Strawberry Growth and Flowering

Abstract

Strawberry is an herbaceous perennial that can be easily propagated by stolons or by crown division. Seedlings have a few months in the juvenile period. The growth is determined with a terminal inflorescence as a modified stem or cyme. Flower induction is sensitive to thermo-photoperiod and to several agronomic and nutritional factors. The strawberry plant is highly adapted to diverse temperate climates and to production under forced artificial growing conditions. In the present study, a dynamic architectural model of growth is described and discussed in order to reveal strawberry development under different cultivation systems. The aim is to improve the cultural knowledge and understanding of the physiological control of axillary meristems, which can enhance the Strawberry fruit production.     

Strawberry Growth and Development in the Mild Winter European Regions

Abstract

In the mild winter regions strawberries are the most important crop of the small fruits. Strawberry production systems rely on the ‘winter’ planting system developed in California for early production and predominantly on California cultivars with plants set at high densities. The aim of this paper is to provide a brief review of strawberry growth and development in the mild winter regions based on a review of the literature and on research studies carried out in southwestern Portugal.     

Historical Milestones,Current Methods,and Strategies Resulting in Year-Round Strawberry Production in Belgium

ABSTRACT

Strawberry production in Belgium has evolved from being a June-harvested crop grown in soil to a year-round crop grown in multiple production systems, as a result of the development of new cultivars and production techniques. Strawberry cultivation used to be one aspect of diverse family enterprises, but now strawberry farms are specialized. In the beginning, strawberries were only harvested in June. Covering the crop with plastic tunnels allowed the harvest to advance to May. Subsequently, an important innovation was the use of cold-stored plants in year-round plantings, which also allowed later production. This evolution in combination with the development of various cultivation systems using peat substrates (including table-tops, plastic greenhouses, and glasshouses) resulted in a strawberry production period from March until December–January. Recently, interest in assimilation lighting in glasshouses has increased. At first, this allowed advanced production in February, but now even winter production is possible, resulting in fresh Belgian strawberries 365 days a year.     

Evaluation of Strawberry Genotypes for Chaetosiphon fragaefolii (Strawberry Aphid) Preference

ABSTRACT

Thirty-one strawberry genotypes were evaluated for supporting the reproductive success of the strawberry aphid (Chaetosiphon fragaefolii), a vector of several strawberry viruses. A pure colony of C. fragaefolii was initiated from eggs collected from field strawberry leaves in Fall 2013. In Spring 2014 greenhouse-grown strawberry plants with four to five leaves were placed in screened cages (16 genotypes/cage) and five aphids were placed on each plant. After 30–32 days, the number of aphids in each of four developmental stages was counted on each plant. Total aphid numbers/plant ranged from a mean of 33 on Fragaria chiloensis CFRA 48 (PI 551459) to 279 on F. × ananassa ‘AAC Lila’. Cultivars with relatively low numbers of aphids included ‘Bounty’ (106 aphids), ‘Mira’ (114 aphids), and ‘Annapolis’ (115 aphids). This experiment, part of a larger project on aphids and virus diseases associated with the cultivated strawberry, will inform decisions in the strawberry breeding program.     

Effect of Planting and Harvesting Dates on Strawberry Fruit Quality under High Tunnels

ABSTRACT

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.     

Phloem unloading follows an extensive apoplastic pathway in developing strawberry fruit

Summary

Strawberry (Fragaria × ananassa) is widely used as a model for fleshy fruit biology research; nevertheless, the pathway of phloem unloading in strawberry fruit remains unknown. Using transmission electron microscopy (TEM) and the symplastic tracer, carboxyfluorescein, the phloem unloading pathway was studied in ‘Akihime’ strawberry fruit from post-anthesis to the ripening stage. Ultrastructural analysis showed that many plasmodesmata existed between the sieve element cells (SEC) and the companion cells (CC), but plasmodesmata were absent between the sieve element cell – CC complexes and their surrounding phloem parenchyma cells (PPCs). Interestingly, an abundance of plasmodesmata was observed between parenchyma cells. Imaging of carboxyfluorescein unloading revealed that the dye was confined only to the phloem vascular bundles in developing receptacles. In conclusion, the results obtained from the present study indicate that sugar unloading from the phloem occurs through an apoplastic pathway. Post-phloem transport of sugar then follows a symplastic pathway in strawberry fruit.     

Cold Storage of Strawberry Plants

Abstract

Cold storage has not only been a good method to overwinter strawberry plants safely and to compensate for the lack of natural chilling. Initially cold stored plants were used for early spring cropping only. Meanwhile this technique has become a normal commercial practice among growers in central Europe and has given them the opportunity to extend the strawberry production season from July until January. Cold stored waiting bed plants have been used since the early seventies in The Netherlands and Belgium and currently represent an important part of strawberry production. These sixty-day-plants are planted mainly outdoors in the soil for a production from July until September. More recently waiting bed plants have gained popularity in the UK, Germany and northern Italy to extend the season. Alternatively in France and Germany cold stored runner (A+) plants are traditionally being used for a summer production outdoors followed by a spring crop. During the last decade module or tray plants have gained popularity for autumn cropping on substrate culture in plastic tunnels and greenhouses. During the most recent years the programmed “out of season” production of strawberries has become more important in several European countries. Intensive research has been going on concerning the improvement of the growing techniques and quality of plant material and cold Storage conditions.     

Breeding Strawberry for Higher Phytochemicals Content and Claim It: Is It Possible?

ABSTRACT

Commercial strawberries (Fragaria × ananassa) are one of the most investigated berries for nutritional and nutraceutical properties. A strawberry breeding program, including inter-specific back-crosses, is now producing new genotypes with increased vitamin C, folates, and phenols combined with important commercial traits. The release of new cultivars with a high content of bioactive compounds, which may contribute to health, wellness, and reduced disease risk, is expected from this program. The ultimate goal is to properly obtain and integrate new scientific knowledge from genetic, agronomic, and biomedical studies that may bring acceptance from food agencies for specific health claims on new strawberry cultivars.     

Arbuscular mycorrhizal fungi communities improve the phytochemical quality of strawberry

The application of arbuscular mycorrhizal fungi (AMF) in strawberry cultivation can improve its growth and development. The objective of this study was to evaluate if strawberry plants in the absence and presence of inoculation with AMF communities, obtained from soils collected in reference-sites in the cultivation of this species, differ in their morpho-horticultural performance. Two experiments were carried out: in experiment I (frequency of AMF communities species) the treatments were eight soils containing AMF communities, collected from natural and agricultural ecosystems in reference-sites of strawberry cultivation in southern Brazil, with nine samples per treatment; in experiment II (use of AMF communities in strawberry) the treatments were eight AMF communities and one control (non-mycorrhizal plants), arranged in a completely randomised design, with three replicates. The species Claroideoglomus aff. luteum, C. claroideum, C. etunicatum, Funneliformis mosseae and Glomus sp2 were the most frequent in the studied sites and the morpho-horticultural performance of strawberry plants was improved when plants inoculated with AMF communities. Strawberry plants inoculated with mycorrhizae develop a more profuse root system and fruit anthocyanin content is increased.     

Increasing Number of Drip Irrigation Lines for Water Conservation during Strawberry Establishment

ABSTRACT

Strawberry transplants in California are planted through narrow holes in raised beds covered with polyethylene mulch. They are irrigated with overhead sprinklers for the first five weeks to leach salts and maintain plant turgidity; most of this sprinkler-applied water runs off the plastic without reaching the plants. At three coastal locations, we compared grower controlled drip irrigation with doubled number of tapes to sprinkler irrigation immediately after planting. Root zone EC and moisture levels were similar in both irrigation systems. Depending on the location, water use was reduced 24 to 78% in drip-only plots compared to sprinkler and runoff was nearly eliminated. Plants in drip-only plots were similar in size and root biomass to those established with sprinkler irrigation. Early yields were similar in the two irrigation systems. Thus, use of the increased number of drip tapes conserves water during strawberry establishment without negative effects on plant performance.     

Strawberry Production in Central Europe

Abstract

This paper focuses on the cropping systems in central European countries such as Belgium, The Netherlands, UK, Ireland, Germany, Switzerland and the northern part of France and Italy. During the last decade there has been a consistent increase in programmed “out-of-season” strawberry production in several central European countries. This is being achieved in part, by using cultivars with different cropping seasons, but mainly by sequential planting of cold-stored plants and by growing strawberries in greenhouses and plastic tunnels. These methods have made it possible to extend the strawberry production for 11 months, from the end of February until mid January in central European countries with moderate climates.     

Status of Macrophomina phaseolina on Strawberry in California and Preliminary Characterization of the Pathogen

ABSTRACT

Macrophomina crown and root rot has become a significant soil-borne disease issue in California. For many locations in the state, the disease is associated with fields that are no longer pre-plant, flat field fumigated with methyl bromide + chloropicrin. Inoculation experiments indicated that some differences in strawberry cultivar susceptibility to Macrophomina phaseolina were seen a short time after the inoculation, but as disease progressed such differences did not persist. Preliminary characterization studies of Macrophomina phaseolina isolates from strawberry indicated that such isolates may have a host preference for strawberry. Macrophomina phaseolina isolates from watermelon, thyme, and apple failed to cause disease in strawberry. Five cover crop species, which can be rotated with strawberry, did not develop disease when inoculated with strawberry isolates. In preliminary analysis using simple sequence repeat markers, isolates obtained from strawberry formed a separate group compared to isolates recovered from other known Macrophomina phaseolina hosts.     

Vom Luxusgut der Kapitalisten zum Exportschlager – Erdbeeranbau, Vermarktung und Züchtung in China als drittgrößter Erdbeerproduzent weltweit

The 23% consolidation of China's strawberry industry from 70,000?ha in 2005 to 53,000?ha in 2006 due to extreme climate conditions reduced production from 840,000?t to 650,000?t. This tonnage includes a 40% market share for processing for the home market (150,000– 190,000?t) and frozen fruit for both the home market and export (70,000–90,000?t) and makes China the world's third largest strawberry producer after the US and Europe. Strawberry cultivation in China is characterised by family smallholders with an averaged acreage of ca. 2,000?m² and salaries of 2?euros/person/day for hired labour resulting in ca. 500?euros/1,000?m² gross return. The major growing regions are the provinces Hebei (near Baoding), Shandong, Liaoning with an acreage of ca. 10,000?ha each. Strawberry plants and varieties are imported, but new Chinese varieties such as ‘Chun Xing’, ‘Xing Du 1 and 2’, ‘Xuemi’ and ‘Chun Xu’ are increasingly grown. The Chinese varieties are characterised by their sweet flavour with low acidity, a pre-requisite for the Asian market, and good taste and are adapted to the respective growing climate. A portion of the strawberry harvest is used for processing due to insufficient external fruit quality such as size, shape and colour by European standard. Strawberry research in China is spread between 9 institutions and universities throughout the country. Strawberries were regarded as exclusive desert and luxury for the upper class during the ten years of the cultural revolution between 1966–1976 under Mao Zedong. Today, fresh strawberries are sold in street markets or supermarkets. Import of strawberry fruit is prohibited, except for Hongkong, which imports 2,200?t from China and the US. China's export of 76,000?t in 2005, equivalent to a 9–10% export rate, was shipped to Japan (11,000?t) and Germany (8,700?t) with dumping prices below 50?cent/kg.     

大棚草莓新品种红颊抗性比较与繁苗试验

对红颊、佐贺清香、丰香草莓进行塑料大棚促成栽培,对其繁苗率、发病率、成苗率进行比较试验。结果表明,红颊、佐贺清香的成苗率均高于丰香;红颊前期产量和总产量高于丰香,可以作为如皋市草莓设施栽培的主栽品种。     

草莓果实磷脂酶D活性的测定

以草莓果实为试材,建立了适合草莓果实组织磷脂酶D制备及活性测定的技术体系。以放射标记的磷脂酰胆碱为底物,在1mL反应体系中,膜蛋白的含量以5-10μg为宜;25℃反应温度下,反应时间以5-10min为宜;反应体系的适宜pH为6.5-7。对草莓果实不同组分磷脂酶D酶学特性的进一步分析认为,该技术体系的建立有助于进一步探讨磷脂酶D在草莓果实发育成熟和衰老进程中的作用。     

Effects of Organic Residues on Strawberry Root Growth

Abstract

Strawberries are often replanted in the same field as a single crop or in short rotation cycles causing a progressive deterioration of the soil. The present study was conducted to clarify the growth response of strawberry roots to increasing amounts of strawberry residues. Observation boxes were built using glass windows and filled with commercial compost. In order to simulate the soil accumulation of strawberry plant residues a 3-cm layer with a residue concentration ranging from 0 to 100% was prepared 15 cm from the soil surface. The roots were observed for three weeks starting five days after planting. The root growth was reduced by the presence of the residues. After the first week, the lowest growth was found with the 30% residue treatment. After the primary roots entered the layer containing residue the growth was further reduced in the 100% residue treatment, but the primary roots showed only a slight or no dimorphism when they encountered the layer. The lowest residue treatment did not reduce root growth compared to control and even positively stimulated it. When 30 and 100% residues were applied the above ground plant growth was also negatively affected. These results indicate that strawberry residues at high doses inhibited both primary and secondary root growth and changed the root dynamics in the substrate as a result of possible toxic effect.     

台湾草高架化——离地栽培模式

草莓为大众所喜欢的水果,传统的栽培方法劳动强度大,改为离地栽培方式后,不仅莓农不需再弯腰栽培及采果,操作方便、省工省力；而且离地栽培,基质通气性好,没有土壤病害的问题,可大幅降低农药使用量,提高产量和产值.     

Effects of Runner Tip Size and Plugging Date on Fall Flowering in Short-Day Strawberry (Fragaria × ananassa Duch.) Cultivars

Abstract

Producing strawberry transplants from runner tips that were plugged ～1 month earlier (early July) than the standard time (early August) promoted fall flowering in some short-day strawberry cultivars. In 2002,100% of ‘Chandler’ transplants produced in early July flowered in the fall, but none of the August-plugged ‘Chandler’ transplants flowered in the fall. In 2003, 73% of ‘Chandler’ transplants produced in mid-July from average-size runner tips and less than half of transplants from small-size runner tips flowered in the fall. Again, August-plugged plants did not flower in the fall. Flowering was absent in ‘Northeaster’ plants. Under protected cultivation, July-plugged ‘Sweet Charlie’ plants bloomed earlier and produced more fruit in November and December than those plugged in August. This study showed that fall flowering in ‘Chandler’ and ‘Sweet Charlie’ strawberry is possible if the transplants are prepared by plugging runner tips in early July. This novel technique for propagating strawberry transplants for annual plasticulture combined with production under high tunnels creates an opportunity for strawberry production in early winter and again in the spring (double cropping) in the mid-Atlantic coast region.     

Studies on the variability,inheritance, and inter-relationships of mineral macro-nutrients and micro-nutrients in strawberry (Fragariaananassa Duch.)

Summary

Strawberry (Fragaria ananassa Duch.) is a rich source of minerals, vitamins, and anti-oxidants, and has a unique flavour and aroma. However, there is little information on the genetic variability and inheritance of mineral elements in strawberry. This is important as it can influence the selection of better genotypes and suitable breeding approaches for improvements in the nutritional quality of fruit. The objectives of the present study were, therefore, to estimate the variability, inheritance, and inter-relationships of mineral elements, to identify mineral-rich and productive genotypes, and to suggest suitable breeding approaches. A significant genotypic mean square for all the minerals studied indicated sufficient variation among genotypes. Our results also indicated that the effect of genotype on the mineral content of fruit was stronger than that of environment. Six genotypes, namely ‘Ofra’, ‘Sweet Charlie’, ‘Elista’, ‘Festival’, ‘Camarosa’, and ‘Douglas’ were found to have higher mineral contents as well as better fruit yields, and therefore could be useful in further breeding programmes. N, K, Ca, Mg, Fe, Mn, Zn, and Cu contents, together with fruit yield, could be improved by selection and hybridisation as these traits showed high heritability (> 80%) and high genetic advance as a percentage of the mean (> 40%), while recurrent selection was suitable for increasing P contents, which showed moderate heritability (> 79.81%) and low genetic advance as a percentage of the mean (> 33.86%). Moreover, Mg and N contents could be used as reliable tools with which to identify the most productive and mineral-rich genotypes, as indicated by correlation and path analysis. Studies on such genetic estimates will increase our understanding of the inheritance of mineral contents and affect the design of crop improvement strategies.