Background Conventional strawberry production in Europe relies on chemical soil fumigation to mitigate the negative effects of soilborne pathogens prevalent in production areas such as Huelva (Spain). Considering the restrictions imposed by European policies on the use of chemicals, the adoption of alternative non-chemically disinfected cropping systems has become an efficient way. Objective To ascertain the effectiveness of non-chemically disinfected cropping systems compared to conventional system. Methods Yield and fruit quality of six strawberry cultivars were evaluated under two cropping systems: non-chemically disinfected cropping systems by solarization, organic and soilless compared with conventional system currently used in Huelva. Results The cultivation system and the cultivars influenced variations in yield (early and total fruit production and plant size) and fruit quality (firmness, soluble solids content and acidity) variables. All cultivars performed better in the conventional system. In biosolarized, organic and soilless systems, yield was lower than in conventional system. Biosolarization was the most suitable system for achieving acceptable yields and quality fruit for most strawberry cultivars which were used in this investigation. Conclusions The results showed that all the four cultivation systems still need be optimized and there is some room for further improvement; in this sense, the soilless system could be a promising alternative in the near future in Huelva. In general, ‘Rociera’ and ‘Primavera’ showed the highest average yield per plant, while ‘Calinda’ stood out for its organoleptic fruit quality, underscoring the importance of cultivar choice for achieving high production and quality.

Strawberry(Fragaria×ananassa)fruits are an excellent source of L-ascorbic acid(AsA),a powerful antioxidant for plants and humans.Identifying the genetic components underlying AsA accumulation is crucial for enhancing strawberry nutritional quality.Here,we unravel the genetic architecture of AsA accumulation using an F1 population derived from parental lines'Candonga'and'Senga Sengana',adapted to distinct Southern and Northern European areas.To account for environmental effects,the F1 and parental lines were grown and phenotyped in five locations across Europe(France,Germany,Italy,Poland and Spain).Fruit AsA content displayed normal distribution typical of quantitative traits and ranged five-fold,with significant differences among genotypes and environments.AsA content in each country and the average in all of them was used in combination with 6,974 markers for quantitative trait locus(QTL)analysis.Environmentally stable QTLs for AsA content were detected in linkage group(LG)3A,LG 5A,LG 5B,LG 6B and LG 7C.Candidate genes were identified within stable QTL intervals and expression analysis in lines with contrasting AsA content suggested that GDP-L-Galactose Phosphorylase FaGGP(3A),and the chloroplast-located AsA transporter gene FaPHT4;4(7C)might be the underlying genetic factors for QTLs on LG 3A and 7C,respectively.We show that recessive alleles of FaGGP(3A)inherited from both parental lines increase fruit AsA content.Furthermore,expression of FaGGP(3A)was two-fold higher in lines with high AsA.Markers here identified represent a useful resource for efficient selection of new strawberry cultivars with increased AsA content.

Microbial interactions in agricultural soils can play important roles in the control of soil-borne phytopathogenic diseases. Yields from blueberry plantations from southern Spain have been impacted by the pathogenic fungus, Macrophomina phaseolina. The use of chemical fungicides has been the common method for preventing fungal infections, but due to their high environmental impact, legislation is increasingly restricting its use. Biocontrol alternatives based on the use of microorganisms is becoming increasingly important. Using the metabarcoding technique, fungi and bacteria were characterized (via 16S and ITS regions, respectively) from rhizosphere soils of healthy and dead blueberry plants infected by M. phaseolina, and which had undergone three different treatments: two biocontrol strategies—one of them a mix of Pseudomonas aeruginosa and Bacillus velezensis and the other one with Bacillus amyloliquefaciens—and a third treatment consisting of the application of a nutrient solution. The treatments produced changes in the bacterial microbiota and, to a lesser extent, in the fungi. The abundance of Fusarium was correlated with dead plants, likely favoring the infection by M. phaseolina. The presence of other microorganisms in the soil, such as the fungi Archaeorhizomyces or the bacteria Actinospica, were correlated with healthy plants and could promote their survival. The different genera detected between dead and healthy plants opens the possibility of studying new targets that can act against infection and identify potential microorganisms that can be used in biocontrol strategies.

Irrigation sustainability is particularly important in the vicinity of Doñana National Park (Huelva, Spain), where Europe’s most important wetland area coexists with a profitable strawberry irrigation activity. In this paper, an innovation and technology transfer project was laid out. The project was promoted by the Institute of Agricultural and Fisheries Research and Training (IFAPA), belonging to the Regional Government of Andalusia. The main objective of the project was to contribute to the sustainability of the complex ecological, productive, and social system of this region. The project was focused on the rational use of water resources. Experimentation, demonstration, technology transfer, and training activities were carried out, involving public administrations, companies, and private farms. The project was carried out in collaboration with strawberry companies covering a total surface area of 1900 hectares. Irrigation application efficiency and irrigation water productivity increased by 66% and there was also a significant increase in water saving (44%), without resulting production losses. The success of the activity was based on the implication of farmers in experimentation assignments. During a five-year time span, irrigation trials took place on several farms. This fact allowed a progressive improvement of irrigation management by farmers based on confidence in the experimental work results.

(1) Background: Strawberry cultivation is highly dependent on soil disinfestation for proper development. Since the definitive methyl bromide phase-out, other chemicals have been used as alternatives. This research provides an overview on the efficacies of soil disinfestation methods on controlling soil fungal diseases of strawberry. (2) Methods: The efficacy of several soil disinfestation methods on soil fungal pathogens (SFP: Fusarium spp. and Macrophomina phaseolina) was analyzed in experimental field trials during eleven growing seasons. (3) Results: Average efficiencies in reducing soil pathogen inocula for soil disinfestation techniques are given. Soil disinfestations with chloropicrin, allyl isothiocyanate, dazomet, 1,3-dichloropropene:chloropicrin, methyl iodide:chloropicrin, and dimethyl disulfide reduced Fusarium spp. and M. phaseolina soil inocula by more than 90%. Combination of solarization with organic manures (biosolarization) reduced Fusarium spp. soil populations by 80% and M. phaseolina by 79%. Reductions in plant mortality and increases in fruit yields over the untreated controls did not differ between chemically fumigated and biosolarized plots. (4) Conclusions: Soil fungal pathogens are effectively controlled by chemical fumigation of soils in intensive strawberry crops in Spain. In the case of mixed infestations of SFP with nematodes, the most efficient treatment in suppressing soil-borne diseases was soil fumigation with 1,3-dichloropropene:chloropicrin, but other alternative chemicals, such as allyl isothiocyanate, dazomet, and dimethyl disulfide, provided high efficacies in reducing the SFP inocula. Soil biosolarization is proposed as an effective alternative to chemical soil fumigation for strawberry cultivation in Southern Spain when SFP inocula is not remarkably high.

The effect of antagonistic bacteria to control Macrophomina phaseolina was evaluated under in vitro, growth chamber, greenhouse and field conditions. A total of 177 bacteria, isolated from Athrocaulon macrostachyum rhizosphere of the Lebrija marsh, were screened for their potential against M. phaseolina (causes charcoal rot in strawberry) by dual culture assay. Of these isolates, 14 most promising strains were molecularly identified by the 16S rDNA sequencing method using the EzBioCloud database. These strains were tested for in vitro hydrolytic enzymes, HCN production, and biocontrol against M. phaseolina in strawberry plants. All the 14 strains produced, at least, one hydrolytic enzymatic activity and one of them, which belongs to Brevibacterium genus (Hvs8), showed the lowest records of disease incidence (20%) and severity (0.4). With these results, greenhouse and field trials were carried out with the Hvs8 strain, compared to non-treated control. In the greenhouse assays, Hvs8 strain increased root dry mass by 30%, over the control. In the field trials, production and fruit quality were not significantly different between Hvs8 treatment and non-treated control, but plant mortality and plant mortality associated to M. phaseolina decreased by more than 24% and 65% respectively, in Hvs8 treatment. This study suggests that Brevibacterium sp. Hvs8 strain could be a candidate for controlling charcoal rot in strawberry.

Strawberry (Fragaria×ananassa Duch.) production requires the input of large amounts of water provided by irrigation during the entire production cycle. However, water availability is shrinking in many important strawberry cropping areas, such as Huelva (in Europe), compromising the environmental sustainability and economic viability of strawberry production. Besides technical approaches, water-saving strategies are necessary for improving strawberry water productivity such as the use of low water-consumptive cultivars with high productivity or cultivars allowing deficit irrigation (DI) strategies. A two-year field experiment was conducted to compare the physiological and agronomical response of six commercial strawberry cultivars (‘Sabrina’, ‘Fortuna’, ‘Splendor’, ‘Primoris’, ‘Rabida’ and ‘Rociera’) to six different water treatments ranging from 65% to 140% of estimated ‘Sabrina’ evapotranspiration (ETcSab; ~224–510 mm year−1). Cultivars differed substantially in yield and water consumption linked to their biomass partitioning into reproductive/ vegetative organs, determining different yield efficiency (YE). Their water needs (IN) conditioned their response to different water supplies, involving significant yield losses in DI treatments (<20% IN) but not decreasing fruit quality. The highly-consumptive and productive ‘Rabida’ and ‘Rociera’, reduced yields by DI (<40%) but were still profitable; the low-water-consumptive but still productive ‘Fortuna’, ‘Splendor’ and ‘Primoris’ represent significant water-savings (<20%) in strawberry cultivation.

Strawberry fruit quality traits can be affected by genotype–environment interactions, determining the final consumer acceptance of fruits. Trait stability under varying environments is necessary to ensure the fruit quality of strawberries selected by breeding programs. Hence, inter- and intra-annual variation of organoleptic and functional fruit quality parameters of five strawberry varieties throughout four consecutive cropping seasons was analyzed to assess their relative stability. In most varieties, organoleptic parameters showed higher inter-annual stability but greater variability throughout the season, while the reverse was true for the functional quality parameters. Relative humidity and mean and minimum temperatures partially accounted for fruit quality variation but other factors along with the genotype may also have an influence. Among the varieties, ‘Splendor’ displayed greater year-on-year stability in organoleptic parameters, and ‘Sabrina’ and Candonga® showed higher inter- and intra-annual stability on functional fruit quality, respectively. Environmental variation did not affect fruit quality parameters similarly in all strawberry varieties. In ‘Sabrina’ and Candonga® antioxidant capacity (TEAC) was greater and stable throughout the cropping season, underlining TEAC as a tool for varietal selection, and suggesting these two varieties as parents for breeding programs that seek healthy features and high-quality fruits that meet consumer demands.

(1) Background: Spain is the sixth strawberry producer in the world, with about 6500 ha producing more than 350,000 tons, and an annual commercial value about 390 million €. Stunted and dead strawberry plants are frequently associated with plant-parasitic nematodes, but nematode diseases have not been characterized to date in the country. (2) Methods: A poll on the perception of the impact of nematodes on strawberry production was carried out by face-to-face interviews with farm advisors. In addition, nematological field surveys were carried out at the end of the growing season in 2017 and 2018 to determine prevalence and abundance of plant-parasitic nematodes in strawberry crops. The host suitability to Meloidogyne hapla of seventeen strawberry cultivars and the tolerance limit to M. hapla at progressively higher initial population densities (Pi) were assessed in pot experiments in a growth chamber. Comparison of the relative efficacies of several soil disinfestation methods in controlling nematode populations (M. hapla and Pratylenchus penetrans) was carried out in experimental field trials for twelve consecutive years. (3) Results: Meloidogyne spp., Pratylenchus penetrans, and Hemicycliophora spp. were the main plant-parasitic nematodes in the strawberry fields in South Spain. Root-knot nematodes were found in 90% of the fields, being M. hapla the most prevalent species (71% of the fields). A tolerance limit of 0.2 M. hapla juveniles per g of soil was estimated for strawberry, and currently cropped strawberry cultivars did not show resistance to M. hapla. Nematode population densities were reduced by more than 70% by soil fumigation with 1,3-dichloropropene, dazomet, dimethyl-disulfide, and methyl iodide. The efficacy of metam-sodium in reducing nematode populations was about 50% and that of chloropicrin, furfural, and sodium-azide, less than 40%. Combination of solarization with organic manures (biosolarization) reduced soil nematode populations by 68–73%. (4) Conclusions: Plant-parasitic nematodes (Meloidogyne, Pratylenchus, and Hemicycliophora) are widely distributed in the strawberry fields of Southern Spain. Strawberry is a poor host for M. hapla with a tolerance limit of 0.2 J2 per g of soil, and low population increases in cropping cycles of 7–8 months. Strawberry cultivars show a range of susceptibility and tolerance to M. hapla, but no resistance is found. Nematodes are effectively controlled by chemical fumigation of soils, but soil biosolarization is equally effective, and therefore, can be proposed as a sustainable alternative for pathogen control in strawberry cultivation.

Improvement of nutritional and organoleptic quality of fruits is a key goal in current strawberry breeding programs. The ratio of sugars to acids is a determinant factor contributing to fruit liking, although different sugars and acids contribute in varying degrees to this complex trait. A segregating F1 population of 95 individuals, previously characterized for several fruit quality characters, was used to map during 2 years quantitative trait loci (QTL) for 50 primary metabolites, l-ascorbic acid (L-AA) and other related traits such as soluble solid content (SSC), titratable acidity (TA), and pH. A total of 133 mQTL were detected above the established thresholds for 44 traits. Only 12.9% of QTL were detected in the 2 years, suggesting a large environmental influence on primary metabolite content. An objective of this study was the identification of key metabolites that were associated to the overall variation in SSC and acidity. As it was observed in previous studies, a number of QTL controlling several metabolites and traits were co-located in homoeology group V (HG V). mQTL controlling a large variance in raffinose, sucrose, succinic acid, and L-AA were detected in approximate the same chromosomal regions of different homoeologous linkage groups belonging to HG V. Candidate genes for selected mQTL are proposed based on their co-localization, on the predicted function, and their differential gene expression among contrasting F1 progeny lines. RNA-seq analysis from progeny lines contrasting in L-AA content detected 826 differentially expressed genes and identified Mannose-6-phosphate isomerase, FaM6PI1, as a candidate gene contributing to natural variation in ascorbic acid in strawberry fruit.

Maria T. Ariza, Juan J. Medina, Luis Miranda, Jos e A. G omez-Mora, Berta De Los Santos, Antonieta de Cal, Elsa Martínez-Ferri, Lucía Cervantes, Rosalía Villalba, and Carmen Soria Instituto Andaluz de Investigaci on y Formaci on Agraria y Pesquera (IFAPA), Consejería de Agricultura, Pesca y Desarrollo Rural, Junta de Andalucía, Edificio Administrativo Bermejales, Avda. de Grecia s/n, 41012, Sevilla

A new TaqMan real-time polymerase chain reaction (qPCR) was developed to accurately detect and quantify the soil-borne fungus Fusarium solani, pathogen to strawberry, in plant and soil samples. The assay was designed using sequences from the translation elongation factor 1 alpha (EF-l alpha) gene. The assay is highly specific: it specifically detected F. solani isolates when tested against 95 fungal isolates from 27 different species. The detection limit of the assay was 50 fg for F. solani genomic DNA and 10(2) conidia/g soil. A significant correlation (P = 0.0002) was observed between the amount of genomic DNA of F. solani detected by qPCR and the number of fungal propagules present in artificially inoculated soils. The effectiveness of the assay was validated by comparing it to traditional methods for the detection of F. solani in diseased strawberry plants and pre-planting soils from strawberry fields. A substantial and moderate correlation was found between the qPCR-based and traditional detection methods in diseased plants and soils. The amount of F. solani DNA estimated in roots and crowns of symptomatic strawberry plants ranged from 16 to 190pg/mg fresh tissue. Inoculum densities in preplanting soils varied between 3.1 x 10(2) and 1.3 x 10(5) colony-forming units per gram (CFU/g) of soil. Effectiveness was also evaluated by assessing the ability of the assay to detect decreasing levels of F. solani populations during biosolarization treatment. Taken together, this novel qPCR assay represents a useful tool for rapid assessment of pre-planting soils and nursery plants to prevent F. solani infection and production losses.

The impact of methyl bromide (MB) phase-out on important fruit and nursery industries in the EU (2005/2008) has been significant. Under EU Regulation 1107/2009, MB fumigant alternatives 1,3-dichloropropene and chloropicrin were also phased out (in 2010 and 2013, respectively) while dazomet, metam sodium, and potassium were re-approved with crucial restrictions of rates and years of application. However, currently an EU Member State may authorize use of these phased-out fumigants for 120 days/year. This exemption has been used for strawberry (fruit and nursery production) and other crops in Spain, Italy, Belgium, France, UK, Cyprus, Malta, and Greece in recent years. To provide an update of the current situation, a comprehensive survey of 41 European and other industries has been completed. Most of them use crop rotation as the main pest management solution. Non-chemical solutions, in particular soilless cultivation, are important in the UK, Ireland, France, the Netherlands, and Belgium. Chemical fumigation is still important in Spain, Italy, Morocco, Turkey, France, and Belgium.

Since 1997, our IFAPA working group has developed a series of projects to evaluate new chemical and non-chemical soil disinfestation practices. During 2013-14 non-chemical (biological) alternatives have been tested with the objective of improving the biosolarization techniques, using different carbon sources and doses of organic biofumigant products under different types of plastic tarp. Throughout the growing season, the greatest production for cv. Florida Fortuna (52,672 kg/ha, by the end of May) was obtained with biosolarization using dried olive pomace (12,500 kg/ha) and virtually impermeable film; whereas biosolarization with chicken manure at 25,000 kg/ha had the lowest fruit production (42,517 kg/ha) among biosolarization treatments. Biosolarization treatments significantly reduced soil populations of M. phaseolina and Fusarium spp., and effectively suppressed nematode infestation.

There is an increasing demand in the market to improve strawberry quality by promoting human-health compounds content, as these may play a significant role in the prevention of chronic diseases. Strawberry cultivars, environmental conditions, and agronomical conditions have an effect on fruit characteristics; therefore, it is necessary to constantly generate information about the cultivar response to different production areas and cultural practices. The goal of this work was to evaluate the effect of two planting dates, two harvest dates, and four strawberry cultivars on total phenolic acid (gallic acid equivalent), ascorbic acid (vitamin C), and soluble solid content.titratable acidity-1 (SSC.TA-1) ratio in Huelva, Spain. Sixteen treatments resulted from the combination of four cultivars, two planting dates, and two harvest dates. Strawberry 'Camarosa', 'Sabrosa', 'Aguedilla', and 'Fuentepina' were selected for both seasons and planted on 7 Oct. (early planting) and 21 Oct. (late planting). Mid-February and mid-April were considered early and late harvest, respectively. Nutraceutical and organoleptic responses were specifics for each cultivar. The highest SSC.TA-1 ratio was observed in 'Fuentepina' planted late and harvested early. 'Aguedilla' resulted in the highest phenolic content when harvested in the late season. Additionally, phenolic content was significantly higher when using late planting combined with late harvest in most of the cultivars. Late harvested 'Camarosa' showed the highest TA concentration, whereas 'Sabrosa' resulted in the highest SSC regardless of harvesting date. Additionally, 'Aguedilla' and 'Sabrosa' showed the highest ascorbic content. Strawberry quality could be improved by selecting the adequate planting and harvesting dates according to specific cultivars.

Strawberry is a high value crop worth 315.6 million euros in 2013 in Spain. Strawberry diseases are commonly controlled by soil fumigation with toxic chemicals. However, since 2007, the methyl bromide fumigant is banned for strawberry cultivation. Moreover, European policies are progressively restricting the use of other toxic fumigants such as dichloropropene. Alternative control techniques are thus needed. Therefore, we have tested soil biosolarization, a new technique combining soil biofumigation and soil solarization, to cultivate the Camarosa strawberry in 2010–12 at Huelva in the southwestern coast of Spain. Soil was biofumigated by amendment of fresh chicken manure at 12,500 kg/ha with or without Trichoderma at 3.5 kg/ha; chicken manure at 25,000 kg/ha; Brassica juncea pellets at 2,000 kg/ha; sugar beet vinasse at 15,000 kg/ha; or dried olive pomace at 12,500 kg/ha. Soil was then solarized for 30 days by covering with a clear plastic mulch. A control that received fermented manure remained uncovered. Our results show that the highest yield averaging 70,543 kg/ha and the lowest percentage of 12.6 % of second-class fruits were obtained by amendment of fresh chicken manure. Yields were also similar to the higher yields previously reported for chemical fumigation with 1,3-dichloropropene and chloropicrin. In addition, biosolarization is about 20 % cheaper than treatment with 1,3-dichloropropene and chloropicrin. Biosolarization with chicken manure is, therefore, a promising sustainable option for strawberry production.

Since 2000, the high significance of strawberry (Fragaria ·ananassa Duch.) production in Huelva, located on the southwest coast of Spain, has led public and private institutions to increase the releasing of new cultivars that are well adapted to the climate characteristics and growing conditions in Huelva and other mild areas. The Spanish public breeding program has contributed to this effort with cultivars such as ‘Andana’, ‘Carisma’, ‘Marina’, ‘Medina’, ‘Aguedilla’, and ‘Fuentepina’ (Bartual et al., 1997, 2002; López-Aranda et al., 2004, 2005a, 2005b; Soria et al., 2010). ‘Santaclara’ is a new short-day cultivar recently released by the Spanish public breeding program, participating in the Spanish National Agricultural Research Institute (INIA), the Andalusian Institute of Agriculture and Fishery Research and Training (IFAPA) as well as the private partners Fresas Nuevos Materiales S.A. (FNM), Freshuelva Viveristas (FV), and Nuevas Técnicas de Fresa S.L. (NTF). The main purpose of this program is to breed cultivars for high yield, large fruit size for the fresh market, and high fruit quality and which outperform currently grown shortday cultivars in mild climate areas (e.g., ‘Camarosa’). ‘Santaclara’ is noted for its mediumto high-balanced agronomic, postharvest, and fruit quality traits (including nutraceutic values). ‘Santaclara’ also showsexcellent comparative qualities for the fresh market and adapts well to mild agroenvironments. This new cultivar was named after an old monastery founded in 1337 and located at Moguer (Huelva), place of birth of the 1965 Nobel prize awarded poet Juan Ramón Jiménez, who spent his youth in the strawberry production area around this nice village.

The supply of strawberry (Fragaria x ananassa) cultivars in the world can be restricted by several factors, such as environmental adaptation (mainly latitude), type of bearing (short-day and day-neutral cultivars), and industry strategies, among others. This review selected the area between the 42°north and south parallels as a production area of mild climates with somewhat similar conditions. A compilation was done about the current situation of the strawberry industry focusing on cultivar utilization in the U.S. (California and Florida), Mexico, Chile, Argentina, Brazil, Uruguay, Portugal, Spain, France, Italy, Morocco, Egypt, Turkey, China, Japan, and Australia. These countries represent over 85% of the world production. The day-neutral cultivar supply currently is very limited in comparison with short-day utilization. There is significant evidence of a successful utilization of cultivars, such as ‘Albion’, ‘Florida Festival’, ‘Florida Fortuna’, ‘Splendor’, and ‘Sabrosa’. Japanese cultivars have predominance in China and Japan.

‘Fuentepina’ Strawberry Carmen Soria, Juan J. Medina, Pedro Domı́nguez, Marı́a T. Ariza, Luis Miranda, Rosalı́a Villalba, Josefa Gálvez, José F. Sánchez-Sevilla, Iraida Amaya, Rafael Sesmero, and José M. López-Aranda Instituto Andaluz de Investigación y Formación Agraria y Pesquera (IFAPA), Consejerı́a de Agricultura y Pesca, Junta de Andalucı́a, Avda. Isaac Newton n 3, 2 planta, Parque Tecnológico Cartuja ‘93, 41092 Seville, Spain

Field trials were conducted in two locations in Spain to determine the effect of methyl bromide (MBr) alternatives on soilborne diseases and nematodes, and strawberry (Fragaria ×ananassa) yields under high-tunnel conditions. Fumigant treatments were applied to the same plots each year. Treatments were MBr + chloropicrin (Pic) (50:50, v/v) at a rate of 400 kg·ha−1; 1,3-dichloropropene (1,3-D) + Pic (65:35, v/v) at 300 kg·ha−1; Pic at 300 kg·ha−1; dimethyl disulfide (DMDS) + Pic (50:50, v/v) at 500 kg·ha−1; propylene oxide at 550 kg·ha−1; dazomet at 400 kg·ha−1; and calcium cyanamide (Ca-cyanamide) at 700 kg·ha−1. A nontreated control was also included. Fumigation with MBr + Pic, 1,3-D + Pic, Pic, and DMDS + Pic consistently improved early and total marketable strawberry yields in both locations. This response was caused by successful soilborne fungus and nematode control, improving strawberry growth and development, which resulted in increased plant canopy diameters and higher strawberry early and total yield.