining the substrate for each of the methods did not provoke any doubts regarding the reliability of the test.     

Sensory Evaluation of Eleven Baked Russet-type Potato Varieties and Clones

Six hundred untrained panelists evaluated the baked sensory appeal of up to six varieties, three clones, and two Russet Norkotah (RN) strains. Panelists consumed small samples of plain baked potato and recorded their preference for aroma, flavor, texture, aftertaste and acceptance. After viewing photographs of two unidentified baked potatoes (RN and Classic Russet) sliced in half, they selected the photo that best described their visual preference of a baked potato; each potato was stored at 6.7 °C for 6 months prior to cooking. Eighty percent of panelists shown the photographs of the unidentified baked potatoes preferred the visual appearance of Classic R (white/cream - colored  flesh) to that of RN (yellow/Gy - colored flesh). Mean scores for all culinary traits averaged > 5.0 on the 1-9 scale, which indicated that panelists generally liked the culinary attributes of all trialed varieties, however, panelists were able to detect differences among varieties. Flavor and texture were addressed in written comments from panelists more frequently than other attributes. On a texture scale of 1–7, with 1 = moist/dense and 7 = dry/crumbly, most panelists preferred baked potatoes with a texture of 3 (creamy/smooth).     

Moisture Content and Oil Uptake in Potatoes (Cultivar Satina) During Deep-Fat Frying

In this study, the effect of ultrasonic sound (at 20- and 40-kHz frequency for 15 min) and drying (at 60 °C for 15 min) pretreatments on the moisture content and oil uptake of potato slices (cultivar Satina) during deep frying were studied. The potato slices were fried at temperatures of 170 and 190 °C for 5, 7 and 10 min. Samples pretreated with ultrasound at 20 kHz had higher moisture contents than those receiving the 40-kHz pretreatment. The highest moisture content was obtained at 20 kHz and frying at 170 °C for 5 min. On the other hand, samples pretreated with ultrasound at 40 kHz had higher effective water diffusivity coefficient and activation energy than those pretreated at 20 kHz. The highest effective water diffusivity coefficient was obtained at 40 kHz and frying at 190 °C for 5 min, whereas the highest activation energy belonged to pretreatment with 40 kHz and frying at 170 °C for 10 min. The range for effective water diffusivity coefficient was 6.95?×?10^?8 to 8.80?×?10^?8 m² s^?1 and that for activation energy was 13.161 to 16.307 kJ mol^?1. In addition, samples pretreated at 40 kHz had a lower oil uptake than those pretreated at 20 kHz. The highest oil uptake took place at 20 kHz, with frying at 170 °C for 10 min. Regression analysis revealed that an exponential model was best for predicting variations in moisture content and oil uptake of potato slices.     

Priming Potato with Thiamin to Control Potato Virus Y

Potato virus Y (PVY) is a major potato pathogen affecting potato yields worldwide. Thiamin, a water-soluble B vitamin (vitamin B₁) has been shown to boost the plant’s immunity, thereby increasing resistance against pathogens. In this study, we tested different concentrations of thiamin (1 mM, 10 mM, 50 mM, 100 mM) and multiple thiamin applications (once, biweekly and monthly) on potato resistance to PVY in Ranger Russet potatoes. Plants were mechanically inoculated with PVY^N:O. This PVY strain is known for causing well-defined foliar symptoms. We collected leaflets weekly through April and May 2015 and tested them with an enzyme-linked immunosorbent assay specific to PVY as well as by real time quantitative RT-PCR. These assays allowed us to determine the presence and level of PVY in different parts of the plants. We found that the highest thiamin concentration treatment (100 mM) produced the lowest virus level in potatoes across all dates and leaflet samples. Also, it was found that multiple applications of thiamin had a positive effect on reducing virus level, especially when thiamin was applied every four weeks.     

Effect of Thermal Processing on Potato Sensory Profile and off-Odours Detection during Storage

One of the most used thermal treatments in potatoes to inactivate enzymes and prevent their oxidation is the boiling process. This treatment significantly decreases the taste of the potato and causes “off-odours” during storage, whatsoever, represents a big problem for the production of potato-based foodstuffs. This study focused on evaluating the sensory profile of potato slices subjected to a boiling process of three Mexican potato varieties (Alpha, Chica and Gallo) and on off-odours detection in potato produced during storage. According to the examined parameters through PanelCheck, the trained panel had a good performance, resulting 8 of the 12 attributes evaluated were significant. The formation of “cardboard-like off-odour” was detected in the Alpha and Chica varieties at the 24 and 33 h of storage, respectively. Chica potato presented this off-odours with at level significantly lower than Alpha potato (about 30% lower). With respect of Gallo variety, this presented different oxidation olfactory perceptions described by the assessors as “burnt note”, detected after 5 h of refrigerated storage. An adequate election of the variety of potato according to processing will allow an effective utilization of this vegetable and the obtention of potato-based foodstuffs much more stable.     

Report on the Workshop “Research Challenges for the Seed Potato Sector”

Held on July 2017 during the 20^th EAPR Conference in Versailles, France, the workshop intended (1) to review—and exchange with participants—some recent advances and concerns for the seed potato sector (new regulations, seed health, multiplication schemes including true potato seed, seed crop management, etc.) and (2) to define the main challenges for future research and improvement for seed potatoes production and regulation systems to secure the whole chain of potato production.     

Analysis of <Emphasis Type="Italic">Potato Mop-Top Virus</Emphasis> Survival Probability in Post-Harvest Storage

Potato mop top virus (PMTV) induced necrosis can cause tuber quality loss at harvest and storage. Stored potatoes help maintain a constant supply of potatoes to the market and processing industry. PMTV-induced necrosis continues to develop during storage and appropriate timelines are needed for growers to make marketing decisions of their potatoes before incurring any significant quality losses. Survival analysis was used to estimate the time to event occurrence (PMTV-induced necrosis) in four (red-, russet-, white-, and yellow-skinned) potato market types across six post-harvest assessments conducted over two years. At each assessment the presence and absence of PMTV-induced necrosis was recorded and probability of tuber survival was estimated. Survival curves were significantly different among the four market type potato cultivars (Log-Rank test, P < 0.0005). Red- and russet-market type cultivars showed low and high survival probability, respectively, demonstrating that red cultivars need priority marketing. The survival probabilities decreased with increased storage time during both years, indicating that PMTV-induced necrosis development is dependent on potato cultivar and post-harvest storage. The median (50% of tubers with symptoms) survival times were estimated as 167 and 214 days for red- and other market type potato cultivars. The information from this study could potentially help growers regulate storage times for their cultivars to minimize tuber quality loss due to PMTV-induced tuber necrosis.     

Aminopyralid Residue Impacts on Potatoes and Weeds

Aminopyralid is used in Alaska to control certain invasive weed species; however it appears to have an extended soil half-life in interior Alaska resulting in carry-over injury in potatoes. Field studies at three experiment stations in Delta Junction, Fairbanks, and Palmer, Alaska were established to determine the dose–response of weeds and above and below ground potato growth to soil-applied aminopyralid (0, 8, 15, 31, 62, and 123 g ae ha^?1) . Both prostrate knotweed and narrowleaf hawksbeard were susceptible to aminopyralid. At Delta Junction and Fairbanks, visual injury of potatoes greater than 25 % was observed at 15 g ae ha^?1 aminopyralid, whereas at Palmer visual injury was greater than 40 % at 8 g ae ha^?1, the lowest rate tested. Potato tuber production was reduced by aminopyralid at rates of 15 g ae ha^?1 and above at both Delta Junction and Palmer. Sub-samples of potato tubers from Delta Junction and Palmer were analyzed for aminopyralid content and grown out to determine if aminopyralid in tubers would reduce subsequent growth. The aminopyralid concentration in potato tubers increased with increasing field application rates, with 30 ppb extracted from tubers grown at the highest application rate (123 g ae ha^?1). All plants grown from daughter tubers except from control plots in Palmer exhibited injury symptoms. The number of emerged shoots, and shoot height decreased with increasing aminopyralid concentrations in the tuber, with injury rates greater than 70 % at 8 g ae ha^?1.     

Design, Construction, and Testing of an Automated NIR In-line Analysis System for Potatoes. Part II. Development and Testing of the Automated Semi-industrial System with In-line NIR for the Characterization of Potatoes

An automated semi-industrial system with in-line near-infrared reflectance (NIR) for the characterization of the chemical composition of potatoes was designed and constructed, and its performance was tested. The system consisted of the following subsystems: sample crate manipulator, weighing unit for the gross sample weight, potato washing machines with a washing water recycling system, belt for visual inspection of the potatoes, unit for measuring the underwater weight (UWW), industrial rotary saw blade rasp for pulping the potatoes equipped with a sulfite dosage system for inhibiting enzymatic browning of the pulped potatoes, and industrial NIR system for the measurement of the potato composition. The whole system was controlled and operated by a programmable logic controller and process personal computer system. The system was able to process 12 potato samples per hour. Measurements were done to establish the sample carry-over in the system. The carry-over was proven to be well below the maximum acceptable level of 2%. The UWW values established with the automatic system corresponded very well with the UWW data obtained by manual weighting. The day-to-day reproducibility of the UWW system was tested with golf balls. These balls have about the same specific gravity and size as potatoes. The day-to-day reproducibility coefficient of variation of the UWW unit was 0.4%. As a principle of proof, two tentative partial least squares calibration models, one for the starch concentration and one for the coagulating protein concentration in the potato samples, were calculated, applying leaving one out cross-validation. Both models were very promising. The by NIR-predicted starch concentrations showed to be at least as good or even better than the by UWW-obtained starch concentrations. The average difference between the by NIR-predicted and the chemically measured starch concentration was 0.0 ± 0.3% (w/w). For the coagulating protein concentration, the average difference between the by NIR-predicted and the chemically measured concentration was 0.00 ± 0.06% (w/w). In future years, potatoes of a wider range of varieties, growing locations, and growing seasons have to be added to the present tentative model, in order to get a robust NIR model.     

整薯播种对马铃薯生育及产量的影响

1979～1984年,在黑龙江省北部黑土地区气象条件、生产水平和栽培条件下,通过田间试验,研究了整薯播种对马铃薯生育和产量的影响。结果表明:整薯播种与传统习惯的切块播种相比,6年期间平产出现频率为2次,一般年份整薯播种比切块播种增产9～12%,在春旱严重的1980年,整薯播种表现出非常突出的抗旱保苗效果。在群体叶面积发展进程上,整薯播种表现早发早衰,切块播种晚发晚表,一般年份光合势前者比后者高9.6%,春旱严重的1980年高82.8%。块茎商品率以112.5克为准时,6年平均整薯播种为74.1%,切块播种为80.0%,两者相差5.9%;以50克为准时,整薯播种为97.3%,切块播种为98.2%,两者相差0.9%。     

Sorghum extrusion process combined with biofortified sweet potato contributed for high iron bioavailability in Wistar rats

This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n = 7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES + SP group showed higher (p < 0.05) expression of DcytB, ferroportin and hephaestin when compared to the control group. The DS group showed high (p < 0.05) expression of DMT-1 and the ES showed high mRNA expression of transferrin and ferritin. The changes in the sorghum physicochemical properties from extrusion process reduced the iron and phytate content, and increased the gene expression of proteins involved in iron metabolism, improving iron bioavailability. The combination of sweet potato and sorghum flour (dry or extruded) improved the iron capture and total antioxidant capacity, probably due to the presence of β-carotene and antioxidant compounds.     

Effect of the ring rot pathogen and latent potato viruses on ring rot symptoms and yield of potatoes

The ring rot bacterium,Corynebacterium sepedonicum (Spieck. and Kotth.) Skapt. and Burkh., and latent potato viruses (potato virus S and potato virus X) were investigated for their effect on ring rot symptom development on potato plants in the greenhouse and on symptom development and yield of potatoes in the field. Both virus-free (VF) and virus-infected (VI) Red Pontiac stem cuttings root-inoculated with ring rot bacteria in the greenhouse developed typical (T) ring rot symptoms, and symptom severity did not differ between VF and VI plants. In a field study, both VF and VI Russet Burbank seed pieces knife-inoculated with ring rot bacteria produced plants with atypical (A) and T ring rot symptoms as well as a combination of both types. The data suggest that more A than T symptoms develop on VI plants and more T than A symptoms develop on VF plants. Combined infection with the ring rot pathogen and the latent potato viruses resulted in greater yield losses of total and marketable Russet Burbank tubers than infection with the bacterial or viral pathogens alone.     

In vitro Bioaccessibility of Lutein and Zeaxanthin of Yellow Fleshed Boiled Potatoes

Yellow fleshed potatoes contain significant amounts of lutein and zeaxanthin but the bioaccessibility of potato carotenoids has not yet been investigated. The purpose of this study was to estimate the in vitro bioaccessibility of carotenoids provided by potato. Lutein and zeaxanthin concentrations of boiled, freeze dried and milled samples of seven yellow fleshed potato accessions were determined by HPLC before and after different steps (gastric, duodenal and micellar phase) of in vitro digestion. The gastric and duodenal digestive stability of lutein and zeaxanthin in boiled tubers of the different accessions ranged from 70 to 95 % while the efficiency of micellarization ranged from 33 to 71 % for lutein and from 51 to 71 % for zeaxanthin. For all accessions, amounts of lutein and zeaxanthin after micellarization were significantly lower than the original amount found in the boiled samples. The accession 701862 showed the highest bioaccessible lutein concentration (280 μg/100 g, FW) and the accessions 703566 and 704218 showed the highest bioaccessible zeaxanthin concentration (above 600 μg/100 g, FW). Considering the mean potato intake in the Andes (500 g per day), the accession 701862 provides 14 % of the lutein intake suggested for health benefits and the accessions 703566 and 704218 provide 50 % more than the suggested zeaxanthin intake.     

Conversion of Potato Starch and Peel Waste to High Value Nanocrystals

The present study aimed to convert starch and potato peel waste to nanocrystals. Starch nanocrystals were prepared using two methodologies: direct acid hydrolysis and enzyme pretreatment followed by acid hydrolysis. Direct hydrolysis broke down the starch granules to nanocrystals in 12 days. Enzyme pretreatment with starch hydrolytic enzymes (α-amylase and amyloglucosidase) reduced the time for preparation of starch nanocrystals by 6 days. Starch nanocrystals of optimum size were obtained with both the treatments and the resultant size ranged from 10 to 50 nm. Nanocrystals were disk-like platelets in appearance. Cellulose nanocrystals were derived from cellulosic material in the potato peel. Cellulose was isolated from peel waste with alkali treatment. Further, cellulose nanocrystals from potato peel and cellulose microcrystalline were prepared by acid hydrolysis. Microscopic images revealed that the aqueous suspension of cellulose nanocrystals derived from potato peel were single rod shaped, whereas those derived from cellulose microcrystalline were rod-like nanoparticles, agglomerated in the form of bundles including some of the rods in single units (well separated). The size of potato peel nanocrystals ranged from 40 to 100 nm (length) and cellulose microcrystalline ranged from 4 to 20 nm (diameter) by 110 to 250, given 4 to 20 nm (length), respectively. As starch nanocrystals as well as cellulose nanocrystals are derived from biopolymer, both can be considered safe for humans and the environment. Moreover, the biodegradable nature of these nanocrystals makes them superior over metallic nanoparticles, particularly in the field of nanocomposites.     

Gene Flow between Potato Cultivars under Experimental Field Conditions in Argentina

Wild and cultivated potatoes form a polyploid series with 2n = 2x to 2n = 6x (x =?12). In nature, they are separated by external and/or internal hybridization barriers that, when incomplete, provide opportunities for gene flow and introgression. Isolation distances estimated in one environment are not necessary extrapolable. As a starting point for pollen-mediated gene flow risk assessment in potatoes, an experiment was set up in the field in one of the major potato growing area in Argentina, with two pollen-pistil compatible tetraploid commercial cultivars with differential molecular marker patterns. The field design consisted of a 10?×?10 m central square with the pollen donor, surrounded by circles with a male sterile pollen recipient, set every 10 m up to 40 m. The crop was managed as a perennial, and data were recorded over 2 years. Seeded berries were obtained in both years at 30 and 40 m away from the center; all of them contained hybrid seeds as revealed by electrophoretic profiles. We consider that a minimal required isolation distance of 100 m or more would be more suitable for preventing undesirable gene flow in the area.     

A bioassay with excised potato shoot-tips for assessing the effect of growth-inhibiting volatile compounds in the potato

Summary A bioassay technique is described for assessing growth-regulatory activities of volatile compounds in the potato. Excised potato shoot-tips (3 mm) were cultured aseptically in an aqueous medium in the dark at 25°C. After 7–12 days in culture, growth rates were measured by the increase in length of the treated shoot-tips. The addition of low concentrations (1 μmol/l) of gibberellic acid (GA₃) and kinetin to the culture medium enhanced shoot growth. Known sprout suppressants inhibited growth of shoots in the bioassay. Of those tested 1,4-dimethylnaphthalene was found to be the most potent. The effectiveness of these known suppressants of sprout growth of whole potato tubers in inhibiting growth in the bioassay is presented as evidence of the validity of using this bioassay to detect unknown growth inhibitory volatile compounds evolved by stored potatoes.     

UV-C处理对甘薯贮藏品质的影响

以海南桥头产区的“高系14”甘薯为材料,分别进行10、20、30 min的UV-C照射处理,统计甘薯贮藏60 d内的腐烂率、失重率和发芽率,并同时记录5种生理指标的变化,以探讨UV-C处理对甘薯贮藏品质的影响。结果表明：UV-C处理显著降低了甘薯贮藏期间的腐烂率,但同时促进了发芽,而对失重率无显著影响。生理指标方面,30 min的UV-C照射提高了可溶性蛋白的积累,减少可溶性固形物的损耗,并促进了POD、SOD和CAT的总体酶活性。综合来说,UV-C处理若要应用于甘薯贮藏保鲜,还需辅助使用其他的抑芽手段。     

QTL Analysis of Late Blight Resistance in a Diploid Potato Family of Solanum spegazzinii × S. chacoense

Several quantitative trait loci (QTL) for resistance to late blight have been reported in diploid potatoes. The diploid wild potato species Solanum chacoense possesses a high degree of horizontal resistance to late blight. In the present study, we report on QTL mapping for late blight resistance in a diploid mapping population of 126 F₁ of Solanum spegazzinii (susceptible) × S. chacoense (resistant). The area under the disease progress curve (AUDPC) values for late blight resistance using the “whole plant in vitro assay” and the “detached leaf assay” on the mapping population displayed quantitative variation. Out of 64 AFLP primer-pairs combinations and SSR markers, a total of 209 significant AFLP loci were placed onto the 12 linkage group of potato covering a total map length of 6548.1 cM. QTL analysis based on the AUDPC dataset of the “whole plant in vitro assay” using the interval-mapping option identified two QTL (LOD?>?2.5) located on linkage groups IX and X, which explained 14.70 and 3.40% variation, respectively. The present study revealed the presence of potential new genetic loci in the diploid potato family contributing to quantitative resistance against late blight.