Breeding Late Blight Resistant Potatoes for Organic Farming—a Collaborative Model of Participatory Plant Breeding: the Bioimpuls Project

In organic potato production, the need for varieties with durable late blight resistance developed through classical breeding programmes is urgent. Besides late blight resistance, other variety characteristics needed in organic potato production are early canopy closure for weed suppression and good tuber dormancy to eliminate the need for (chemical) sprouting inhibition during storage, amongst others. This paper is a unique example of collaboration between researchers, farmers and professional breeders of both large, medium and small breeding companies. The aim of the resulting breeding project, Bioimpuls, was to provide a substantial impulse to both the organic and conventional potato breeding sector by enlarging the access to various sources of late blight resistance. The Bioimpuls activities include providing true seed populations for variety selection with five available sources of R-genes against Phytophthora infestans, early and advanced introgression breeding with six new R-genes, and education and communication. The results achieved over the 11-year period (2009–2019) are analysed. Many true seed populations containing multiple resistance genes are produced and selected, and a constant flow of breeding clones is entering the evaluation and positioning trials of companies. However, it will still take a considerable amount of time before varieties with stacked resistance genes will replace the new resistant single gene varieties entering the market in the next few years. Five out of six new sources of R-genes need more years of backcrossing before they are ready for commercial use. Bioimpuls successfully introduced a training course for farmer breeders, and published a manual for potato breeding.

Co-Inoculation of Organic Potato with Fungi and Bacteria at High Disease Severity of Rhizoctonia solani and Streptomyces spp. Increases Beneficial Effects

Rhizobacteria-based technologies may constitute a viable option for biological fertilization and crop protection. The effects of two microbial inoculants (1) PPS: Pseudomonas protegens, P. jessenii and Stenotrophomonas maltophilia biocontrol bacterium strains and (2) TPB: Trichoderma atroviride, Pseudomonas putida, and Bacillus subtilis fungi, bacteria biocontrol, and biofertilizer combinations were examined on potato (Solanum tuberosum L. var. Demon) in three consecutive years in irrigated organic conditions. The number of tubers showing symptoms of Streptomyces sp. and Rhizoctonia sp. was recorded. The severity of symptoms was evaluated based on the damaged tuber surface. There was a large annual variability in both the symptoms caused by soil-borne pathogens, and the effect of bio-inoculants. In the first and second year, with a stronger Rhizoctonia and Streptomyces spp. incidence, the bacterial and fungal combination of TPB inoculums with both the potential plant nutrition and biocontrol ability of the strains seemed to have a better efficiency to control the diseases. This tendency was not supported in the third year, and this may be attributed to the relatively high natural precipitation. Further studies are required to investigate the agronomic benefits of these inoculants and to tailor their application to the soil microbial characteristics and weather conditions.

Productivity and profitability of organic and conventional potato (Solanum tuberosum L.) production in West-Central Bhutan

Bhutan aspires to be an entirely organic nation. Food self-sufficiency and increasing farm household income are critical priorities in the country. Realising these priorities necessitates assessing the country’s current organic agriculture performance. The objectives of this study were to investigate the productivity and profitability of organic and conventional potato and farmers’ constraints in producing organic potato in West-Central Bhutan. Multistage and purposive sampling techniques were used to select the study sample. A semi-structured questionnaire and face-to-face interviews were employed to gather primary data for the 2019 cropping cycle from 93 potato farmers: 43 organic farmers in the Gasa District and 50 conventional farmers in Wangdue Phodrang District. Descriptive statistics, cost and return analysis, and independent sample t-test were applied for data analysis. The results revealed that the conventional potato’s productivity (tuber yield) and profitability were significantly higher (p < 0.001) than organic potatoes. The average productivities for organic and conventional potatoes were 7.48 and 19.22 t/ha, respectively. Organic potato farmers incurred a loss of −202,708.47 Ngultrum (Nu)/ha, while conventional potato farmers incurred a profit of 83,832.85 Nu/ha. The benefit-cost ratios of organic and conventional potato stood at 0.40 and 1.27, respectively. Lack of premium price, pest and disease problems, low crop productivity, and climate change were the constraints faced by organic potato farmers. The study found that the productivity and profitability of the conventional potatoes were higher than the organic potatoes in West-Central Bhutan in the current scenario. Further, the critical information will contribute to guiding Bhutan’s vision for its organic agriculture development.

Research of midseason potato varieties suitable for organic growing

An essential issue in organic potato production is choosing the right varieties, because varieties grown under conventional conditions may not always be suitable for organic production. The choice of variety was based solely on farmers’ experience, as research results were not available. Because of the lack of reliable information, ÖMKi initiated an on-farm research program for organic potato production in 2012. 13 mid-season potato varieties with certain degree of resistance to relevant diseases or abiotic stresses were tested on 22 organic farms (2012-2015) in close cooperation with the growers. Quantitative and qualitative parameters were assessed at harvest. The average yield was 2.19-3.45 kg/m² (21-34 t/ha). Among seven qualitative parameters the most relevant quality problems were: Streptomyces and Rhizoctonia infection and damage by insect pests. No significant differences could be shown among the varieties regarding the assessed parameters, but disease resistance often differed compared to the descriptions provided by the seed tuber distributors. Besides summarizing and sharing research results, regular meetings and field trips were arranged for farmers. As an indirect result of the on-farm research program the communication was highly improved among the participants and a well-working organic potato workgroup was formed.

Potato Peels as a Source of Novel Green Extracts Suitable as Antioxidant Additives for Fresh-Cut Fruits

Potato is a source of different bioactive compounds, and the potato transformation industry produces conspicuous quantities of potato peels as waste. In this context, the objective of this research was twofold: (i) the evaluation of the recovery of bioactive compounds from organic potato byproducts through an innovative multistep green extraction process; (ii) to evaluate the preservation during storage of the main quality-physicochemical parameters of minimally processed apples treated with two different natural extracts obtained. The potato extracts were obtained by solid CO2 cryomaceration followed by solid/liquid extraction based on water or 10% ethanol/water solutions. The efficacy of potato extracts, with or without 1% of citric acid, was tested in comparison with traditional preserving compounds in minimally processed apple preparation. All the extracts were characterized by a high antioxidant power and were rich in phenol compounds, showing a good activity in keeping the qualitative parameters of fresh-cut apple. A significant anti-browning effect as well as a slowing down of the softening of fruits during storage were observed. The obtained results suggest the suitability of the potato extracts as antioxidant additives for fresh-cut fruits, thus avoiding the use of unsafe chemicals.