Strawberry Production Research Articles

Plant biostimulants as natural alternatives to synthetic auxins in strawberry production: physiological and metabolic insights.

The demand for high-quality strawberries continues to grow, emphasizing the need for innovative agricultural practices to enhance both yield and fruit quality. In this context, the utilization of natural products, such as biostimulants, has emerged as a promising avenue for improving strawberry production while aligning with sustainable and eco-friendly agricultural approaches. This study explores the influence of a bacterial filtrate (BF), a vegetal-derived protein hydrolysate (PH), and a standard synthetic auxin (SA) on strawberry, investigating their effects on yield, fruit quality, mineral composition and metabolomics of leaves and fruits. Agronomic trial revealed that SA and BF significantly enhanced early fruit yield due to their positive influence on flowering and fruit set, while PH treatment favored a gradual and prolonged fruit set, associated with an increased shoot biomass and sustained production. Fruit quality analysis showed that PH-treated fruits exhibited an increase of firmness and soluble solids content, whereas SA-treated fruits displayed lower firmness and soluble solids content. The ionomic analysis of leaves and fruits indicated that all treatments provided sufficient nutrients, with heavy metals within regulatory limits. Metabolomics indicated that PH stimulated primary metabolites, while SA and BF directly affected flavonoid and anthocyanin biosynthesis, and PH increased fruit quality through enhanced production of beneficial metabolites. This research offers valuable insights for optimizing strawberry production and fruit quality by harnessing the potential of natural biostimulants as viable alternative to synthetic compounds.

Application of microalgae-based biostimulants in sustainable strawberry production

Application of microalgae-based biostimulants in sustainable strawberry production

Opportunities and challenges for strawberry cultivation in urban food production systems

Societal Impact StatementCultivation of strawberry plants in urban production systems, whether in green open‐air spaces or under some form of protected horticulture such as vertical farming, has demonstrated to be challenging to new farmers and businesses. Commercial strawberry producers have an advanced understanding of strawberry plant physiology, enabling them to grow the crop successfully and profitably. Lack of knowledge exchange between commercial growers and new urban farmers seems to result in the abandonment of strawberries as crop of choice in urban systems. This review will confront the specific plant science challenges urban growers need to address to incorporate this nutritional crop into their revolutionary urban growing systems, whilst achieving good quality produce with high yields.SummaryTo ensure a sustainable future of farming, urban horticulture (UH) will need to be a key part of our everyday life. There are increasing demands for higher productivity and more locally produced food, even close to densely populated urban areas, to address environmental pressures and accelerate the resilience of modern food systems. UH is a broad term and can include numerous cultivation methods; rooftop gardens, public spaces, vertical walls, indoor vertical farms, as well as an array of crops including, salads, soft fruits and trees. Crops such as strawberries are expected to soon make a significant contribution to UH. Urban strawberry production promises all‐year round fruit availability, reduced reliance on imports, increased self‐sufficiency, lower food miles, a supply of high‐quality fresh fruits from hyper‐local spaces, increased employment opportunities, welfare benefits and an opportunity to promote a sense of community. Strawberry is a complex perennial crop with agronomical challenges, which requires specialist knowledge that is not always available to new urban farmers. Achieving an urban version of a strawberry field will require knowledge exchange between the commercial rural strawberry producers and the newly entered urban growers. Plant physiology, management of plant pathogens, choice of propagation material, fertigation, pollination and environmental requirements are the most common challenges for urban strawberry production. This review aims to consolidate the common bottleneck challenges of UH for new urban strawberry facilities.

Effect of Sequential Crop Termination and Bed Fumigation on Verticillium dahliae Soil and Plant Density in Strawberry

ABSTRACT Verticillium dahliae, the causal agent of Verticillium wilt of strawberry, is a major soilborne pathogen in California strawberry production. Recent shifts in disease management have necessitated alternative methods for disease control. Two field experiments were conducted to examine the efficacy of sequential fumigant applications for crop termination and bed fumigation to reduce Verticillium dahliae inoculum density in a naturally infested field. Fumigant efficacy was evaluated for crop termination and for reducing pathogen survival in host tissue. Crop termination was conducted using metam potassium and metam sodium. Bed fumigation was conducted using both metam products and chloropicrin. For plots that were subject to both crop termination and bed fumigation, inoculum levels were somewhat reduced (3–6 CFU/g of soil) but not to a level below the disease threshold for strawberry (2 CFU/g of soil). Plots subjected to crop termination with metam potassium and bed fumigation with chloropicrin resulted in the lowest V. dahliae inoculum density. Injury due to crop termination ranged from 53% to 77% at 7 days after fumigation (DAF) and 73–89% at 14 DAF. The odds ratio of V. dahliae survival in the terminated crop were lower than in crops not terminated and V. dahliae survival was less likely at 14, compared to 7 DAF. In the crop terminated with metam potassium, the odds ratio of pathogen survival in the petiole versus the crown was 0.9–1.4. This research shows that crop termination could constitute management strategies for Verticillium wilt of strawberry.

Improvement in productivity of strawberry (Fragaria X ananassa Duch.) under vertical farming system

Vertical farming has evolved keeping in view the constraints of space due to the increasing population and shrinking agricultural land. Although vertical farming is more associated with small-duration crops, especially vegetables, flowers, and annuals such as strawberry can also be grown through the selection of appropriate variety and farming structure. An experiment was conducted to evaluate the effect of full spectrum light on the growth, flowering, fruiting, and yield of strawberry under a vertical farming system. Results revealed that plant height, plant spread, petiole length, number of leaves, number of fruits, average berry weight, and average yield were highest at light intensity of 175–200 μmol s-1m-2. It was observed that in T1 when plants were at the fourth level or top level (L4) of verticals under natural light, were superior in comparison to plants at lower levels in T2 (L3), T3 (L2), and T4 (L1) due to decreasing light intensity down to the base of verticals. The plants grown with an additional supply of artificial full spectrum light (AFSL) at these lower levels had performed better in T5 (2 h at L3), T6 (4 h at L2) and T7 (6 h at L1) in terms of growth, flowering, fruiting, and yield of strawberry and were at par to T1. In the vertical farming system, space, water, nutrient, and light optimization is possible as it ensures efficient resource utilization such as precision agriculture. Thus, the supply of AFSL is important to ensure sustainable yield in vertical farming.

CLIMATIC FACTORS FOR GROWING AND PRODUCING STRAWBERRIES IN IRAQ

The research aims to study the appropriate climatic ingredients for the cultivation and production of strawberries in Iraq. The study concluded that the climatic ingredients for cultivating and producing strawberries are available in a way that is compatible with the cultivated varieties in Iraq, and the extensive areas of strawberry cultivation in Iraq are concentrated in (Baghdad, Diyala, Salahuddin), in When the area planted with strawberry crops decreases in (Wasit, Karbala), either in terms of total productivity, it was occupied by Baghdad Governorate at the highest total productivity of strawberry crops, either the lowest total product The relationship relationship recorded between the regular rates of temperatures and the total production, while the relationship of the link was weak between solar radiation and the total production.

Bee Vectoring Technology Using Clonostachys rosea as a Biological Control for Botrytis Fruit Rot of Strawberry in Florida

Botrytis fruit rot (BFR), caused by Botrytis cinerea, is a major strawberry disease. The intensive use of fungicides for its management has resulted in resistance to several fungicide groups, requiring alternatives to BFR management. In this study, we evaluated the efficacy of bee vectoring technology (BVT) using Clonostachys rosea as a fungal biological control agent for BFR. BVT involves the use of bumble bees to carry C. rosea to strawberry flowers, where it can compete with B. cinerea. Three experiments were conducted on commercial farms in Florida during the 2016–17, 2017–18, and 2018–19 strawberry seasons. Treatments consisted of a nontreated control, fungicide standard program, BVT, and BVT + fungicide program. Fruits were harvested twice a week throughout the season to determine BFR incidence and yield, and postharvest activity was quantified during selected harvests. Temperature effect on mycelial growth was also determined for B. cinerea and C. rosea. The BVT + fungicide program reduced BFR incidence compared with the nontreated control in all seasons. However, BVT treatment by itself was not effective in improving yields or reducing disease incidence, likely due to highly favorable weather conditions for BFR in Florida. In addition, the low attractiveness of strawberry flowers to bumble bees and the fact that C. rosea is a better colonizer of strawberry leaves than flowers could also be limiting the effectiveness of BVT. Therefore, the BVT may be used in combination with fungicides to reduce BFR in strawberry production in Florida, but its cost-effectiveness still needs to be determined.

New biological phytosanitary treatment for strawberry culture: Fortuna variety

Foods from organic farming are becoming more popular. Despite this, the conflicting facts and data on the yield, quality, and cost of organic farming led us to undertake this work, which is focused on the production of organic strawberries. First, we conducted a study on the agronomic outcomes of strawberry production after using a novel line of organic phytosanitary products (ProNutiva). Second, we conducted an economic analysis to assess whether this system would be financially profitable. The experiment focused on the results of two organic farming plots: the “ProNutiva” plot and the control plot. The analysis of the results obtained showed that at the level of the plot treated with “ProNutiva”, the number of mites and aphids was low, as was the number of leaves attacked by the moths. We noted a high leaf-fruit ratio and a good level for quality parameters. The deterioration of the fruits of the ProNutiva plot is slow compared to that of the control plot. Finally, good yields were noted. Indeed, for economic analysis, we noted that organic farming produces 30% lower yields than conventional farming, but it is more profitable with earnings of 19,939.84 US$/ha compared to 7,314.71 US$/ha for conventional farming.

First Report of Anthracnose Caused by Colletotrichum nymphaeae on Strawberry Fruits in Central Argentina.

Strawberry (Fragaria x ananassa) production in Argentina extends to around 1700 hectares. Coronda city, located in Santa Fe province, is an important strawberry producer due to ideal agroecological conditions for culture and a high specialization for production. In November 2021, anthracnose symptoms were observed on strawberries cvs. 'San Andreas' and 'Splendor' in Coronda (31°58'S, 60°55'W), central Argentina. During these years, the incidence of the disease reached 40% of the production. Symptoms included 2-3 mm circular to irregular dark brown spots which enlarged rapidly and became sunken. Under high humidity conditions, concentric rings of pinhead-size salmon-colored acervuli developed on the lesions. The causal agent was isolated by touching acervuli with a sterile needle and monosporic cultures were obtained on PDA after 10 days at 25°C, with a 12-h light period. Colonies were white to gray on the top and orange on the underside, where concentric rings of salmon acervuli were clearly distinguished. The width and length of one hundred conidia were examined in three isolates (CF1, CF2, and CF3), ranging from 3.27 to 5.53 μm (avg.= 4.3 μm), and from 10.37 to 19.52 μm (avg.= 14.27 μm), respectively. The conidia were hyaline, smooth-walled, aseptate, and cylindric-clavate with one end round and one end acute. These morphological characteristics correspond to species belonging to the C. acutatum complex (Damm et al. 2012; Liu et al. 2022). To accurately identify the species, DNA was extracted from isolates, and ß-tubulin (TUB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and histone (HIS3) genes were partially amplified and sequenced (Vieira et al. 2020). TUB2, GAPDH, and HIS3 sequences presented a 100% of identity with species of Colletotrichum nymphaeae. The nucleotide sequences were deposited in GenBank (OR271556-OR271558, TUB2; OR271559-OR271561, GAPDH; and OR271562-OR271564, HIS3). Multilocus phylogenetic analyses performed with reference sequences (Damm et al. 2012) showed that the three isolates clustered with C. nymphaeae, in accordance with BLAST results. To confirm pathogenicity, each isolate was inoculated in eight detached fruits of the cultivar from which it was originally obtained. Two drops of 10 μl of conidial suspension (1x105 conidia per ml) were deposited in non-wounded areas on fruits previously disinfested with 1% sodium hypochlorite solution for 1 min and rinsed twice with sterile distilled water. Drops of sterile water were deposited in eight fruits as control. Pathogenicity tests were repeated twice. Fruits were kept in moist chamber (80+5% relative humidity) at 25°C for ten days. First symptoms appeared 4 days after inoculation. After that, all of the isolates produced symptoms identical to those previously described, whereas the controls remain symptomless. The pathogen was re-isolated from lesions, and identified as C. nymphaeae by morphological characteristics and based on the TUB2 sequences, as previously described. Strawberry anthracnose in Argentina was previously associated with Colletotrichum acutatum, C. gloeosporioides and C. fragariae species based on morphological characteristics (Ramallo et al. 2000; Monaco et al. 2000) but molecular identification was not performed until today. To our knowledge, this is the first report of C. nymphaeae causing anthracnose on strawberry in Argentina. This accurate identification will help to develop more efficient management strategies.

Antibiose de genótipos de morangueiro ao ácaro-rajado

ABSTRACT: The spotted spider mite, Tetranychus urticae (Koch, 1836), is one of the most important pests of strawberry production systems worldwide. Because plant resistance is an important integrated management strategy, the present study investigated the effects of 12 strawberry genotypes on the biological characteristics of this pest under laboratory conditions (25 ± 2 °C and RH 60 ± 10%; 12:12-hour photophase). The experiment was carried using 12 treatments (genotypes), divided into 20 replications each, in a completely randomized design. The response variables were the biological parameters of the spider mite and its survival rate. The development and survival of T. urticae were influenced by different strawberry genotypes. The Camarosa cultivar together with genotypes Selection 05 and 2017-04-03 negatively affected the development and survival of T. urticae. The Selection 02 genotype had greatest susceptibility to the spider mite, which allowed fast development and high survival rate. The reproductive parameters of T. urticae were affected differently as a function of the strawberry genotype, with the Camarosa cultivar and the genotypes Selection 05 and 2017-04-03 being unfavorable to development, suggesting a possible resistance based on antibiosis.

Effect of Mulching Manures and Use of Heterorhabditis Bacteriophora on Strawberry Fruit Yield Temnorhynchus baal and Meloidogyne javanica Under Field Conditions

Abd-Elgawad, M.M.M., L.W. Duncan, M.M.A. Hammam, F. El-Borai and I.E. Shehata. 2024. Effect of Mulching Manures and Use of Heterorhabditis Bacteriophora on Strawberry Fruit Yield Temnorhynchus baal and Meloidogyne javanica Under Field Conditions. Arab Journal of Plant Protection, 42(3): 306-317. https://doi.org/10.22268/AJPP-001262 The importance of safe methods to manage strawberry pests has become more evident with increasing strawberry production and export in Egypt. Root damage by white grubs (Temnorhynchus baal larvae) and root-knot nematode (RKN), Meloidogyne javanica cause severe losses to strawberry fruit yield. Growers often rely on a few selective chemical pesticides to control these pests and to minimize pesticide residues in order to comply with maximum residue limits allowed for fruit export. Entomopathogenic nematodes (EPNs) that invade and kill grubs and reduce RKN population levels in the soil may be as effective as these insecticides in some cases. We evaluated the profitability of mulching strawberry with commonly used cow and/or chicken manure, with and without application of commercial Heterorhabditis bacteriophora in two farms for four consecutive years. All plots received chemical fertilizers. The designed drip irrigation system for EPN delivery in the farms insured efficient and even (P < 0.05) application of EPN in all treatments. Timing of EPN application varied due to import regulatory guidelines. All manure mulch treatments increased strawberry yield each year at a farm in Al-Qalyubia governorate, whereas yield remarkably increased in the fourth season at the farm in El-Beheira governorate. Compared to EPN-treated plots, 70% more (P = 0.06) insects were recovered in soil beneath dead plants in plots that did not receive EPNs. Heterorhabditis bacteriophora boosted fruit yield (P < 0.05) in the second and fourth years at El-Beheira and in all years at Al-Qalyubia. It reduced (P < 0.05) numbers of Meloidogyne javanica galls/egg masses on strawberry roots and juveniles in the soil in both farms. Mulches had no measurable effect on EPN performance, but suppressed pests and boosted plant productivity. The greatest yield enhancement by EPN occurred in the second year at El-Beheira farm when EPNs were applied shortly after planting (October), enabling early season control of the pests, but in the third year at Al-Qalyubia farm where the weather was generally warmer than that at El-Beheira, and therefore more suitable for EPN activity. Keywords: Strawberry yield, entomopathogenic nematodes, Meloidogyne, mulching, Egypt.

Effect of Cultivar and Temperature on Disease Development of Macrophomina Root Rot in Strawberry

Root rot, or charcoal rot, caused by the soilborne fungus Macrophomina phaseolina, is a significant disease affecting strawberry production worldwide. Field trials were conducted for five seasons (2016–2017 to 2020–2021) to evaluate strawberry host plant resistance to Macrophomina root rot (MRR) in California. A wide range of plant resistance to MRR was observed. Because low disease severity occurred in the fifth season, a summary of the first to fourth seasons showed that ‘Osceola’ was highly resistant, whereas ‘Festival’, ‘Sweet Ann’, and ‘Ruby June’ were highly susceptible. Disease severity varied over the seasons for specific cultivars, as did the average final mortality for all cultivars. Models were built to investigate the relationship between environmental variables and final disease mortality among the seasons. Strong positive associations were found between the soil temperature during the first month after planting ( R2 = 0.79, P < 0.0001) or air temperature mid-season ( R2 = 0.79, P < 0.0001) and the final disease mortality of eight cultivars. We concluded that the soil temperature during the early stage of plant development and the mid-season air temperature are important factors in disease development for MRR. Screening new strawberry cultivars and elite breeding lines against MRR should be ongoing as part of a standard process for determining the susceptibility of currently grown and potentially new cultivars.

Optimization of the deficit irrigation management for strawberry production in the Loukkos region

The Moroccan red fruit sector has undergone remarkable development over the last decade, driven by the increase in demand from international markets and promoted by the national agricultural strategy. However, this development calls for the sustainability of water resources, especially in the current context of climate change which makes the future availability of water uncertain. In this sense, deficit irrigation (DI) is one of the promising techniques to improve the efficiency of crop water use. Strawberry is one of the most sensitive red fruits to water deficit. Sufficient and correct irrigation is critical to successful production. Therefore, growers often bring in quantities that exceed the needs of the crop, especially in areas where the cost of water is relatively negligible. In this paper, we studied the response of the two strawberry varieties (Sabrina, Victory) to four water treatments ranging from 50% to 125% of crop evapotranspiration (ETc). The two varieties differed significantly in yield and water consumption, with significant reductions in yield under DI treatments (50%ETc) for Sabrina. However, the fully irrigated treatment (100% ETc), and the DI treatments (75% and 50% ETc) did not show significant differences in yield for Victory.

Evaluation effects of alternative substrates for soilless cultivation of strawberry (Fragaria x ananassa)

Strawberry is one of the major cultivations in Mexico, nonetheless, low development of planting techniques reduces fruit quality. The present research aimed to evaluate alternative substrates for soilless cultivation of strawberry, variety festival (Fragaria x annanasa). Four substrates were evaluated to achieve the goal: T1 coconut fiber substrate, T2 volcanic rock “tezontle”, T3 coconut fiber 50 % volcanic rock “tezontle” 50 %, and T4 soil as control. To compare the substrates, some properties that people chose in the fruit were selected: number of fruits per plant, fruit weight, fruit size, and Brix degrees (° Brix). The ° Brix did not show differences among the treatments; however, under T2 and T3 the best results were observed in terms of the number of fruits per plant, fruit weight and fruit size, which are considered remarkable market fruit qualities. In all the cases, T4 showed the lowest values in comparison to the other substrates. In conclusion, due to its low-cost volcanic rock alone or combined with coconut fiber could be used as a promising substrate for the production of strawberries; however, further work is needed to optimize other factors such as fertilization regimes and irrigation to reduce the production cost in a soilless production system.

Epidemiology and control of strawberry powdery mildew: a review

Strawberry powdery mildew, caused by Podosphaera aphanis, is an economically important disease for strawberry production. Typical symptoms are white mycelium on all aerial parts of affected plants, with young host tissues being the most susceptible. The pathogen overwinters on infected leaves, either as mycelium or chasmothecia, although the quantitative role of chasmothecia in epidemics are not fully understood. In spring, under favourable conditions, the fungus sporulates, disseminating conidia and causing polycyclic infections. The disease is mainly controlled using synthetic fungicides, but there is increasing interest in sustainable alternatives, including microbial biocontrol agents (e.g., Ampelomyces quisqualis, Bacillus spp., Trichoderma spp.) and substances of plant or animal origin (e.g., Equisetum arvense, orange oil, chitosan, whey). Physical methods, (e.g. UV-C, ozone) are also promising alternatives to fungicides. All of these strategies should be combined with appropriate agronomic practices (e.g., overhead irrigation, canopy management) to create unfavourable environments for the pathogen. However, agronomic practices have never been assessed for P. aphanis. Disease forecasting models and DSSs, though available, are underutilized due to their complexity and lack of validation across locations. This review presents the current state of knowledge on P. aphanis the available methods for control of strawberry powdery mildew, and highlights knowledge gaps relating to this host/pathogen relationship.

Control of the whitefly Bemisia tabaci (Genn.) in greenhouses

A formulation based on neem oil (Azadirachta indica), chamomile (Matricaria chamomilla), lechuguilla (Agave lechuguilla torrey) and cactus pectin extracts at different concentrations was used in greenhouses to control the whitefly Bemisia tabaci (Genn.). For moth monitoring, ecological water traps were used to which Noctovi® dipteran pheromones and a food component based on 50% sugar and 20% powdered yeast were added. The work was carried out in six tomato and strawberry production greenhouses located in the city of Durango, in northern Mexico, from August to November 2014. Plant extracts formulated with lechugilla surfactant based on chicalote (Argemone mexicana L.), skunk epazote (Chenopodium glaucum) and higuerilla (Ricinus communis) were used as controls and sprayed at intervals of 15 days each. Field results indicate that the formulation based on neem oil, nopal pectin, chamomile and lechuguilla extracts presented a moth mortality rate of 60% in tomato crops and 62% in strawberry crops.

Effect of Short Day and Low Temperature at the Nursery Stage on the Inflorescence and Yield of Six Different Strawberry (Fragaria ananassa Dutch.) Cultivars in a Soilless Culture System

In Korea, the majority of strawberry cultivation follows a forcing culture, where planting occurs in mid-September after the flower differentiation, and harvesting begins at the end of November. October and November constitute off-season, resulting in higher prices. The accelerated forcing culture involves artificially promoting flower differentiation to expedite strawberry harvest. This study aimed to identify the most suitable schedule for strawberry cultivation using the short-day and low-temperature treatments through greenhouse environmental control during the nursery stage. The selection of the most suitable cultivars for accelerated forcing culture among Korean breeding cultivars (‘Sulhyang’, ‘Kuemsil’, ‘Kingsberry’, ‘Vitaberry’, ‘Jukhyang’, and ‘Altaking’) was also part of the objectives. The nursery treatments were initiated on 4 July, 14 July, and 25 July. After approximately 5 weeks of treatment, transplanting was carried out. The control group was transplanted on 15 September. When night-chilling nursery treatment was applied on 4 July, followed by transplanting on 11 August, all six cultivars exhibited flowering earlier compared to the control group, leading to increased early yield. Particularly, the ‘Sulhyang’ cultivar showed the highest marketable yield at 68.6 g per plant in October. This research contributes to identifying the nursery cultivation schedule for off-season strawberry production and selecting suitable cultivars, and is expected to contribute to increased farm income.

Whole-genome sequencing and comparative genome analysis of Xanthomonas fragariae YM2 causing angular leaf spot disease in strawberry.

Angular leaf spot disease caused by plant pathogenic bacterium Xanthomonas fragariae seriously threatens strawberry crop production globally. In this study, we sequenced the whole genome of X. fragariae YM2, isolated from Yunnan Province, China. In addition, we performed a comparative genome analysis of X. fragariae YM2 with two existing strains of X. fragariae YL19 and SHQP01 isolated from Liaoning and Shanghai, respectively. The results of Nanopore sequencing showed that X. fragariae YM2 comprises one single chromosome with a contig size of 4,263,697 bp, one plasmid contig size of 0.39 Mb, a GC content ratio of 62.27%, and 3,958 predicted coding genes. The genome of YM2 comprises gum, hrp, rpf, and xps gene clusters and lipopolysaccharide (LPS), which are typical virulence factors in Xanthomonas species. By performing a comparative genomic analysis between X. fragariae strains YM2, YL19, and SHQP01, we found that strain YM2 is similar to YL19 and SHQP01 regarding genome size and GC contents. However, there are minor differences in the composition of major virulence factors and homologous gene clusters. Furthermore, the results of collinearity analysis demonstrated that YM2 has lower similarity and longer evolutionary distance with YL19 and SHQP01, but YL19 is more closely related to SHQP01. The availability of this high-quality genetic resource will serve as a basic tool for investigating the biology, molecular pathogenesis, and virulence of X. fragariae YM2. In addition, unraveling the potential vulnerabilities in its genetic makeup will aid in developing more effective disease suppression control measures.

Why does strawberry fruit weight distribution show positive skewness? A simulation model reveals the underlying processes of fruit production

It is widely accepted that the weight distribution of plant fruits conforms to a standard normal distribution. However, some overlooked evidence suggests that some fruits, including strawberries, exhibit positive skewness in fruit weight distribution. This intriguing observation has received limited attention thus far. To shed light on this phenomenon, we conducted a comprehensive simulation study utilizing greenhouse-grown strawberries as our research subject. We modeled the entire process from bee pollination to pollen fertilization on the stigma and fruit growth. The experimental results demonstrated the reliability of the proposed simulation model and revealed that the positive skewness of the fruit weight distribution was the result of the multiplication of several complex intermediate variable distributions, which led to an approximately lognormal distribution. The simulation model and the derived conclusions presented in this paper offer a plausible explanation for the weight distribution patterns observed in strawberry production systems. Furthermore, research results have the potential to be applied to other berry plants that undergo similar bee pollination processes, thereby expanding our understanding of fruit weight distributions across different species.

Comparative characterization and expression analysis revealed cinnamyl alcohol dehydrogenase genes differentially responding to Colletotrichum fructicola in woodland and cultivated strawberries

BACKGROUND: Strawberry (Fragaria×ananassa) production is hampered by anthracnose caused by Colletotrichum spp. Cinnamyl alcohol dehydrogenase (CAD) catalyzes lignin biosynthesis to fortify plant cell wall upon various stresses, but their involvement in strawberry resistance is elusive. OBJECTIVE: Current work aims to uncover the involvement of CAD genes in both woodland and cultivated strawberry responses to Colletotrichum spp. METHODS: Genome-wide identification of CAD genes was updated in cultivated strawberry. Comparative molecular characterization integrated with pathogenesis phenotyping after C. fructicola inoculation, were followed by RT-qPCR analysis and RNAseq data retrieval. RESULTS: Cultivated strawberry comprises 32 CAD genes of three classes. Thirteen syntenic relationships were observed between cultivated and woodland strawberry, with high homology in protein coding regions while promoters being greatly diversified. F. vesca ‘Hawaii4’ was least susceptible, followed by octoploid cultivar ‘ShenQi’, and ‘Benihoppe’ the most susceptible to C. fructicola. The class I CAD4 and CAD5, preferentially expressed in leaves and crowns, respectively, were up-regulated in susceptible varieties at 72 h post inoculation (hpi). Of class II, CAD8 was up-regulated in three genotypes at distinct timepoints, while CAD12 was quickly down-regulated in ‘ShenQi’ upon inoculation. CAD1 and CAD2 of class III were down-regulated in ‘ShenQi’ and ‘Hawaii4’ at distinct stages. The strong involvement of CAD genes in strawberry response to Colletotrichum spp. sets a basis for future functional study. CONCLUSION: F. vesca is less susceptible to Colletotrichum spp. than cultivated strawberries but the expression of CAD family in F. vesca and F.×ananassa were differentially provoked in timing and magnitude hinting no correlation with strawberry resistance to this pathogen.