Strawberry Cvs Research Articles

The influence of NaCl salinity on growth, yield and fruit quality of strawberry cvs. ‘Elsanta’ and ‘Korona’

In a 2-year field study, strawberry cvs. ‘Elsanta’ and ‘Korona’ were exposed to three different levels of NaCl salinity supplied as aqueous solutions characterised by electrical conductivities of 0.3 dS/m, 2.6 dS/m, and 5.1 dS/m. Salinity in the rhizosphere reduced plant growth by up to 44% in ‘Korona’ and 90% in ‘Elsanta’. A rather distinct cultivar difference represented the reduction in leaf area per plant of 85% in the second year of experiment in ‘Elsanta’ compared to 29% in ‘Korona’. Strawberry can be regarded as a Na + excluder, because Na + content of both strawberry cultivars remained below 3 mg g −1 dry mass at all salinity levels. Cl − content increased considerably, up to 70 mg g −1 dry mass in ‘Korona’ and 80 mg g −1 dry mass in ‘Elsanta’ plants. ‘Korona’ retained most of its Cl − in roots and crowns, whereas in ‘Elsanta’ the maximum was detected in petioles. ‘Korona’ was able to accumulate up to 33% higher Cl − content in the roots than ‘Elsanta’. Macronutrient deficiency due to NaCl salinity was not observed and in comparison to ‘Elsanta’, higher Cl − content in roots of ‘Korona’ did not coincide with an impairment of macronutrient uptake. Salinity stress reduced fruit yield by up to 27% in ‘Korona’ and 64% in ‘Elsanta’. Fruit quality, characterised as taste, aroma, and texture by a consumer-type panel, decreased by more than 24% in ‘Elsanta’, but in ‘Korona’ differences were insignificant. Total soluble solids (Brix) and the ratio Brix/TA (TA, titratable acid) decreased significantly by about 20% in ‘Korona’ and 35% in ‘Elsanta’. To summarise, the ability of ‘Korona’ to retain Cl − in the root system more effectively than ‘Elsanta’ resulted not only in a 41% lower leaf Cl − content at the highest salinity level and a better growth under NaCl stress, but also in a relatively higher fruit yield and fruit quality.

First Confirmation of Sphaerotheca macularis on Strawberry Plants in Southwestern Spain.

In February 2001, in seven small tunnel production fields in southwestern Spain, symptoms and signs of powdery mildew were detected on strawberry (Fragaria × ananassa) cvs. Camarosa, Andana, and Carisma. On 'Camarosa' plants, white patches of mycelium developed on the lower leaf surface. Later, the leaf edges rolled upward, and reddish or necrotic irregular spots appeared on the lower leaf surface. Some immature fruits were abnormally hard and covered with a dense white mycelium. Symptoms were much less severe on 'Andana' and 'Carisma'. Microscopic observations revealed conidia in chains, ellipsoidal to barrel-shaped, with fibrosin granules. Mean dimensions of conidia (N= 70) were 31.2 μm ± 2.8 × 20.39 μm ± 4.1. Cleistothecia were not detected. Based on these characteristics, the causal agent was identified as Sphaerotheca macularis (Wallr.:Fr.) Lind. (1). Pathogenicity was confirmed by inoculating leaves of 2-month-old potted 'Camarosa' plants. S. macularis obtained from field-grown plants was maintained on 'Camarosa' strawberry leaves in a growth chamber (20°C and 100% relative humidity). Inoculum was obtained from freshly sporulating infected leaves 11 days after inoculation. Conidia of S. macularis were gently brushed into 100-ml distilled water containing two drops of Tween 20. Ten strawberry 'Camarosa' plants were inoculated by misting with a conidial suspension (104 conidia per ml) (2). The plants were incubated at 100% relative humidity for 48 h in the greenhouse (15 to 25°C). Colonies of powdery mildew were observed on leaves after 18 days. To our knowledge, this is the first confirmation of S. macularis on strawberry in Spain.

Supplementary calcium enhances plant growth and fruit yield in strawberry cultivars grown at high (NaCl) salinity

Strawberry ( Fragaria × ananassa Duch) cvs. ‘Oso Grande’ and ‘Camarosa’ were grown in sand culture out-of-doors to investigate the effectiveness of supplementary calcium (Ca) applied into nutrient solution on plants grown at high (35 mM) NaCl concentration. Treatments were: (1) nutrient solution alone (C); (2) nutrient solution plus 35 mM NaCl (C+S); (3) nutrient solution and 35 mM sodium chloride plus supplementary 5 mM Ca as CaCl 2 supplied in nutrient solution (C+S+Ca). Dry matter, fruit yield and chlorophyll content of plants grown at high NaCl were less than those at normal nutrient solution. Supplementary Ca ameliorated the negative effects of salinity on plant growth and fruit yield. Water use by plants decreased with elevated NaCl and increased with supplementary Ca. Membrane permeability increased with high NaCl application and these increases in membrane permeability were decreased with supplementary Ca. Sodium (Na) concentration in plant tissues increased in both cultivars in the high NaCl level. Concentrations of Ca were at deficient ranges in the plants grown at high NaCl levels and these deficiencies were corrected by supplementary Ca.

Freeze injury to strawberry plants as evaluated by crown tissue browning, regrowth and yield parameters

The strawberry cvs `Bounty', `Korona' and `Senga Sengana' were frozen for 2 h at −8, −12, −16 or −20°C, at a freeze and thaw rate of 2°C/h. Growth and yield parameters and crown tissue browning were compared with plants stored at 0°C. At −8°C all the plants were severely injured and the fruit yields were reduced to 41, 60 and 66% of uninjured plants respectively for `Senga Sengana', `Bounty' and `Korona'. These yield reductions were reflected in reduced growth and increased crown tissue browning, and there were strong correlations between the different parameters recorded. It is concluded that the limit temperature for severe injury, for a single short term freezing, is between −8 and −12°C for `Bounty' and `Senga Sengana' and a little below −12°C for `Korona'. Plants frozen at −20°C died.

Occurrence of Colletotrichum acutatum, Causal Organism of Strawberry Anthracnose in Southwestern Spain.

A wilting disease of strawberry (Fragaria × ananassa Duchesne 'Oso Grande') was observed in production fields in Huelva, southwestern Andalucía, Spain. Crowns of wilted plants developed a reddish brown, firm rot. Longitudinal sections of roots of diseased plants showed a black coloration of the cortex. Symptons also included blighting of flowers due to floral infection and rotting of green and ripening fruits. On the fruit, the round, firm sunken lesions were covered with masses of salmon-colored spores. Lesions on the leaves were round, ranged in diameter from 5 to 10 mm, and were light brown with purple edges. Infected tissues were surface disinfected in 20% sodium hypoclorite, blotted dry, and plated on water agar. Dishes were incubated at 25°C; hyphal tips made of fungi growing from lesions were transferred to potato dextrose agar (PDA) and incubated under cool-white fluorescent light at 25°C. One fungus was isolated consistently from lesions on different tissues. It was identified as Colletotrichum acutatum by morphological characteristics (2) and enzyme-linked immunosorbent assay (1). On PDA, the mycelium of the fungus was white to gray and covered with salmon spore masses. Colony diameters on PDA averaged 45 mm after 7 days at 25°C. Hyaline, aseptate conidia were cylindrical, fusiform, and intermediate in shape and averaged 12.8 × 4.2 μm in size. The fungus produced setae on infected fruit. Inoculations of strawberry cvs. Oso Grande and Chandler with conidial suspensions (106 conidia per ml) of C. acutatum produced lesions on the fruit, petioles, and crowns, and caused wilt. The pathogen was reisolated from lesions on the inoculated plants. This is the first report of C. acutatum causing strawberry anthracnose in Huelva.

Rowcover Effects on Growth and Yield of Strawberry Cultivars Grown in a Mediterranean Climate

Abstract Rowcover application has had variable effects on yield, depending on growing conditions. Strawberry (Fragaria × ananassa Duch) cvs. Chandler, Milcin, Milsei and Oso Grande response to rowcover was studied under a plasticulture-tunnel system on the Mediterranean coast of Beirut. Flowering and leaf number early in the season were comparable among covered and non-covered control groups. Rowcover reduced fruit yield and number in all cvs., primarily by the reduction in fruit number. Cultivars varied in yield, irrespective of the cover treatment and in yield distribution during the four months of harvest. The shading effect of rowcovers offset the effect of the slight rise in soil temperature (1-2°C) it caused. Soil chemical properties and NO3-N and P content in plant tissue were not affected by the treatments. Red spider mite (Tetrany-chus urticae Koch.) infestation started about two months after removal of rowcovers. There was no difference in the level of infestation due to treatments. We recommend...

Investigations on Yield an Quality Characteristics of Some Stawberry Cultivars Grown Under Adana and Pozanti Ecological Conditions

These investigations were carried out during 1991-92 and 1992-93 seasons in Adana (altitude: 50m) and Pozanti (altitude: 1100m) ecological conditions in order to compare the behaviour of 8 strawberry cvs (Aliso, Tioga, Tufts, Vista, Pocahontas, Cruz, Douglas and Dana) with summer planting system. The plantings were repeated each year in Adana but the plants of the first year were kept in their places and their second crop was obtained in second year. During 1991-92 season the yield per plant in Adana was found much higher than that of the Pozanti. However, since the second crop of Pozanti's plants was quite satisfactory, this type of growing is recommended. In Adana spring rains during the flowering and peak season reduce the yield therefore here protected cultivation is recommended. When the yield/plant, average size of the fruits, TSS were considered, Tufts, Vista and Cruz were found superior than the other cvs tested.

Development of two spotted spider mite (Acari: Tetranychidae) populations on strawberry and raspberry cultivars

Summary.Five strawberry (Fragaria sp.) and five raspberry (Rubus ideaus L.) cultivars were evaluated for resistance to two spotted spider mite (Tetranychus urticae Koch.). Two methods of assessing the development of two spotted mite populations using detached leaves were compared. The number of eggs laid and mites which developed were compared. The strawberry cvs Hapil and Pegasus had significantly greater development of two spotted mite populations than the cvs Rhapsody, Symphony and Elsanta. The raspberry cv. Joan Squires had higher populations of two spotted mite whilst the raspberry cv. Leo the least, when compared with cvs Glen Clova, Glen Moy and Glen Prosen. Differences were observed in oviposition sites and mite distribution when comparing raspberries with strawberries. The method of assessing the populations development of two spotted mite which involved maintaining the cut leaf stem in water may be of potential use for studying population dynamics of both two spotted mite and possible predators over extended periods of time.

Micropropagation of strawberry (Fragaria x ananassaDuch.). Effect of mineral salts, benzyladenine levels and number of subcultures on the in vitro and field behaviour of the obtained microplants and the fruiting capacity of their progeny

SUMMARYThe effects of different salt formulations and benzyladenine levels on in vitro culture of strawberry cvs Douglas and Chandler were studied. While the N30K salt formulation is adequate for both cultivars, BA requirements differ. Best results on rooting were obtained with either the Knop or N30K salt formulations. Addition of 500 mg I' activated charcoal also enhanced rooting; in contrast, high BA levels during multiplication decreased the rooting capacity of shoots. Micropropagated plants showed a higher runner production capacity than their control counterparts. This increase in quantity was not linked with decreased quality. Salt formulations, BA levels (1.48-4.44 uM) and the number of subcultures (1-8) seemed not to affect the behaviour of plants in the nursery. No adverse effects on total fruit production or fruit size could be associated with the mineral formulations used during the in vitro phase, high BA concentrations adversely affected total fruit production although differences between t...

東北・北海道におけるイチゴ黒斑病菌の分離菌株に対するイチゴ‘盛岡１６号’の体細胞変異株‘Ｍ１６‐ＡＲ１，２および３’の抵抗性

In order to confirm the resistance of 'M16-AR 1, 2 and 3' to isolates of Alternaria alternata strawberry pathotype occurring in Tohoku and Hokkaido, 'M16-AR' lines were inoculated with 8 isolates of the pathogen collected from 8 municipalities in both districts.Conidia of these 8 isolates were morphologically undifferentiable. However, the isolates differed slightly in their cultural characters.As a result of inoculating each of 8 isolates into leaf blades of various test plants, black spot, a typical symptom of this disease was formed only on strawberry cvs. Morioka-16 and Robinson and the Japanese pear cvs. Nijisseiki and Shinsui. Thus, it was confirmed Ithat the host range of the isolates was not different from that of Alternaria alternata strawberry pathotype reported previously in Japan.'M16-AR' lines inoculated with the 8 isolates were found to be resistant. Furthermore, these lines cultured for three years (1989 to 1991) under field conditions were not affected by Alternaria black spot of strawberry. Consequently, it seems that selections of 'M16-AR' lines may be the preferred cultivars to plant instead of 'Morioka-16' for Tohoku and Hokkaido in Japan.

PLANT AND INSECT AGE AS FACTORS IN THE TRANSMISSION OF CLOVER PHYLLODY (GREEN PETAL) AGENT TO STRAWBERRY BY APHRODES BICINCTUS

Plants of various ages of strawberry cvs. Redcoat and Sparkle were exposed to Aphrodes bicinctus leafhoppers carrying clover phyllody agent (CPA). The susceptibility of Redcoat decreased with age but this effect was less obvious with Sparkle. The ability of A. bicinctus to transmit CPA to Sparkle also decreased as the insects aged after they had acquired the causal agent. No differences were observed between two isolates of CPA in their transmission to four strawberry cultivars. Redchief and Sparkle were the most susceptible cultivars with approximately 67% of the plants becoming infected. Redcoat and Bounty showed infection rates of 39% and 46%, respectively.

Growth and wilt (Verticillium dahliae) development in strawberry cultivars over a transition between two soil series

SUMMARYOn a site infested with V. dahliae the incidence of wilt was low consistently in strawberry cvs Talisman and Redgauntlet, high in Merton Herald and Gorella, and very high in Merton Ruby, Cambridge Vigour, Prizewinner, Templar and Crusader.Changes in mean volume per plant for the whole population of each cultivar were closely related to disease incidence and therefore differed between high‐resistance and low‐resistance cultivars.Height and spread measurements of diseased and symptomless plants in certain cultivars showed differences in the severity of the effect of the pathogen on growth that were not closely related to wilt incidence.Gradients of disease incidence and plant growth in 1966 and 1967 were associated with a transition from one soil series to another. Review of two earlier experiments on the same site revealed a similar gradient of disease incidence in 1963‐64, but a reversed gradient in 1960‐62. Variations related to soil conditions were smaller in the earlier experiments than in 1966‐67.