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Dr. Christopher Menzel
Queensland Department of Agriculture and Fisheries, Brisbane, Australia

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0 Agronomy
0 Horticulture
0 agricultural
0 Plant science
0 Control of fruit size

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Journal article
Published: 23 February 2021 in Horticulturae
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Five strawberry (Fragaria × ananassa Duch.) cultivars were grown in Queensland, Australia to determine whether higher temperatures affect production. Transplants were planted on 29 April and data collected on growth, marketable yield, fruit weight and the incidence of small fruit less than 12 g until 28 October. Additional data were collected on fruit soluble solids content (SSC) and titratable acidity (TA) from 16 September to 28 October. Minimum temperatures were 2 °C to 4 °C higher than the long-term averages from 1965 to 1990. Changes in marketable yield followed a dose-logistic pattern (p < 0.001, R 2s = 0.99). There was a strong negative relationship between fruit weight (marketable) and the average daily mean temperature in the four or seven weeks before harvest from 29 July to 28 October (p < 0.001, R 2s = 0.90). There were no significant relationships between SSC and TA, and temperatures in the eight days before harvest from 16 September to 28 October (p > 0.05). The plants continued to produce a marketable crop towards the end of the season, but the fruit were small and more expensive to harvest. Higher temperatures in the future are likely to affect the economics of strawberry production in subtropical locations.

ACS Style

Christopher Menzel. Higher Temperatures Decrease Fruit Size in Strawberry Growing in the Subtropics. Horticulturae 2021, 7, 34 .

AMA Style

Christopher Menzel. Higher Temperatures Decrease Fruit Size in Strawberry Growing in the Subtropics. Horticulturae. 2021; 7 (2):34.

Chicago/Turabian Style

Christopher Menzel. 2021. "Higher Temperatures Decrease Fruit Size in Strawberry Growing in the Subtropics." Horticulturae 7, no. 2: 34.

Review
Published: 07 September 2020 in The Journal of Horticultural Science and Biotechnology
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Productivity in strawberry (Fragaria × ananassa) can be recorded by measuring marketable or total yield. The first objective of this review was to determine if marketable yield can be predicted from total yield. The second objective of this review was to develop protocols to accurately determine the productivity of strawberry cultivars. Previous research has not examined the relationship between the two measures of productivity and how to best measure the yield of strawberry cultivars. The relationship between marketable and total yield was assessed by examining the performance of strawberry cultivars across 68 studies. Marketable yield had a linear, but inconsistent relationship with total yield across different cultivars, sites and years. The slope from the regression between marketable and total yield ranged from 0.25 to 0.99, with a median of 0.80, and a mean (and SE) of 0.78 ± 0.01. Marketable yield cannot be predicted from total yield. The results of this review demonstrate that marketable yield is a better indicator of productivity than total yield. Both measures of productivity should be used in future cultivar studies. The results also demonstrate that cultivar experiments that include information on the incidence of fruit defects are better than ones that do not.

ACS Style

Christopher Michael Menzel. A review of productivity in strawberries: marketable yield has a linear, but inconsistent relationship with total yield, and cannot be predicted from total yield. The Journal of Horticultural Science and Biotechnology 2020, 96, 135 -144.

AMA Style

Christopher Michael Menzel. A review of productivity in strawberries: marketable yield has a linear, but inconsistent relationship with total yield, and cannot be predicted from total yield. The Journal of Horticultural Science and Biotechnology. 2020; 96 (2):135-144.

Chicago/Turabian Style

Christopher Michael Menzel. 2020. "A review of productivity in strawberries: marketable yield has a linear, but inconsistent relationship with total yield, and cannot be predicted from total yield." The Journal of Horticultural Science and Biotechnology 96, no. 2: 135-144.

Journal article
Published: 09 September 2019 in Agriculture
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Fruit growth in most plants is strongly dependent on photosynthates produced in the leaves. However, if there are too many leaves, the lower part of the canopy becomes heavily shaded and yields are reduced. Experiments were conducted to determine if cultivars of strawberry (Fragaria × ananassa Duch.) grown in Queensland, Australia have excessive leaf production for adequate cropping. Seven cultivars and breeding lines were planted from March to May from 2004 to 2016 and the number of fully-expanded leaves, dry weight of the flowers and fruit, and yield/plant recorded (n = 23). Information was collected on daily maximum and minimum temperatures and solar radiation. Increases in the number of leaves/plant over the season followed a linear pattern (range in R2 from 0.81–0.99), with the relationship generally similar or better than a dose-logistic (sigmoid) function (range in R2 from 0.79–0.99). There were strong linear relationships between the number of leaves/plant and growing degree-days (GDDs), using a base temperature of 7 °C (range in R2 from 0.81–0.99). In contrast, there was no relationship between the number of leaves/plant produced each day and average season daily mean temperature (15.7 °C to 17.8 °C) or radiation (13.0 to 15.9 MJ/m2/day) (R2 < 0.10). Potential yield as indicated by the dry weight of the flowers and immature fruit/plant increased up to 40 to 45 leaves/plant (R2 = 0.49 or 0.50) suggesting that the cultivars do not have excessive leaf production. There was no relationship between yield and the number of leaves/plant (R2 < 0.10) because rain before harvest damaged the fruit in some years. These results suggest that the development of new cultivars with more leaves/plant might increase cropping of strawberries growing in the subtropics.

ACS Style

Christopher M. Menzel. No Evidence of Excessive Leaf Production by Strawberries Grown in the Subtropics. Agriculture 2019, 9, 197 .

AMA Style

Christopher M. Menzel. No Evidence of Excessive Leaf Production by Strawberries Grown in the Subtropics. Agriculture. 2019; 9 (9):197.

Chicago/Turabian Style

Christopher M. Menzel. 2019. "No Evidence of Excessive Leaf Production by Strawberries Grown in the Subtropics." Agriculture 9, no. 9: 197.

Journal article
Published: 18 June 2019 in Agriculture
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Fruit size declines in strawberries (Fragaria × ananassa Duch.) as the season progresses in many subtropical areas, possibly due to inadequate leaf area, over-cropping, or high temperatures. An experiment was conducted to investigate the importance of these factors on fruit growth in ‘Festival’ in Queensland, Australia. Groups of plants were defoliated to remove half of the mature leaves on each plant, thinned to remove all the inflorescences on each plant, or defoliated and thinned. Control plants were left intact. Defoliation, thinning, or defoliation + thinning decreased yield (total and/or marketable) by 15% to 24% compared with the control. Defoliation, or defoliation + thinning decreased average fruit weight (total and/or marketable fruit) by 1 to 2 g compared with the control, whereas thinning had the opposite effect. The incidence of small fruit increased towards the end of the season. There were strong relationships between fruit weight and average daily mean temperature in the seven weeks before harvest (R2s greater than 0.80). Fruit weight decreased from 24 g to 8 g as the temperature increased from 16 °C to 20 °C. This response was not affected by defoliation or thinning. The strong effect of temperature on fruit size indicates a problem for production in the future in the absence of heat-tolerant cultivars.

ACS Style

Christopher M. Menzel. Temperature Has a Greater Effect on Fruit Growth than Defoliation or Fruit Thinning in Strawberries in the Subtropics. Agriculture 2019, 9, 127 .

AMA Style

Christopher M. Menzel. Temperature Has a Greater Effect on Fruit Growth than Defoliation or Fruit Thinning in Strawberries in the Subtropics. Agriculture. 2019; 9 (6):127.

Chicago/Turabian Style

Christopher M. Menzel. 2019. "Temperature Has a Greater Effect on Fruit Growth than Defoliation or Fruit Thinning in Strawberries in the Subtropics." Agriculture 9, no. 6: 127.

Journal article
Published: 10 August 2018 in Agriculture
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Optimum leaf nitrogen (N) concentrations have been identified for strawberry (Fragaria ×ananassa Duch.) in temperate and Mediterranean areas, but whether these values are appropriate for the subtropics is unclear. Two experiments were conducted for 2 years to determine if the seasonal changes in the concentration of leaf N affect the diagnosis of deficiency or sufficiency of strawberry plants in Queensland, Australia. In 2014, ‘Festival’, ‘Fortuna’, and ‘Winter Dawn’ were planted in early April and grown with and without N for the entire season. Then, ‘Festival’ was planted the following year in mid- or late April and, again, was grown with and without N. Yield was slightly lower with N in 2014, but higher with it the following year, particularly in the early planting. The concentration of total N in young, fully expanded leaves decreased from 3.0% to 2.0% as leaf, crown, and root dry weight increased, while the concentration of nitrate-N (NO3-N) decreased from 1200–3200 to 50–500 mg/kg. These changes in leaf N were large enough to affect the diagnosis of N deficiency or sufficiency. The concentration of leaf N was less variable than the concentration of leaf NO3-N and, therefore, better for estimating the nutrient status of strawberry plants in the subtropics.

ACS Style

Christopher M. Menzel. Changes in the Concentration of Leaf Nitrogen over the Season Affect the Diagnosis of Deficiency or Sufficiency in Strawberries in the Subtropics. Agriculture 2018, 8, 126 .

AMA Style

Christopher M. Menzel. Changes in the Concentration of Leaf Nitrogen over the Season Affect the Diagnosis of Deficiency or Sufficiency in Strawberries in the Subtropics. Agriculture. 2018; 8 (8):126.

Chicago/Turabian Style

Christopher M. Menzel. 2018. "Changes in the Concentration of Leaf Nitrogen over the Season Affect the Diagnosis of Deficiency or Sufficiency in Strawberries in the Subtropics." Agriculture 8, no. 8: 126.

Original paper
Published: 26 September 2016 in Australasian Plant Pathology
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The effect of different fungicide programs on grey mould (caused by Botrytis cinerea) and stem-end rot (caused by Gnomoniopsis fructicola) affecting strawberry plants (Fragaria ×ananassa cv. Festival) was studied in subtropical Australia over three years. The treatments involved a range of different synthetic multi- and single-site fungicides with different modes of action, a plant-defence promoter, plant extracts (lupin and rhubarb), organic acids, fatty acids, a salt, two strains of Bacillus subtilis, and single strains of B. amyloliquefaciens, Streptomyces lydicus and Trichoderma harzianum. Standard programs based on captan and thiram alternated, and applied with iprodione, fenhexamid, cyprodinil + fludioxonil, and penthiopyrad resulted in 3–4 % of unmarketable fruit compared with 25–38 % in the water-treated controls. There was no difference in the level of disease suppression when five or thirteen applications of single-site fungicides were rotated with the two multi-site fungicides. The incidence of unmarketable fruit was similar to the standard programs using isopyrazam (in 1 year out of 2), or penthiopyrad, fluazinam, chlorothalonil or thiram alone (in 1 year out of 1). The other fungicide programs were generally less effective. There were strong relationships between marketable yield and the incidence of unmarketable fruit over the three years (R2s = 0.82–0.93). A strategy based on thiram and captan applied alternately, with reduced applications of single-site fungicides is recommended and should reduce the chance of resistance to single-site fungicides becoming widespread in populations of the grey mould fungus. Although the program based on thiram alone had a similar incidence of unmarketable fruit as the standard program, repeated weekly applications of thiram are not recommended as they may cause unacceptable residues in the fruit. There were issues with some of the other fungicides due to phytotoxicity, residues, or difficulties with registering new fungicides that are in the same chemical group as currently registered products.

ACS Style

Christopher Michael Menzel; Apollo Gomez; Lindsay Alistair Smith. Control of grey mould and stem-end rot in strawberry plants growing in a subtropical environment. Australasian Plant Pathology 2016, 45, 489 -498.

AMA Style

Christopher Michael Menzel, Apollo Gomez, Lindsay Alistair Smith. Control of grey mould and stem-end rot in strawberry plants growing in a subtropical environment. Australasian Plant Pathology. 2016; 45 (5):489-498.

Chicago/Turabian Style

Christopher Michael Menzel; Apollo Gomez; Lindsay Alistair Smith. 2016. "Control of grey mould and stem-end rot in strawberry plants growing in a subtropical environment." Australasian Plant Pathology 45, no. 5: 489-498.

Journal article
Published: 01 June 2014 in HortTechnology
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The effect of plastic high tunnels on the performance of two strawberry (Fragaria ×ananassa) cultivars (Festival and Rubygem) and two breeding lines was studied in southeastern Queensland, Australia, over 2 years. Production in this area is affected by rain, with direct damage to the fruit and the development of fruit disease before harvest. The main objective of the study was to determine whether plants growing under tunnels had less rain damage, a lower incidence of disease, and higher yields than plants growing outdoors. Plants growing under the tunnels or outdoors had at best only small differences in leaf, crown, root, and flower and immature fruit dry weight. These responses were associated with relatively similar temperatures and relative humidities in the two growing environments. Marketable yields were 38% higher under the tunnels compared with yields outdoors in year 1, and 24% higher in year 2, mainly due to less rain damage. There were only small differences in the incidences of grey mold (Botrytis cinerea) and small and misshaped fruit in the plants growing under the tunnels and outdoors. There were also only small differences in postharvest quality, total soluble solids, and titratable acidity between the two environments. These results highlight the potential of plastic high tunnels for strawberry plants growing in subtropical areas that receive significant rainfall during the production season.

ACS Style

Christopher M. Menzel; Lindsay A. Smith; Jenny A. Moisander. The Productivity of Strawberry Plants Growing Under Plastic High Tunnels in a Wet Subtropical Environment. HortTechnology 2014, 24, 334 -342.

AMA Style

Christopher M. Menzel, Lindsay A. Smith, Jenny A. Moisander. The Productivity of Strawberry Plants Growing Under Plastic High Tunnels in a Wet Subtropical Environment. HortTechnology. 2014; 24 (3):334-342.

Chicago/Turabian Style

Christopher M. Menzel; Lindsay A. Smith; Jenny A. Moisander. 2014. "The Productivity of Strawberry Plants Growing Under Plastic High Tunnels in a Wet Subtropical Environment." HortTechnology 24, no. 3: 334-342.

Journal article
Published: 07 June 2013 in Scientia Horticulturae
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We investigated the effect of hedging on the yield of ‘Kwai May Pink’ litchi (Litchi chinensis Sonn.) trees over 4 years at three sites in eastern Australia. Individual trees in these orchards were pruned at various times to remove 0.5–1.0 m of the terminal branches. At Brooklet in northern New South Wales, at the southern end of the commercial range of the crop, the optimum time of pruning appeared to be in early- to mid-February, but this was before the previous crop was harvested. Trees hedged in early March had virtually no crop since most of the branches did not complete a flush of growth before the normal time of floral initiation in winter. In Bundaberg in southern Queensland, this was not an issue, and good yields followed hedging in late February or early March in 3 out of 3 years. In Mareeba in northern Queensland at the northern end of the commercial range, hedging in mid-March was highly variable, with good yields in 1 out of 4 years and poor yields in 3 out of 4 years. The optimum time of pruning appeared to be in early January or early March in this area, which would allow the completion of two or one growth flushes before winter. There is the added problem in this environment that the trees may not flower every year because the warmer conditions provide only a short window for floral initiation. Trees at Bundaberg and Mareeba hedged in May or June just before the normal time of floral initiation flowered but cropped poorly compared with control trees. The results of this study confirm the strong relationship between flowering and shoot development in litchi. They also support the idea that the developing fruit are dependent on current photosynthates produced by the leaves behind the inflorescences. Suggestions are provided on options for pruning litchi trees growing in different environments, including warm tropical areas, warm subtropical areas, and cool subtropical areas.

ACS Style

Trevor Olesen; Christopher M. Menzel; Cameron A. McConchie; Neil Wiltshire. Pruning to control tree size, flowering and production of litchi. Scientia Horticulturae 2013, 156, 93 -98.

AMA Style

Trevor Olesen, Christopher M. Menzel, Cameron A. McConchie, Neil Wiltshire. Pruning to control tree size, flowering and production of litchi. Scientia Horticulturae. 2013; 156 ():93-98.

Chicago/Turabian Style

Trevor Olesen; Christopher M. Menzel; Cameron A. McConchie; Neil Wiltshire. 2013. "Pruning to control tree size, flowering and production of litchi." Scientia Horticulturae 156, no. : 93-98.

Journal article
Published: 01 June 2012 in HortTechnology
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The effect of time of planting and plant size on the performance of ‘Festival’ and ‘Florida Fortuna’ strawberry (Fragaria ×ananassa) plants was studied at Nambour in southeastern Queensland, Australia, over 2 years. The main objective of the work was to determine whether small plants yielded proportionally less than large plants as planting was delayed. First, bare-rooted transplants of ‘Festival’ were divided into small (crown diameters ranging from 6 to 10 mm) or large plants (10 to 17 mm) and planted in late March, mid-April, or late April. Second, transplants of ‘Florida Fortuna’ were divided into small (5 to 8 mm) or large plants (8 to 17 mm) and planted in early April, mid-April, or early May. The early planting for each cultivar corresponded with the time that the transplants are first available from commercial strawberry nurseries. Yields were generally greater in plants planted in late March/early April compared with plants planted later. Differences in yield between the small and large plants were consistent across the different times of planting, with the small plants always having lower yields. Small transplants are an issue for the productivity of strawberry fields in this environment whether they are planted early or late. Producers should consider paying a premium for large transplants delivered early in the season.

ACS Style

Christopher M. Menzel; Lindsay Smith. Effect of Time of Planting and Plant Size on the Productivity of ‘Festival’ and ‘Florida Fortuna’ Strawberry Plants in a Subtropical Environment. HortTechnology 2012, 22, 330 -337.

AMA Style

Christopher M. Menzel, Lindsay Smith. Effect of Time of Planting and Plant Size on the Productivity of ‘Festival’ and ‘Florida Fortuna’ Strawberry Plants in a Subtropical Environment. HortTechnology. 2012; 22 (3):330-337.

Chicago/Turabian Style

Christopher M. Menzel; Lindsay Smith. 2012. "Effect of Time of Planting and Plant Size on the Productivity of ‘Festival’ and ‘Florida Fortuna’ Strawberry Plants in a Subtropical Environment." HortTechnology 22, no. 3: 330-337.