Earliness and fruit yield and quality of annual-fruiting red raspberry (Rubus idaeus L.): Effects of temperature and genotype
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Journal of Horticultural Science & Biotechnology (2010) 85 (4) 341–349
Earliness and fruit yield and quality of annual-fruiting red raspberry
(Rubus idaeus L.): Effects of temperature and genotype
By A. SØNSTEBY1* and O. M. HEIDE2
1Arable Crops Division, Norwegian Institute for Agricultural and Environmental Research,
NO-2849 Kapp, Norway
2Department of Ecology and Natural Resource Management, Norwegian University of Life
Sciences, P.O. Box 5003, NO-1432 Ås, Norway
(e-mail: anita.sonsteby@bioforsk.no) (Accepted 12 March 2010)
SUMMARY
Earliness, fruit yield and quality of six annual-fruiting raspberry (Rubus idaeus L.) cultivars were tested under protected
cultivation in a cool Nordic environment. After raising plants for 5 weeks in greenhouses with average mean
temperatures of 20°C, 22°C, or 26°C, the plants were cropped in an open plastic tunnel at latitude 61°N. The highest
yielding cultivars were ‘Autumn Bliss’ and ‘Polka’, with 640 g plant–1. Overall, the most promising cultivar was ‘Polka’
which combined high yield with large fruit of good flavour and firmness. In earliness, ‘Polka’ was surpassed only by
‘Autumn Bliss’, which confirmed its position as the earliest commercial annual-fruiting cultivar. However, ‘Autumn Bliss’
had soft fruits with little flavour and a short shelf-life, which greatly reduced the potential of the cultivar for the fresh
fruit market. The later ripening cultivar ‘Erika’ did not complete its crop under these conditions, but its large unrealised
yield potential and good fruit quality rendered it extremely promising for environments with a longer growing season.
‘Sugana’ was late, with low yields and poor fruit quality, while ‘Marcela’ did not yield enough fruit to be of interest under
the present conditions. High temperatures during the 5-week raising period generally advanced flowering and fruit
ripening in all cultivars, with the notable exception of ‘Autumn Treasure’ in which flowering was suppressed and strongly
delayed by high temperature. Under the present conditions, there was a highly positive correlation between earliness and
fruit yield. Regression analyses identified a low number of dormant buds as the single most important component of
plant architecture associated with high fruit yield, accounting for 47% of the total variation.
T wo groups of red raspberry (Rubus idaeus L.)
cultivars with different life cycles are commonly
recognised. In addition to the traditional biennial-
(Williams, 1960; Sønsteby and Heide, 2008), the annual-
fruiting cultivars flower freely at temperatures as high as
approx. 27°C (Lockshin and Elfving, 1981; Carew et al.,
fruiting cultivars, in which flowering and fruiting of the 2003) and even at 30°C (Sønsteby and Heide, 2009).
shoots (canes) take 2 years, we have the annual-fruiting While Carew et al. (2003) found no consistent effect of
cultivars (also referred to as Autumn-fruiting or photoperiod on flowering in ‘Autumn Bliss’, flowering
primocane-fruiting cultivars), in which shoot growth, was consistently and significantly advanced and
flowering and fruiting are completed in a single growing enhanced by long-days (LD) in cv. Polka (Sønsteby and
season (Hudson, 1959; Keep, 1988). The breeding history Heide, 2009). Accordingly, the annual-fruiting cultivars
of this latter group, which has involved crosses with other can initiate flowers even in the middle of the Summer,
Rubus species such as R. arcticus, R. odoratus, R. while in biennial cultivars floral initiation is restricted to
spectabilis and others, has been reviewed by Keep the cool temperatures and SD conditions of Autumn.
(1988). In addition, a third, intermediate, so-called tip- In annual-fruiting raspberries, floral initiation starts at
flowering type is sometimes considered (Carew et al., the tip and then spreads basipetally (Sønsteby and
2000; 2003; Dale, 2008). Such cultivars usually produce a Heide, 2009). The process may continue down the full
few flowers and fruits at the tip of the shoot at the end of length of the cane, or may terminate after a given
the first growing season, while the remainder of the buds number of nodes. Nevertheless, only a variable number
will flower and fruit in the second year. However, this of buds at the upper part of the cane will grow out, with
type of behaviour can be found in both annual- and the remaining buds becoming dormant. While it has been
biennial-fruiting cultivars (Williams, 1960; Carew et al., considered that these lower buds need SD for floral
2000) and, as demonstrated by Sønsteby and Heide initiation (e.g., Ourecky, 1976; Dale, 2008), dissections
(2009), it is a plastic trait that, to a large extent, is under revealed that these buds also initiated flowers under LD
environmental control (cf. Slate, 1940; Ourecky, 1976). and high temperature conditions, but required chilling to
Physiologically, the annual- and biennial-fruiting break dormancy and therefore become biennial
cultivars are rather different. While the biennial-fruiting (Sønsteby and Heide, 2009). The distinctive physiological
cultivars are short-day (SD) plants that require characteristics of annual-fruiting cultivars are, therefore,
temperatures below 15°C for the initiation of flowers the ability to initiate flower buds during mid-Summer
and the absence of dormancy in a certain proportion of
*Author for correspondence. the initiated floral buds, leading to flowering in the first342 Earliness and yield in annual-fruiting raspberry cultivars
year. In ‘Polka’, it was demonstrated that the number and
30
proportion of annual-flowering buds increased with
increasing temperature, being much greater at 24°C than 1
25
at 12°C and 18°C (Sønsteby and Heide, 2009).
2
Although annual-fruiting raspberry cultivars have
Temperature (°C)
20
been known and grown in both Europe and America for 3
more than 200 years (Keep, 1988), so far they have failed
to obtain a dominant position in the commercial 15
raspberry industry. Late maturation and inadequate fruit
quality have been the main reasons for this. However, the 10
introduction of new and better-adapted cultivars with
improved fruit quality (Danek, 2002; Jennings, 2002; 5
2008; Pitsioudis et al., 2007), together with an increasing
emphasis on protected cultivation and extension of the 0
raspberry marketing season, have created a new and 19/5 24/5 29/5 3/6 8/6 13/6 18/6 23/6
Date
growing interest in annual-fruiting cultivars as a
component in year-round raspberry production (Oliveira FIG. 1
Time-courses of actual daily mean temperatures recorded in the three
et al., 2002; Dale et al., 2003). Therefore, we have greenhouses during the 5-week plant-raising period.
compared the yield performance and fruit quality of one
older and five recently released European annual-
fruiting cultivars under tunnel conditions in a cool point temperatures in the greenhouses were 15°C, 20°C
Nordic climate. Bearing in mind the highly diverse and 25°C, respectively, with venting set-points 1°C
genetic background of annual-fruiting raspberries higher. Actual temperatures in the greenhouses and in
(Keep, 1988), we have also studied the influence of the plastic tunnel were recorded every 10 min and stored
temperature on flowering and on the cropping on a Super Link 4 datalogger (Senmatic A/S, Søndersø,
performance of these cultivars by varying the Denmark). As shown in Figure 1, the temperature
temperature during the early half of growth (the raising control in the greenhouses was not satisfactory, with
period). overlapping temperatures in the two cooler houses
during periods of hot weather resulting in total average
temperatures of 20.1°C, 21.7°C and 26.0°C in the three
MATERIALS AND METHODS greenhouses during the 5-week “raising” period (later
Plant material and cultivation referred to as 20°C, 22°C and 26°C). Daily maximum,
The annual-fruiting red raspberry (Rubus idaeus L.) minimum, and mean temperatures in the Haygrove
cultivars ‘Autumn Bliss’, ‘Autumn Treasure’, ‘Erika’, tunnel are presented in Figure 2. At a height of approx.
‘Marcela’, ‘Polka’, and ‘Sugana’ were propagated from 20 cm, the plants were transplanted singly into 3.5 l pots,
adventitious root buds as described by Sønsteby and and again, at the time of transfer to the tunnel, into 7.5 l
Heide (2009). ‘Autumn Bliss’, which was released from pots where they remained until the experiment was
East Malling, UK in 1983 (Keep et al., 1984), has been the terminated. At all stages, a coarse-textured sphagnum
standard annual-fruiting raspberry cultivar grown in peat growth medium (Veksttoro; Jorostrøfabrikk,
Central and Northern Europe for many years (Finn et al., Degernes, Norway) with a pH of 5.8 was used. In the
2008). It is early-maturing, healthy, and of relatively short Haygrove tunnel, the plants were placed in rows on a
stature, but bearing soft fruits with little flavour has ground cover of black Mypex plastic with an inter-row
limited its popularity. It has been widely used in breeding spacing of 2 m, with four plants per running metre within
programmes (Keep, 1988) and is a parent of all the other
cultivars tested here. ‘Autumn Treasure’ is a more recent,
35
spine-free release from the East Malling breeding
programme (Meiosis Ltd., 2009), while ‘Polka’ is a Polish 30
cultivar derived from ‘Autumn Bliss’ (Danek, 2002),
which has now taken over as the most widely grown 25
Max.
annual-fruiting cultivar in Central and Northern Europe
Temperature (°C)
20
(Finn et al., 2008). The Italian-bred ‘Erika’ and the Swiss
‘Sugana’ are both recent selections from crosses between 15 Mean
‘Autumn Bliss’ and the biennial-fruiting ‘Tulameen’
Min.
(Pitsioudis et al., 2007), while ‘Marcela’ (selection 941/3) 10
is a cross between ‘Autumn Bliss’ and ‘Joan Squire’
5
(Jennings, 2002; 2008). Due to limited plant availability,
‘Marcela’ was restricted to only one raising temperature. 0
The entire experiment was carried out at the Apelsvoll
Experimental Station in the central part of South -5
24/6 5/7 15/7 25/7 4/8 14/8 24/8 3/9 13/9 23/9 3/10
Norway (60°70’N, 10°87’E; 250 m asl). The plants were
Date
raised in three heated greenhouses under natural LD
conditions (approx. 17 – 19 h) for 5 weeks (from 19 May FIG. 2
Time-courses of the daily maximum, minimum, and mean temperatures
to 23 June 2009), then transferred to an open Haygrove in the plastic Haygrove tunnel during flowering and fruiting of all the
plastic tunnel for flowering and fruiting. The heating set- raspberry plants.A. SØNSTEBY and O. M. HEIDE 343
the rows. Only one shoot per pot was allowed to grow, TABLE I
Plant height and the percentage of plants with visible flower buds in six
with all additional shoots being removed by repeated annual-fruiting raspberry cultivars after raising for 5 weeks at three
pruning. The plants were supported by fixing to plastic- different temperatures
coated steel wire trellises and fertilised by daily Plants with
fertigation with a complete fertiliser solution as Cultivar Temperature (°C) Cane height (cm) flower buds (%)
described by Sønsteby et al. (2009). Plant protection was ‘Autumn Bliss’ 20 71.3 73.3
provided by biological control methods only. 22 85.4 73.3
26 114.1 80.0
Mean 90.3 bc* 75.6 a
Experimental design, data observation and analysis ‘Autumn Treasure’ 20 71.3 60.0
At the time of transfer to the tunnel, evenly-sized 22 104.3 0.0
26 111.5 0.0
plants, approx. 10 cm-tall, were selected and arranged in Mean 95.7 b 20.0 bc
a split-plot design with three replicate blocks each ‘Polka’ 20 57.5 53.3
consisting of five plants of each cultivar in each 22 98.6 100.0
temperature treatment. Shoot height and the presence of 26 96.7 80.0
Mean 83.6 cd 76.7 a
flower buds were recorded at this stage. Berries were
‘Erika’ 20 73.9 40.0
harvested two-to-three times per week from week-31 to 22 123.9 40.0
week-41, and the numbers and weights of berries were 26 127.4 20.0
Mean 108.4 a 33.3 b
recorded. Fruit taste quality (flavour), firmness, and total
‘Sugana’ 20 47.7 0.0
appearance were assessed twice, at weeks-37 and -39, by 22 92.1 0.0
an inexperienced twelve-member test panel and scored 26 101.0 13.3
according to a scale from 1 to 9, with 5 as the acceptable Mean 80.3 d 4.4 c
limit. At the end of the harvest season, the numbers of ‘Marcela’ 22 46.1 8.3
flowers and unripe fruits remaining on each plant were Probability levels of significance by ANOVA
Source of variation
recorded, and the fruiting shoot architecture was Temperature (A) < 0.001 n.s.
registered by recording the final shoot height, number of Cultivar (B) < 0.001 < 0.001
dormant buds and fruiting laterals, as well as the length AB < 0.001 < 0.001
of each lateral on all plants. *Mean values within the same column followed by different lower-case
letters indicate a significant difference (P < 0.05) between cultivars
Data were subjected to analysis of variance (ANOVA) (n = 15).
and regression analysis was by standard procedures The data are the means of three replicates, each with five plants of each
using the MiniTab® Statistical Software programme cultivar for each temperature treatment.
package (Release 14; Minitab Inc., State College, PA,
USA). ‘Marcela’ was excluded from these analyses strongly delayed by high temperature in ‘Autumn
because of the lack of orthogonal data for this cultivar, Treasure’ and, to a lesser extent, in ‘Erika’ (Table I;
but a separate analysis of the 22°C data only, was Table II; Figure 3). Total yields were highest in ‘Autumn
conducted for comparison of all cultivars. Bliss’ and ‘Polka’, which had significantly higher yields
than ‘Erika’ and ‘Autumn Treasure’, which again out-
yielded ‘Marcela’ and ‘Sugana’ (Table II). However,
RESULTS because of a highly significant interaction (P < 0.001) of
Shoot height at the end of the 5-week “raising” period cultivar and temperature, the main effect of
was increased significantly (P < 0.001) by increasing temperature on fruit yield was not significant. A large
temperature, and varied significantly (P < 0.001) among number of flowers and fruits did not reach maturity
the cultivars (Table I). ‘Erika’ plants were the tallest and before harvest was terminated by low tunnel
most vigorous, while those of ‘Marcela’ were the temperatures. This was especially so with ‘Erika’ and, to
smallest. Flower bud appearance was generally advanced a lesser extent, in ‘Polka’ plants raised at low
by increasing temperature, with the notable exception of temperature and in ‘Autumn Treasure’ plants raised at
‘Autumn Treasure’ in which bud appearance was earliest high temperature (Table II). The total number of fruits
at low temperature. This resulted in a highly significant and flowers per plant, being a measure of yield
cultivar temperature interaction which rendered the potential, varied significantly (P < 0.001) among the
main effect of temperature non-significant (Table I). cultivars, being highest in ‘Erika’ and ‘Polka’ (Table II).
Time-courses of the weekly fruit harvests for the six Whereas the number of harvested fruits generally
cultivars are shown in Figure 3. The earliest maturing increased with increasing “raising” temperature, the
cultivar was ‘Autumn Bliss’, with the first pick on opposite trend was observed in ‘Autumn Treasure’, again
August 2 (week-31), followed by ‘Polka’ and ‘Erika’, demonstrating the inhibitory effect of high pre-flowering
‘Autumn Treasure’ and ‘Marcela’, and finally ‘Sugana’, temperature on flowering and fruiting of this cultivar
2, 3, and 4 weeks later, respectively. ‘Autumn Bliss’ also (Table II). While the main effect of temperature was
had the earliest 50% harvest, followed by ‘Polka’; significant at P = 0.03, both the cultivar effect and the
whereas ‘Erika’ had a late harvest peak, despite a interaction with temperature were highly significant (P <
relatively early first pick (Table II). The effect of the 0.001). Berry size varied significantly (P < 0.001) among
“raising” temperature varied markedly among the the cultivars, but was satisfactory throughout harvest in
cultivars, resulting in a highly significant interaction all cultivars (Figure 4). ‘Sugana’ had the largest fruit,
(P < 0.001) of cultivar and temperature on both followed by ‘Erika’ and ‘Polka’, while ‘Autumn Bliss’ and
earliness and total yield (Table II). Whereas flowering ‘Marcela’ had the smallest fruits (Table II). High
and fruit maturation were generally advanced by high temperature during the “raising” period consistently and
temperature in most cultivars, both processes were significantly (P = 0.006) reduced berry weight, although344 Earliness and yield in annual-fruiting raspberry cultivars
150 150
'Autumn Bliss' 'Autumn Treasure'
125 20°C 125 20°C
Weekly harvest (g/plant)
22°C 22°C
Avling (g/plante)
100 26°C 100 26°C
75 75
50 50
25 25
A B
0 0
150 31 32 33 34 35 36 37 38 39 40 41 150 31 32 33 34 35 36 37 38 39 40 41
'Polka' Tid (uke nr.) 'Erika' Tid (uke nr.)
125 20°C 125 20°C
Weekly harvest (g/plant)
22°C 22°C
Avling (g/plante)
100 26°C 100 26°C
75 75
50 50
25 25
C D
0 0
150 31 32 33 34 35 36 37 38 39 40 41150 31 32 33 34 35 36 37 38 39 40 41
'Sugana' E 'Marcela' F
Tid (uke nr.) Time (week no.)
125 20°C 125 22°C
Weekly harvest (g/plant)
22°C
Avling (g/plante)
100 26°C 100
75 75
50 50
25 25
0 0
31 32 33 34 35 36 37 38 39 40 41 31 32 33 34 35 36 37 38 39 40 41
Time (week no.) Time (week no.)
FIG. 3
Time-courses of the weekly fruit harvests of the six annual-fruiting raspberry cultivars (Panels A–F). Each datum point represents the mean weekly
–1
harvest in g plant for three replicates with five plants of each cultivar for each of the three “raising” temperature treatments.A. SØNSTEBY and O. M. HEIDE 345
TABLE II
Days-to-50% harvest, fruit yield, and flowering and fruiting components of six annual-fruiting raspberry cultivars raised for 5 weeks under three
different temperatures
No. of Flowers and Total no of Fruits
Temperature Days to Fruit yield harvested Fruit weight fruits not fruits and and flowers
Cultivar (°C) 50% harvest* (g plant–1) fruits (g) harvested flowers per lateral
‘Autumn Bliss’ 20 73.7 572.3 101.0 6.0 228.0 329.4 19.8
22 74.3 642.5 112.5 5.7 255.7 368.0 21.0
26 75.0 713.9 136.7 5.1 269.0 405.1 21.6
Mean 74.3 a** 642.9 a 116.7 a 5.6 c 250.9 c 367.5 c 20.8 bc
‘Autumn Treasure’ 20 82.3 467.5 82.6 5.9 157.0 239.4 15.9
22 84.0 363.5 68.2 5.7 173.0 241.0 15.3
26 100.7 28.0 5.1 5.6 456.0 461.4 22.1
Mean 89.0 c 286.3 c 52.0 b 5.8 c 262.0 c 313.9 c 18.2 cd
‘Polka’ 20 86.3 595.5 85.4 7.6 599.0 684.3 32.3
22 79.0 664.0 101.0 6.9 465.0 565.5 26.8
26 81.0 655.7 104.6 6.5 353.0 457.3 20.2
Mean 82.1 b 638.4 a 97.0 a 7.0 b 477.0 b 569.0 b 26.5 ab
‘Erika’ 20 82.7 400.2 57.5 7.5 623.0 680.5 29.7
22 87.3 543.8 76.8 7.5 566.0 642.6 25.6
26 90.7 502.0 81.0 6.5 928.0 1009.1 32.6
Mean 86.9 c 482.0 b 71.8 b 7.2 ab 706.0 a 777.4 a 29.5 a
‘Sugana’ 20 94.0 42.6 5.7 8.0 222.0 228.1 13.0
22 93.3 140.5 16.0 8.0 200.0 215.7 12.5
26 94.7 248.2 36.3 6.8 190.0 235.2 12.9
Mean 94.0 d 143.8 d 19.3 c 7.6 a 204.0 c 226.3 c 12.8 d
‘Marcela’ 22 84.0 231.3 42.7 5.6 384.0 426.3 24.7
Probability levels of significance by ANOVA
Source of variation
Temperature (A) 0.03 n.s. 0.03 0.006 n.s. n.s. n.s.
Cultivar (B) < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001
AB < 0.001 < 0.001 < 0.001 n.s. 0.004 0.009 0.04
*Days from transfer to the tunnel.
**Mean values within the same column followed by different lower-case letters indicate a significant difference (P < 0.05) between cultivars (n = 15).
All data are the means of three replicates, each with five plants of each cultivar for each “raising” temperature treatment.
the effect diminished in successive harvests (Figure 4). brighter colours. ‘Erika’, which also had good flavour and
Fruit quality and attractiveness varied significantly firmness, had a brighter red colour. ‘Autumn Treasure
among the cultivars (P < 0.001), with ‘Autumn Bliss’ and and ‘Marcela’ also had acceptable quality (Table III). A
‘Sugana’ achieving the lowest scores, and ‘Polka’ and special feature of ‘Autumn Treasure’ was a tendency to
‘Erika’ the highest (Table III). None of the quality produce fruit with split receptacles (branched fruit), a
attributes were significantly affected by the “raising” feature which has been reported previously for the
temperature, probably because of the long intervening related cultivar, ‘Autumn Byrd’ (Knight, 2002).
period before fruit ripening. On the other hand, all Growth vigour and final cane height varied highly
quality scores were significantly higher in the first than in significantly (P < 0.001) among the cultivars. ‘Erika’ and
the second test. ‘Autumn Bliss’ scored poorly on both ‘Sugana’ had the tallest canes, and ‘Marcela’ had the
flavour and firmness and, due to poor skin strength, the shortest ones; while ’Polka’ and ‘Autumn Bliss’ were
fruits quickly became juicy with a short shelf-life. ‘Polka’ intermediate (Table IV). Final cane height increased
fruit had a glossy appearance that made them extremely significantly (P < 0.01) with increasing “raising”
attractive, and this cultivar received quality scores, temperature, except in ‘Sugana’, which exhibited the
comparable to the biennial-fruiting ‘Glen Ample’. opposite trend, thus creating a highly significant (P <
However, a relatively dark fruit colour may make it less 0.001) interaction of temperature cultivar. This was
attractive for certain markets with a preference for paralleled by closely similar effects on leaf (node)
TABLE III
Fruit quality evaluation in six annual-fruiting raspberry cultivars as assessed by a 12-member test panel on two occasions during the harvest period†
Taste quality Firmness Fruit appearance
Date of testing Date of testing Date of testing
Cultivar 10/9 21/9 Mean 10/9 21/9 Mean 10/9 21/9 Mean
‘Autumn Bliss’ 3.8 3.5 3.6 c* 4.8 3.3 4.0 c 4.3 3.7 4.0 d
‘Autumn Treasure’ 5.1 5.3 5.2 b 6.4 5.5 6.0 ab 5.5 5.0 5.3 bc
‘Polka’ 6.4 5.9 6.2 a 6.9 6.2 6.5 a 6.8 5.9 6.3 a
‘Erika’ 6.5 5.0 5.7 ab 6.7 5.1 5.9 ab 6.8 5.1 6.0 ab
‘Sugana’ 4.1 4.0 4.0 c 4.3 5.0 4.7 c 4.6 4.3 4.4 cd
‘Marcela’ 5.3 4.9 5.1 b 5.9 5.3 5.6 b 5.5 5.2 5.3 b
Probability levels of significance (ANOVA)
Source of variation
Cultivar (A) < 0.001 < 0.001 < 0.001
Date (B) 0.03 < 0.001 < 0.001
AB n.s. 0.008 n.s.
*Mean values within the same column followed by different lower-case letters indicate a significant difference (P < 0.05) between cultivars (n = 12).
n.s., not significant.
The data are the means of all “raising” temperatures, each value represents the mean of 12 individual assessments.
†
Quality attributes were scored on a scale from 1 to 9, in which 9 was best and 5 was considered acceptable.346 Earliness and yield in annual-fruiting raspberry cultivars
10 10
'Autumn Bliss' 'Autumn Treasure'
9 9
8 8
7 7
Berry size (g/berry)
Berry size (g/berry)
6 6
5 5
4 4
3 3
20°C 20°C
2 2 22°C
22°C
1 26°C A 1 26°C B
0 0
10 H1 H4 H7 H10 H13 H16 H19 H22 H2510 H1 H4 H7 H10 H13 H16 H19 H22 H25
'Polka' 'Erika'
9 Time (harvest no.) 9 Time (harvest no.)
8 8
7 7
Berry size (g/berry)
Berry size (g/berry)
6 6
5 5
4 4
3 3
20°C 20°C
2 22°C 2 22°C
1 26°C 1 26°C
C D
0 0
10 H1 H4 H7 H10 H13 H16 H19 H22 H2510 H1 H4 H7 H10 H13 H16 H19 H22 H25
'Sugana' Time (harvest no.) Time (harvest no.) 'Marcela'
9 9
8 8
7 7
Berry size (g/berry)
Berry size (g/berry)
6 6
5 5
4 4
3 3
20°C
2 22°C 2 22°C
1 26°C 1
E F
0 0
H1 H4 H7 H10 H13 H16 H19 H22 H25 H1 H4 H7 H10 H13 H16 H19 H22 H25
Time (harvest no.) Time (harvest no.)
FIG. 4
Time-courses of fruit weight during the harvest period in six annual-fruiting raspberry cultivars. Each datum point represents the mean fruit weight
for each harvest based on three replicates with five plants of each cultivar for each of the three “raising” temperature treatments.A. SØNSTEBY and O. M. HEIDE 347
TABLE IV
Plant architectural characteristics of five annual-fruiting raspberry cultivars as influenced by temperature during a 5-week raising period
Final cane Total number No. of No. of Percentage flowering Mean lateral
Cultivar Temperature (°C) height (cm) of nodes fruiting nodes dormant nodes laterals length (cm)
‘Autumn Bliss’ 20 134.4 30.5 16.6 13.8 57.1 31.9
22 139.3 30.8 17.7 13.0 57.4 32.4
26 144.3 31.7 18.8 12.4 59.6 34.6
Mean 139.3 bc* 31.0 c 17.7 c 13.1 c 58.0 c 33.0 b
‘Autumn Treasure’ 20 113.4 32.3 15.0 16.4 46.6 30.9
22 163.3 41.3 15.8 25.1 38.5 22.9
26 184.1 52.8 20.9 29.8 39.1 42.9
Mean 153.6 b 42.1 a 17.2 c 23.8 a 41.4 d 32.3 b
‘Polka’ 20 123.7 28.4 21.2 8.6 71.3 47.7
22 138.4 30.7 21.1 8.9 69.5 51.1
26 142.9 33.7 22.7 10.8 67.7 47.8
Mean 134.6 c 30.8 c 21.6 b 9.4 d 69.6 a 48.8 a
‘Erika’ 20 177.7 40.2 22.9 16.7 57.0 44.6
22 195.4 40.0 25.1 14.9 62.5 50.1
26 198.1 43.8 31.0 10.2 70.9 60.9
Mean 190.4 a 41.3 ab 26.3 a 13.2 c 63.5 b 51.9 a
‘Sugana’ 20 184.6 40.8 17.6 23.2 43.2 29.7
22 186.6 38.3 17.2 20.8 45.1 28.5
26 165.4 37.9 17.5 18.6 46.6 27.4
Mean 179.3 a 39.0 b 17.4 c 21.0 b 44.9 d 28.5 b
‘Marcela’ 22 100.0 25.3 17.3 7.9 68.6 39.1
Probability levels of significance by ANOVA
Source of variation
Temperature (A) 0.006 0.003 0.02 n.s. n.s. n.s.
Cultivar (B) < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001
AB < 0.001 < 0.001 0.01 < 0.001 0.005 0.05
*Mean values within the same column followed by different lower-case letters indicate a significant difference (P < 0.05) between cultivars (n = 15).
n.s., not significant.
All data are the means of three replicates, each with five plants of each cultivar for each “raising” temperature treatment.
numbers. The cultivars ‘Erika’ and ‘Sugana’, with commercial annual-fruiting raspberry cultivar, with
inherently late flowering, formed many nodes at all ‘Polka’ 1 week behind, whereas ‘Sugana’ was particularly
temperatures, whereas the early flowering ‘Polka’ and late (Figure 3; Table II). Despite a relatively early first
‘Autumn Bliss’ had relatively low node numbers across pick, ‘Erika’ had a late harvest peak, and failed to
the range of “raising” temperatures. Because of the complete its crop before harvest was terminated by
suppression of flowering at high pre-flowering freezing temperatures. Under the present conditions,
temperature, ‘Autumn Treasure’ had a marked increase there was a close correlation between early maturation
in node numbers as the temperature was increased from and fruit yield. Thus, a Pearson correlation analysis
20°C to 26°C (Table IV). The many and long laterals of revealed a highly significant (P < 0.001) negative
‘Erika’, with an armoury of numerous sharp spines, made correlation between yield and days-to-50%-harvest
the picking operation of this cultivar a rather unpleasant across all cultivars and temperature treatments (r =
exercise, especially compared with the spine-free –0.758; N = 48). We have not tested any of the many
‘Autumn Treasure’. American annual-fruiting cultivars; but, according to
The percentage of flowering and fruiting nodes (i.e., Keep (1988) and Jennings (1988), even a relatively early
non-dormant buds), which is a measure of annual- cultivar such as ‘Heritage’ failed to complete its crop in
fruiting strength, varied significantly (P < 0.001) among South-East England. Apparently, the American cultivars
cultivars (Table IV). It was particularly high in ‘Erika’ are of little interest for the cool Nordic climate. These
and ‘Polka’, while it was low in the lower-yielding results confirm the previous findings of Carew et al.
‘Sugana’ and in ‘Autumn Treasure’ plants raised at high (2003) and Sønsteby and Heide (2009) with ‘Autumn
temperature. The proportion of fruiting laterals was also Bliss’ and ‘Polka’, respectively, that flowering and fruit
relatively high in ‘Marcela’, thus compensating, to some maturation are generally advanced by a high “raising”
extent, for the short canes with low node numbers in this temperature in annual-fruiting raspberries. A notable
cultivar. A stepwise regression analysis involving fruit exception was ‘Autumn Treasure’, in which flowering was
yield vs. the plant architecture components listed in suppressed and strongly delayed by high pre-flowering
Table IV, identified the number of dormant buds as the temperature. Thus, the number of harvested fruit per
single most important component, accounting for 47% of plant was reduced from 82 to 5 (Table II), while the
the yield variation across all cultivars and “raising” number of nodes produced before flowering was
temperature treatments (r = –0.692; P < 0.001). increased from 32 to 53 when the “raising” temperature
was increased from 20°C to 26°C in this cultivar (Table
IV). Also, while the highest fruit yields were obtained in
DISCUSSION plants raised at the intermediate and/or high
These results demonstrate a significant variation in temperature in the other cultivars, the earliest and
earliness, temperature responses, and fruit yields and highest yields were obtained in ‘Autumn Treasure’ plants
quality among the six cultivars tested. ‘Autumn Bliss’ raised at 20°C. This has important implications for the
confirmed its position as the earliest maturing cultivation of this cultivar which should not be raised at348 Earliness and yield in annual-fruiting raspberry cultivars
temperatures above 20°C for its full yield potential to be exception to this principle. In a previous paper (Sønsteby
realised. This cool temperature requirement may be and Heide, 2009), we demonstrated that the magnitude
related to the introgression of R. arcticus genes into the of flowering in ‘Polka’ was, to a large extent, determined
pedigree of this cultivar (Keep, 1988; Knight, 2002). by the balance between dormant and actively growing
The highest harvested yields were obtained in buds. The present experiments, using more cultivars,
‘Autumn Bliss’ and ‘Polka’, with approx. 640 g plant–1, confirm and extend this relationship to hold true also for
corresponding to more than 12 tonnes ha–1 in our fruit yield (Table II; Table IV). Thus, a low number of
planting system (Table II). However, the large dormant buds was identified as the single most
unrealised yield potential of ‘Erika’, together with its important plant architectural trait associated with high
good fruit quality, made this cultivar promising for yields. This trait alone accounted for 47% of the total
environments with a longer growing season. Acceptable variation across all cultivars and “raising” temperature
yields were also obtained with ‘Autumn Treasure’, when treatments. In the high yielding ‘Polka’ and ‘Autumn
raised at 20°C (Table II), and it is possible that even Bliss’, the numbers of fruiting and dormant nodes were
lower “raising” temperatures would have been optimal only slightly influenced by raising temperature within
for this cultivar. Fruit size, which was acceptable in all the present range, indicating stable high yields and a
cultivars throughout the harvest, was particularly large relatively wide environmental adaptability. In contrast, in
in ‘Sugana’, ‘Erika’, and ‘Polka’. Interestingly, low ‘Erika’, the number and percentage of fruiting nodes
temperature during the raising period consistently (laterals) increased markedly with increasing
increased fruit weight, although the effect diminished in temperature, thus underlining the preference for a high
successive harvests (Table II; Figure 4). Fruit quality was “raising” temperature in this cultivar. Since flowering
highly acceptable in ‘Polka’ and ‘Erica’, both of which spreads basipetally (cf. Sønsteby and Heide, 2009),
scored well on both flavour and firmness, as well as on flowering and fruiting were delayed in laterals situated at
general performance (Table III). Also ‘Autumn the base of the cane. This was obviously the basis for the
Treasure’ and ‘Marcela’ had acceptable fruit quality, sustained and relatively late maturation of ‘Erika’ plants
whereas the fruits of ‘Autumn Bliss’ and ‘Sugana’ were (Figure 3) which, in particular, had many and long
of inferior quality with little flavour, weak skins, and a laterals (Table IV).
short shelf-life. In conclusion, these results confirm that flowering and
Vegetative growth vigour was greatest in ‘Erika’ and fruiting in annual-fruiting raspberry are promoted by
‘Sugana’, which reached final cane heights of almost 2.0 high “raising” temperature with an optimum in the low-
m, whereas ‘Marcela’ had a notably short stature with the to-mid 20°C range. A notable exception was ‘Autumn
potential for self-supporting cultivation and mechanical Treasure’ in which flowering was suppressed by “raising”
harvesting (Table IV). Also ‘Polka’ and ‘Autumn Bliss’, temperatures above 20°C. ‘Polka’ was identified as the
with their early flowering and fruiting, had relatively most promising annual-fruiting raspberry cultivar for the
short canes. Cane height generally increased with cool Nordic environment. A low proportion of dormant
increasing temperature during the raising period, an buds were identified as the most important structural
effect that was particularly pronounced in ‘Autumn trait associated with high yield. Under the conditions
Treasure’ due to its greatly delayed flowering at high tested here, there was a highly positive correlation
“raising” temperature. between earliness and yield.
Productivity in raspberry is mainly a function of the
number of laterals produced per cane, and the number We gratefully acknowledge financial support for this
and weight of fruits per lateral (cf. Ourecky, 1967; Keep, work from A/S Gartnerhallen and the Research Council
1988; Sønsteby et al., 2009). The present results of Norway. We also thank Ms. U. Myrheim and Mr. H.G.
demonstrate that annual-fruiting cultivars represent no Espelien for excellent technical assistance.
REFERENCES
CAREW, J. G., GILLESPIE ,T., WHITE, J., WAINSWRIGHT, H., BRENNAN, HUDSON, J. P. (1959). Effects of environment on Rubus idaeus L. I.
R. and BATTEY, N. H. (2000). The control of the annual growth Morphology and development of the raspberry plant. Journal
cycle in raspberry. Journal of Horticultural Science & of Horticultural Science, 34, 163–169.
Biotechnology, 75, 495–503. JENNINGS, D. L. (1988). Raspberries and Blackberries: Their
CAREW, J. G., MAHMOOOD, K., DARBY, J., HADLEY, P. and BATTEY, Breeding, Diseases and Growth. Academic Press, London, UK.
N. H. (2003). The effect of temperature, photosynthetic photon 230 pp.
flux density, and photoperiod on the vegetative growth and JENNINGS, D. L. (2002). Breeding primocane-fruiting raspberries at
flowering of ‘Autumn Bliss’ raspberry. Journal of the American Medway Fruits – progress and prospects. Acta Horticulturae,
Society for Horticultural Science, 128, 291–296. 585, 85–89.
DALE, A. (2008). Raspberry production in greenhouses: JENNINGS, D. (2008). Autumn-fruiting raspberries: keeping up with
Physiological aspects. Acta Horticulturae, 777, 219–223. the Joans. Fruit Forum. http://www.fruitforum.net/autumn-fruit-
DALE, A., KING, E. M. and SAMPLE, A. (2003). Scheduling primo- ing-raspberries-keeping-up-with-the-jo.htm.
cane fruiting raspberries for year-round production in green- KEEP, E. (1988). Primocane (autumn)-fruiting raspberries: a review
houses. Acta Horticulturae, 626, 219-223. with particular reference to progress in breeding. Journal of
DANEK, J. (2002). ‘Polka’ and ‘Procusa’ – New primocane fruiting Horticultural Science, 63, 1–18.
raspberry cultivars from Poland. Acta Horticulturae, 585, KEEP, E., PARKER, J. H. and KNIGHT, V. H. (1984). ‘Autumn Bliss’, a
197–198. new early autumn-fruiting raspberry. Report of East Malling
FINN, C. E., MOORE, P. P. and KEMPLER, C. (2008). Raspberry Research Station for 1983. 191–192.
cultivars: What’s new? What’s succeeding? Where are breeding KNIGHT, V. H. (2002). Raspberry breeding at HRI-East Malling.
programs headed? Acta Horticulturae, 777, 33–37. Acta Horticulturae, 585, 57–61.A. SØNSTEBY and O. M. HEIDE 349
LOCKSHIN, L. S. and ELFVING, D. C. (1981). Flowering responses of SLATE, G. L. (1940). Breeding autumn-fruiting raspberries. Proceedings
Heritage red raspberry to temperature and nitrogen. of the American Society for Horticultural Science, 37, 574–578.
HortScience, 16, 527–528. SØNSTEBY, A. and HEIDE, O. M. (2008). Environmental control of
MEIOSIS Ltd. (2009). Breeder’s description ‘Autumn Treasure’. growth and flowering of Rubus idaeus L. cv. Glen Ample.
(http://www.meiosis.co.uk/fruit/autumn_treasure.htm). Scientia Horticulturae, 117, 249–256.
OLIVEIRA, P. B., LOPES-DA-FONSECA, L. and MONTEIRO, A. A. SØNSTEBY, A. and HEIDE, O. M. (2009). Effects of photoperiod and
(2002). Combining different growing techniques for all year temperature on growth and flowering in the annual (primo-
round red raspberry production in Portugal. Acta Horticulturae, cane) fruiting raspberry (Rubus idaeus L.) cultivar Polka.
585, 545–553. Journal of Horticultural Science & Biotechnology, 84, 439–446.
OURECKY, D. K. (1976). Fall-bearing red raspberries, their future SØNSTEBY, A., MYRHEIM, U., HEIBERG, N. and HEIDE, O. M. (2009).
and potential. Acta Horticulturae, 60, 135–144. Production of high yielding red raspberry long canes in a
PITSIOUDIS, A., ODEURS, W. and MEESTERS, P. (2007). New Northern climate. Scientia Horticulturae, 121, 286–297.
primocane raspberries ‘Erika’ and ‘Sugana’. COST863 SGM on WILLIAMS, I. H. (1960). Effects of environment on Rubus idaeus L.
Small Fruit Production Systems. 9-10. (http://www.euroberry.it/ V. Dormancy and flowering of the mature shoot. Journal of
documents/wgm07/Programa%20e%20resumos.pdf). Horticultural Science, 35, 214–220.You can also read
