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23a) many times higher level of informational redundancy of miRNA-mediated transcription control realizing through NF-kB p50 TFBS versus c-myc TFBS; this suggest c-myc to be much more evolutionary old than NF-KB;
b) significantly higher level of informational redundancy of miRNA-mediated transcription control in Homo sapients than in the rodents.
References
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7. Orlovsky O.A., Samoylenko O.A., Shlyakhovenko V.O. Transcription factor binding sites in a structural gene: what may be this? (by the example of the genes encoding the main enzymes of the polyamines metabolism) // East Eur. Sci. J. - 2016.- No 6(10), Part 3.- P. 62-68.
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do 2000/7-1-0-113
Paulouski M.B.
PhD in Biology
Central Botanical Gardens of the National Academy of Sciences of Belarus
Павловский Николай Болеславович
кандидат биологических наук, заведующий лабораторией Центральный ботанический сад Национальной академии наук Беларуси
PHENOLOGICAL DEVELOPMENT OF HIGHBUSH BLUEBERRY VARIOUS CULTIVARS IN
BELARUS
Summary: Drawing on a decade of stationary observation of seasonal growth rhythms and development, the paper demonstrates peculiarities of phenological development stages in 20 highbush blueberry cultivars and 3 halfhighbush blueberry cultivars. The calendar periods for the beginning of vegetation and duration of the spring phenological development stages in the cultivars differ considerably from year to year and depend on weather conditions. Cultivar differences in the development of blueberry show more vividly in the blooming period, and especially at the fruit ripening stage. The climatic conditions in the central agro-climatic region of Belarus ensure the completion of the entire cycle of seasonal development in highbush blueberry cultivars of the entire crop ripening range.
Key words: Vaccinium corymbosum, Highbush blueberry; Cultivars; Phenology; Temperature conditions; Correlation; Belarus.
Аннотация: На основании данных десятилетних стационарных наблюдений за ритмами сезонного роста и развития показаны особенности прохождения фаз фенологического развития 20 сортов голубики высокорослой и 3 сортов голубики полувысокорослой. Календарные сроки начала вегетации и продолжительность весенних фаз фенологического развития сортов по годам значительно варьируют и зависят от погодных условий. Сортовые различия развития голубики проявляются существенней в сроках цветения, а особенно созревания плодов. На основании результатов корреляционного анализа показаны особенности термической зависимости фенологического развития сортов голубики высокорослой в течение вегетационного периода. У подавляющего числа сортов голубики установлена сильная положительная корреляция между урожайностью и продолжительностью периода созревания плодов. Климатические условия центральной агроклиматической области Беларуси обеспечивают прохождение полного цикла сезонного развития сортами голубики высокорослой всего спектра созревания урожая.
Ключевые слова: Vaccinium corymbosum, голубика высокорослая, сорта, фенология, температурные условия, корреляция, Беларусь.
Introduction
Highbush blueberry (Vaccinium corymbosum) is a relatively new small-fruit crop introduced in Belarus from the Atlantic coast of North America. There are no absolutely identical regions in terms of climatic and soil
conditions. Therefore, plants are normally transferred to conditions that differ from their places of origin and their introduction can be successful when alien crops possess phenotypic adaptive flexibility. In order to identify the applicability of a plant in new conditions,
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direct experience is required, N. Vavilov said [1]. The primary criterion to assess the success of the introduction is to analyze the correspondence of seasonal development rhythms to the climatic conditions of a new region. The knowledge of the timeline for a cultivar to pass phenological development stages is also necessary to schedule agronomic arrangements and properly site various cultivars.
In recent years, phenological development of highbush blueberry has been analyzed in neighboring countries — Latvia [2, 3], Poland [4], in Ukrainian forest steppes [5], Central Black Earth Region of Russia [6, 7], and the Moscow Region [8]. In Belarus, seasonal development rhythms of blueberry cultivars were studied by Kurlovich [9] (5 cultivars) and Rupasova et al. [10] (3 cultivars). Despite the substantial number of literary sources about the phenological development of blueberry, most of the available information is either fragmentary or generalized.
The objective of this paper is to assess the correspondence of the endogenous rhythms of the introduced blueberry cultivars to the climatic conditions of Belarus and identify the impact of biotic and abiotic factors on their phenological development indicators.
Material and methods
Phenological observations were performed from 2006 to 2015 at the collection plantations of the Experimental Station of the Central Botanical Gardens of the National Academy of Sciences of Belarus located in the central agro-climatic region of the country in the Gantsevichy District of the Brest Region (N 52°74', E 26°38'). The objects of the study included fruit-bearing plants of 20 highbush blueberry cultivars, namely 'Bluecrop', 'Blueray', 'Bluerose', 'Bluetta', 'Caro-linablue', 'Coville', 'Croatan', 'Darrow', 'Denise Blue', 'Duke', 'Earliblue', 'Elizabeth', 'Hardyblue', 'Herbert', 'Jersey', 'Nelson', 'Patriot', 'Reka', 'Rubel', 'Weymouth' and 3 half-highbush blueberry cultivars -'Northblue', 'Northcountry', and 'Northland'. Blueberry plantations were established in 1999 on mineral soils with the use of two-year transplants. Sandy soils were used with underlying loose inequigranular sand with pH (H2O) equal to 4.5. The planting pattern is 2.0x1.5 m. In dry-weather periods, the plants were watered with overhead irrigation.
Observations of seasonal development rhythms were held on a daily basis employing the procedure developed by I. Yurkevich et al. [11] and in compliance with recommendations by the University of Michigan [12]. Calendar times of the commencement of the following phenological stages and corresponding sums of
positive air temperatures were registered: swelling of buds, breaking of buds, beginning and end of growth, flower-bud formation, blooming, fruit ripening, autumn leaf color, and leaf fall.
Blueberry shoots were classified into three types based on M. Mazurenko's practical guidelines [13]. The first type includes 'formation shoots' that perform the skeletal function, have enhanced growth properties, are normally 50 cm to 100 cm long and 6 mm to 8 mm in diameter, and grow from the base of the bush. The second type includes 'replacement shoots' that grow at an acute angle in the upper part of formation shoots after the dieback of terminal buds, are from 30 cm to 50 cm long and 4 mm to 6 mm in diameter. The third type, 'branching (fruiting) shoots', are the most numerous, grow almost at a right angle on replacement shoots, branching shoots, and, more rarely, formation shoots, are from 5 cm to 20 cm long and 1.5 mm to 2.5 mm in diameter.
The time interval from the stable transition of air temperatures to above 0°C in spring to below 0°C in autumn was considered the vegetation period. Its duration in the years of observation varied from 212 to 274 days, with sums of positive temperatures from 2,910°C to 3,288°C. Weather conditions were reported based on data provided by the Gantsevichi weather station. Data were processed with the use of the Microsoft Excel Analysis ToolPak at a 95% confidence interval. For statistical processing calendar dates were translated into a continuous numerical row [11]. To determine the correlation between the time of the commencement of seasonal development stages and ambient temperatures, the study used the average daily temperature for a period of ten days prior to the beginning of a phenological stage. When determining the correlation between the duration of a seasonal development stage and air temperatures, the average daily temperature for a pheno-logical stage was calculated.
Results and discussion
Generative development. Highbush blueberry vegetation begins with the swelling of reproductive buds. Swollen buds increase in their volume, cover scales spread, and light-green stripes emerge. Flower buds swell on average at the end of March in the halfhighbush blueberry cultivars 'Northblue' and 'North-country' (26.03) (Table 1). In highbush blueberry cultivars reproductive buds swell in 3 to 7 days. During seasons with late vegetation periods and warm spells (2012, 2013), flower buds swell at about the same time in all blueberry cultivars.
Table 1
The average date of the passage of the main phases of phenological development of cultivars of blueberries __in the central agro-climatic region of Belarus (2006-2015)_
Cultivar Development phase
bud swell bud break late green tip leaf emergence early pink bud early bloom
Bluecrop 31.03±7 19.04±9 29.04±6 4.05±5 7.05±6 16.05±5
Blueray 30.03±8 18.04±7 27.04±5 4.05±5 9.05±3 18.05±3
Bluerose 1.04±7 17.04±8 26.04±6 2.05±4 6.05±5 19.05±5
Bluetta 30.03±7 18.04±7 27.04±5 2.05±5 3.05±5 11.05±5
Carolinablue 1.04±7 18.04±8 27.04±7 3.05±5 8.05±6 19.05±5
Coville 1.04±6 19.04±8 27.04±7 4.05±5 6.05±6 17.05±4
Croatan 1.04±9 17.04±9 26.04±6 2.05±4 3.05±7 11.05±4
Darrow 1.04±7 18.04±9 27.04±7 3.05±5 5.05±6 17.05±4
Denise Blue 1.04±8 17.04±8 26.04±4 2.05±4 5.05±7 14.05±7
Duke 30.03±7 17.04±8 26.04±6 2.05±4 4.05±6 13.05±4
Earliblue 30.03±8 19.04±8 27.04±5 4.05±5 8.05±5 14.05±4
Elizabeth 2.04±6 19.04±9 27.04±7 3.05±5 8.05±5 19.05±4
Hardyblue 29.03±9 17.04±8 26.04±7 2.05±5 4.05±5 12.05±3
Herbert 30.03±8 18.04±7 28.04±5 5.05±5 10.05±4 19.05±5
Jersey 1.04±7 18.04±7 27.04±7 4.05±5 7.05±5 20.05±4
Nelson 1.04±7 19.04±9 27.04±7 3.05±5 6.05±5 17.05±3
Northblue 26.03±8 13.04±8 23.04±6 1.05±5 30.04±4 10.05±4
Northcoun-try 26.03±8 11.04±8 23.04±6 29.04±4 30.04±5 7.05±4
Northland 30.03±8 19.04±8 27.04±5 4.05±5 7.05±4 14.05±3
Patriot 29.03±7 12.04±7 24.04±6 1.05±4 1.05±4 10.05±4
Reka 31.03±7 18.04±7 26.04±6 2.05±4 4.05±3 14.05±3
Rubel 30.03±8 21.04±8 28.04±5 6.05±5 10.05±3 19.05±4
Weymouth 30.03±7 16.04±7 27.04±5 5.05±5 5.05±3 12.05±4
LSDo.o5 12.3 9.4 7.5 6.3 6.0 4.7
Table 1
Continued
Cultivar Development phase
petal fall beginning of ripening end of ripening leaf coloring beginning of leaf fall
Bluecrop 4.06±4 15.07±5 6.08±8 25.09±8 5.10±6
Blueray 7.06±6 21.07±7 20.08±7 26.09±11 12.10±4
Bluerose 4.06±4 23.07±8 4.09±6 23.09±4 10.10±7
Bluetta 31.05±5 3.07±5 3.08±3 15.09±9 7.10±6
Carolinablue 5.06±6 24.07±7 6.09±11 23.09±4 7.10±6
Coville 5.06±4 22.07±4 15.09±6 20.09±4 6.10±5
Croatan 31.05±3 7.07±4 10.08±5 17.09±3 30.09±5
Darrow 6.06±4 18.07±4 10.09±9 21.09±4 5.10±6
Denise Blue 3.06±2 12.07±3 21.08±6 22.09±5 29.09±4
Duke 8.06±9 5.07±4 10.08±7 12.09±5 27.09±4
Earliblue 3.06±6 8.07±5 3.08±4 21.09±10 4.10±6
Elizabeth 8.06±5 25.07±8 21.09±7 19.09±6 2.10±3
Hardyblue 2.06±4 13.07±5 15.08±7 19.09±3 27.09±5
Herbert 5.06±6 1.08±6 1.09±10 28.09±8 11.10±7
Jersey 9.06±5 21.07±5 6.09±9 20.09±2 2.10±5
Nelson 6.06±4 18.07±5 3.09±6 18.09±2 3.10±4
Northblue 1.06±5 6.07±4 14.08±13 17.09±4 30.09±5
Northcountry 29.05±5 7.07±4 10.08±8 19.09±3 27.09±5
Northland 30.05±4 13.07±4 3.08±6 25.09±9 10.10±5
Patriot 29.05±4 7.07±5 12.08±6 19.09±8 27.09±4
Reka 3.06±5 5.07±5 9.08±12 20.09±3 30.09±4
Rubel 6.06±5 29.07±7 5.09±8 3.10±4 10.10±6
Weymouth 31.05±5 6.07±4 11.08±7 22.09±5 7.10±7
LSDo.o5 6.6 6.7 10.2 7.62 7.50
Calendar periods of the commencement of vegetation in blueberry cultivars vary significantly depending on the year. In 2013, reproductive buds increased in volume in mid-April, whereas in 2008 and 2014, flower buds swelled and began shooting in winter (February); however, when cold spells followed, their development halted, and they remained in that state until more favorable weather conditions set. This complicated the exact identification of the time of the commencement of vegetation. Reproductive buds in other berry plants notably
swell in Belarus during thaws as well, including Sam-bucus, Lonkera, and Ríbes mgrum [14].
The average daily temperature during the swelling of flower buds is 4.7° C (Table 2), and the average sum remains between 67°C and 96°C (Table 3). This correlates with the data previously obtained by T. Kurlovich [9] in the same region — 26°C-109°C. According to Zh. Rupasova et al. [10], highbush blueberry buds in the Central agro-climatic region of Belarus swell in temperatures ranging from 108° C and 142° C.
Table 2
The average air temperature in the decade of the beginning of the passage of the main phases of phenologi-
Year Development phase
bud swell bud break late green tip leaf emergence early pink bud early bloom beginning of ripening leaf coloring beginnin g of leaf fall
2006 6.1 9.7 9.7 13.7 12.7 13.4 19.3 12.9 12.3
2007 5.9 8.3 8.4 8.0 8.0 12.5 16.0 11.8 12.3
2008 4.7 2.6 9.3 12.0 12.0 11.5 17.0 9.4 9.8
2009 3.1 8.4 10.5 10.5 12.8 11.1 19.5 8.8 8.7
2010 7.1 8.8 8.0 10.2 12.3 15.2 24.1 10.8 4.6
2011 3.0 8.0 12.4 10.5 12.9 14.9 20.6 14.6 13.4
2012 4.7 9.3 14.6 14.6 14.6 16.9 23.7 14.0 11.3
2013 4.8 9.4 11.8 14.2 14.2 17.2 19.2 14.4 7.2
2014 3.2 7.2 8.2 8.2 8.2 12.9 19.1 13.8 11.2
2015 4.3 5.1 11.3 11.3 11.7 12.0 17.9 7.3 5.8
Average 4.7± 0.9 7.7±1.5 10.0±1.0 11.3±1.6 11.9±1.5 13.8±1.5 19.6±1.7 12.0±2.0 9.7±2.0
Table 3
Average amount of positive daily mean air temperature during the passage of the main phases of phenological develop_ment of varieties of blueberries in the central agro-climatic region of Belarus (2006-2015),°C_
Cultivar Development phase
bud swell bud break late green tip leaf emergence early pink bud early bloom
Bluecrop 85±27 226±60 313±41 405±34 446±48 547±42
Blueray 83±22 216±38 320±38 405±13 463±33 589±37
Bluerose 90±26 198±47 294±70 355±51 427±67 587±54
Bluetta 82±23 214±46 316±47 402±16 417±30 499±25
Carolinablue 91±27 202±50 304±63 362±55 444±73 577±52
Coville 95±28 214±56 308±76 370±61 416±71 558±56
Croatan 83±28 194±50 286±65 350±52 382±64 482±45
Darrow 92±27 208±53 300±75 366±61 408±66 579±41
Denise Blue 86±24 190±41 216±43 318±57 416±66 569±59
Duke 80±28 199±52 288±67 367±42 403±55 522±30
Earliblue 78±23 227±58 315±43 403±15 448±42 533±44
Elizabeth 96±28 221±57 296±70 360±55 443±76 589±66
Hardyblue 80±25 197±46 279±70 348±55 395±68 498±48
Herbert 91±32 211±42 319±49 387±43 456±68 574±72
Jersey 94±30 209±53 303±72 369±57 426±67 597±48
Nelson 95±28 196±45 285±77 366±42 435±59 575±33
Northblue 70±18 160±41 261±64 332±63 358±61 466±54
Northcountry 67±20 150±36 251±62 313±57 365±73 444±51
Northland 81±22 226±58 314±41 400±17 460±37 537±23
Patriot 72±23 163±31 263±60 335±57 351±65 462±49
Reka 87±33 202±53 289±64 353±51 383±65 517±51
Rubel 83±22 206±41 301±50 386±22 468±56 584±47
Weymouth 75±16 201±37 300±49 386±22 441±43 512±24
LSD0.05 33.5 63.1 49.6 32.3 79.2 62.3
Table 3 Continued
Cultivar Development phase
petal fall beginning of ripening end of ripening leaf coloring beginning of leaf fall
Bluecrop 830±63 1576±81 2110±113 2790±106 2946±99
Blueray 891±66 1720±120 2242±121 2864±96 2991±81
Bluerose 893±73 1733±82 2527±158 2763±130 2969±102
Bluetta 780±50 1412±51 1988±68 2677±182 2961±81
Carolinablue 896±67 1767±102 2549±185 2813±126 2944±101
Coville 885±69 1736±82 2691±170 2777±114 2911±95
Croatan 802±65 1499±92 2109±71 2723±136 2996±67
Darrow 895±69 1695±71 2627±181 2776±87 2929±98
Denise Blue 833±67 1576±75 2294±160 2758±102 2906±118
Duke 859±49 1445±85 2109±75 2659±152 2894±113
Earliblue 834±44 1503±80 2000±73 2797±111 2963±83
Elizabeth 909±71 1776±123 2726±156 2750±108 2903±91
Hardyblue 807±61 1560±83 2201±102 2775±107 2862±119
Herbert 871±66 1922±105 2440±123 2813±158 2976±72
Jersey 924±60 1736±95 2525±151 2780±109 2902±85
Nelson 904±48 1711±100 2510±124 2763±100 2937±99
Northblue 781±60 1468±78 2152±152 2739±115 2891±111
Northcountry 754±71 1443±68 2090±106 2745±126 2885±102
Northland 773±43 1571±62 1943±56 2835±112 2963±105
Patriot 746±50 1437±79 2140±121 2729±129 2860±104
Reka 824±50 1457±83 2060±148 2758±120 2886±132
Rubel 874±81 1677±149 2338±200 2871±96 3011±70
Weymouth 760±21 1434±53 2010±87 2795±97 2943±88
LSDo.o5 79.8 151.1 174.7 157.9 128.28
In mid-April, 16 to 22 days after the swelling of flower buds, these buds shoot virtually in the same cultivar order as bud swelling. In another 7 to 12 days, shoots begin growing, after which the first leaves appear in 6 to 9 days. Flower-bud formation begins almost at the same time as the first leaves during the first ten days of May. Flower buds are often formed 2 to 5 days after the first leaves appear. In some years with late spring and sudden warming (2006, 2013), flower-bud formation begins 2 or 3 days before the first leaves appear.
Blueberry blooming normally starts by mid-May, on the 10th day after flower buds form. Half-highbush blueberry cultivars are the first to flower — 'North-country' (7.05), 'Northblue' (10.05) and highbush 'Patriot' (10.05). They are followed by 'Bluetta', 'Croatan' (11.05), 'Hardyblue', 'Weymouth' (12.05), 'Duke' (13.04), 'Denise Blue', 'Earliblue', 'Northland' and 'Reka' (14.05). 'Jersey' is the last to flower (20.05). Depending on the cultivar, the sum of the average daily air temperatures depending on the cultivar varies from 444° C to 597° C, and the daily air temperature averages 13.8° C. The blooming stage lasts from 16 ('Northland') to 22 ('Northblue', 'Northcountiy') days (Table 4) depending on the cultivar.
Blueberry flowers are gathered in a drooping raceme and open at various times, in the acropetal sequence, from the base of the flower head towards its top. Therefore, flowers at various development stages are found within the same flower head (from flower buds to blossom fall), which increases the likelihood of cross-pollination. The acropetal sequence of the ex-
plosure of flowers within a raceme is not always observed. A flower near the base is often the last one to open. However, flower explosure from the base towards the top is the dominant trend. After pollinating the flower, the corolla will shirk and fall off. A morphological peculiarity of ovary fertilization is its 180-degree turn on the flower-bearing stem with the plate feed facing upwards. Unfertilized ovaries turn red within 2 or 3 weeks of blooming, then wrinkle and fall off.
Depending on the variety, 30 to 55 days after the end of blossoming, the fruit ripening stage starts. A morphological peculiarity of the commencement of fruit ripening in blueberry is its 180-degree turn on the flower-bearing stem with the plate feed facing downwards. 'Bluetta' is the first cultivar to begin ripening in Belarus (3.07). It is followed by 'Duke', 'Reka' (5.07), 'Northblue', 'Weymouth' (6.07), 'Croatan', 'North-country', 'Patriot' (7.07) and 'Earliblue' (8.07), in which berries turn blue almost at the same time. The above cultivars can be categorized as early ripening. The next group of cultivars that can be categorized as mid-early ripening breeds includes 'Denise Blue' (12.07), 'Hardyblue', and 'Northland' (13.07). Fruit ripening of the classic mid-ripening cultivar 'Bluecrop' begins in mid-July (15.07). Five days later, fruit begins to ripen in 'Darrow', 'Nelson' (18.07), 'Blueray', 'Jersey' (21 .07), 'Coville' (22.07), 'Bluerose' (23.07), 'Carolinablue' (24.07), 'Elizabeth' (25.07), 'Rubel' (29 .07) and 'Herbert' (1.08). The blueberry cultivars, in which fruit begins to ripen 5 to 7 days after 'Bluecrop' are traditionally considered late-ripening (fig).
The fruit does not ripen on a plant simultaneously, and depending on the cultivar, the duration of the fruit ripening stage can vary from 25 ('Northland') to 55 ('Coville') days. The following pattern has been observed: fruit ripening stages are shorter in earlier ripening varieties. The fast-ripening properties of early-ripening varieties were inherited from lowbush blueberry (V. angustifolium) [15].
Overall, the period of fruit development in blueberries from setting to ripening depends on weather conditions and varies from 28-64 days in early-ripening 'Earliblue' to 46-99 days in late-ripening 'Coville'. According to P. Eck [16], the average fruit formation and ripening stage for Northern highbush blueberry lasts from 42 to 90 days. In Southern highbush blueberry, the ripening stage averages 55 to 60 days [17], in Lowbush blueberry, 70 to 90 days [18], and in Rabbit-eye blueberry, 60 to 135 days [19].
Table 4
The average length of the main phases of phenological development of cultivars of blueberries in the cen-
Fruit ripening completes in early and mid-ripening cultivars in August, and in late-ripening breeds in September. 'Coville' and 'Elizabeth' are the two cultivars with the latest fruit ripening stage, which normally ends during the last week of September. In some years, fruits fail to ripen in these two cultivars because of early frosts or cold spells. As a rule, unripe fruits account for less than 20% of the total, and these are mostly smaller fruits. The analysis of weather conditions in September over the past 25 years shows that once in five years early frosts begin in mid-September, and once in three years they happen during the final ten days of the month. The 'Coville' and 'Elizabeth' cultivars notably have their fruit ripen 5 to 7 days earlier and normally have enough time to fully ripen before frosts if sited in a warm spot.
Cultivar Before flowering Bloom End of flowering - the beginning of ripening Ripening
x±mx V, % x±mx V, % x±mx V, % x±mx V, %
Bluecrop 49±11 32 21±4 31 39±3 11 32±5 26
Blueray 53±11 31 20±4 32 45±9 30 30±5 24
Bluerose 49±10 31 17±4 27 48±7 21 40±5 19
Bluetta 44±9 30 21±4 26 31±2 9 35±5 23
Carolinablue 48±10 31 17±4 27 47±5 17 37±7 29
Coville 46±9 30 19±3 21 46±6 18 55±6 17
Croatan 42±9 33 20±3 24 36±3 13 34±4 16
Darrow 47±10 31 20±4 25 44±5 15 47±5 16
Denise Blue 49±11 34 20±4 26 38±3 13 42±5 20
Duke 45±10 32 25±4 25 30±3 14 33±7 30
Earliblue 49±11 35 21±4 34 35±3 14 27±3 16
Elizabeth 48±9 29 20±4 33 48±6 18 48±5 14
Hardyblue 47±10 32 21±3 23 41±3 11 33±4 19
Herbert 53±12 33 17±4 31 55±6 15 36±6 24
Jersey 50±9 27 20±3 19 44±5 15 41±8 28
Nelson 48±11 34 20±4 28 40±6 20 45±6 18
Northblue 46±9 29 22±4 31 36±2 10 33±9 41
Northcountry 45±9 31 22±4 28 38±3 11 34±9 38
Northland 47±10 33 16±4 35 42±5 14 25±4 26
Patriot 43±10 35 19±4 26 38±3 12 37±7 28
Reka 47±10 33 20±3 22 32±2 11 31±3 14
Rubel 52±11 32 18±4 31 51±7 20 41±6 23
Weymouth 46±11 35 19±4 35 38±4 20 37±8 31
r -0.35 -0.30 0.42
LSDo.o5 13.3 4.8 6.0 7.7
= .y
1.7 8.7 15.7 22.7 29.7 5.8 12.8 19.8 26.8 2.9 9.9 16.9
Bluetta Duke Reka Northblue Weymouth Croatan Northcountry Patriot Earliblue Bluecrop Demse Blue Hardyblue Northland Nelson D arrow lueray Jersey
Bluerose Carolinablue Elizabeth
Herbert
Figure - Ripening harvest of different cultivars of highbush blueberry in conditions of Belarus
Vegetative growth and development. Vegetative buds in blueberries emerge a few days after generative buds. In seasons when flower buds froze, vegetative buds were the first to grow.
Highbush blueberry is characterized by the alternation, throughout the vegetation stage, of several periods of intensive growth of shoots with rest periods. Growth of various types of shoots does not begin and end synchronously. The first growth wave begins in late April or early May and ends in mid-June. During this stage, large numbers of branching (fruiting) shoots are formed. In June, growth halts and a rest period begins. Vegetative buds emerge within leaf bases. Following a short-term rest period (about two weeks), some of the shoots of this type give a new apical growth, which ends in the second half of the summer. In late summer and autumn, some of the shoot buds on branching shoots grow in size several times thus differentiating into flower buds.
Unlike branching shoots, formation and replacement shoots emerge and/or continue their growth later and not synchronously, throughout the summer and autumn. Growth in shoots of these types stops because of the impact of low temperatures in autumn. Sometimes blueberry, especially late-ripening varieties, fails to lig-nify its new formation and replacement shoots or those that additionally grow in the autumn and freeze as a result of the first hard frosts [20]. In the second half of September, after night temperatures fall below 5° C,
leaf coloring begins. Leaf fall is observed in late September-first half of October, as a rule, after the first frosts.
The duration of leaf fall depends on weather conditions in the autumn. In warm and rainy weather leaf fall starts later and lasts longer. Leaves remain the longest at the top of the formation and replacement shoots. Leaves fall simultaneously when temperatures decrease gradually and significantly. After a sudden cold spell during a warm and rainy autumn frozen leaves remain on plants until mid-winter, as it happened in 2014.
Impact of abiotic and biotic factors on the phe-nological development of blueberry cultivars. The
analysis of a decade's worth of data about the periods of the commencement of seasonal development stages in blueberry shows a substantial variability of pheno-logical phenomena. In 2008, blossoming started on the 72nd day following the beginning of the vegetation stage, with the average air temperature of 6.8°C. In 2012, the air temperature averaged 14.6°C, and the blossoming stage began 2.6 times faster, on the 28th day of vegetation. Blueberry blossoming lasted 24 days in 2012, with the average air temperature of 14.3°C, whereas in 2007, when the average temperature reached 20.7°C, this phenological stage took only 11 days, 2.2 times faster. The cited data suggest that the commencement and duration of the phenological stages were contingent on the temperature conditions of the respective season. The phenological development of blueberry took longer in cold weather and was a lot
faster in warm and sunny weather, when phenological stages began and ended earlier. In order to estimate the degree of dependence of the duration of the main seasonal development stages in blueberry on ambient temperatures we calculated pair correlation rates (r) (Table 5).
The findings show that the ambient temperature and duration of phenological development stages are in the inverse proportion — the higher the temperature, the shorter the phenological stage. During the vegetation stage, this proportion is manifested in varying degrees. High correlation dependence is observed for the spring development stages — "beginning of vegetation-beginning of blossoming" (r=-0.90 —0.93) and "blossoming" (r=-0.80 —0.88). The high correlation dependence of the duration of the spring development stages in blueberry on the temperature factor can be attributed to the fact that during that vegetation stage, ambient temperatures were changing with high amplitude (6.5-13.5°C and 12.9- 22.7°C) and significant fluctuations produced a profound impact on the phenological development of blueberry.
Table 5
The dependence of the average length of the main phases of phenological development of blueberries from
Correlation dependence proved to be lower for the summer development stages. The correlation between the duration of the fruit growth stage and air temperatures is virtually non-existent (r=-0.17-0.28), apparently, for the same reason — air temperature remained relatively high, and fluctuations were less significant (16.2-20.0°C). This is indirectly evidenced by the insignificant variability of the duration of fruit growth stages by years: 32-38 days for early-ripening varieties, 36-41 days for mid-ripening breeds, and 41-54 days for late-ripening cultivars.
A moderate correlation relationship is observed between the duration of the fruit ripening stage in blueberry and the ambient temperature (r=-0.50 - -0.15), mostly due to the fact that other factors affect the duration of the ripening phase as well. The track record of growing blueberries and many years of observation of fruit bearing show that the rate of fruit ripening depends on the yield, which is evidenced by the strong positive correlation between the yield and duration of the fruit bearing stage in most blueberry cultivars (Table 6).
Development phase Year Early ripening Middle ripening Late ripening
duration, day t of air, °C duration, day t of air, °C duration, day t of air, °C
Beginning the growing season - beginning of flowering 2006 36±3 11.0 40±2 10.0 42±2 10.6
2007 55±2 7.0 56±2 8.3 56±2 8.3
2008 59±7 6.5 66±4 6.8 62±6 8.3
2009 52±4 10.0 54±3 10.1 53±3 10.1
2010 44±2 9.8 45±1 9.8 46±2 11.0
2011 36±4 10.3 41±4 10.3 43±4 10.3
2012 27±3 12.9 26±1 12.9 29±3 12.9
2013 27±1 13.5 28±1 13.5 31±1 13.5
2014 46±4 8.2 49±5 8.3 54±3 8.7
2015 70±2 7.2 73±2 7.2 78±1 7.8
average 45±9 9.6±1.6 48±10 9.7±1.5 49±10 10.2±1.3
r -0.90* -0.93* -0.92*
Bloom 2006 24±3 12.9 24±1 12.9 20±3 16.6
2007 12±1 20.7 13±2 22.7 10±1 22.7
2008 21±1 13.3 22±4 15.7 25±2 15.3
2009 24±3 13.0 20±3 14.8 23±2 14.8
2010 16±2 15.0 18±2 16.5 19±2 16.5
2011 18±3 20.2 17±2 20.6 18±3 20.6
2012 24±2 14.4 23±4 14.6 24±3 14.6
2013 17±2 18.7 17±2 17.1 16±2 17.0
2014 20±4 13.0 20±5 17.0 18±2 16.8
2015 26±2 13.6 26±2 14.9 24±1 14.9
average 20±3 15.5±2.1 20±3 16.7±2.0 20±3 17.0±1.8
r -0.80* -0.85* -0.88*
End of flowering - the beginning of ripening 2006 36±4 20.0 40±5 19.9 54±11 19.4
2007 36±4 18.5 39±5 18.5 50±3 18.5
2008 37±2 17.1 43±2 17.4 43±3 16.7
2009 34±5 17.0 41±3 18.0 42±3 18.2
2010 37±3 18.4 40±3 18.8 45±6 19.9
2011 34±2 18.5 40±2 18.5 41±7 18.6
2012 34±4 16.2 38±2 17.4 44±7 18.4
2013 33±4 18.5 40±3 18.5 48±7 18.4
2014 38±3 17.1 41±3 16.7 48±5 17.9
2015 32±2 18.0 36±1 18.1 51±2 18.2
average 35±1 17.9±0.7 40±1 18.2±0.6 47±3 18.4±0.6
r -0.03 -0.17 0.28
Ripening 2006 27±6 18.9 29±6 18.7 36±8 17.0
2007 29±4 19.4 30±2 19.4 39±8 17.9
2008 34±5 18.8 35±5 18.5 42±5 18.8
2009 35±4 18.5 36±2 17.6 44±7 16.2
2010 25±3 22.1 32±1 22.9 42±4 16.5
2011 36±8 20.7 24±4 18.5 39±6 17.8
2012 40±6 19.7 36±7 18.4 47±9 17.7
2013 41±5 18.3 39±9 18.0 47±8 18.3
2014 25±4 20.5 30±7 20.6 38±8 22.0
2015 41±6 19.4 41±3 19.2 45±6 18.8
average 33±4 19.6±0.8 33±3 19.2±1.0 42±3 18.1±1.1
r -0.50 -0.22 -0.15
*- a statistically significant correlation
Table 6
The dependence of the duration of the phase of fruit ripening (upper number, day) from yield cultivars of ___blueberries (lower number, kg/plant)____
Cultivar 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 r
Bluecrop 30 32 37 37 32 20 36 39 22 39 0.72*
2.1 2.8 1.5 2.3 2.4 0.7 3.9 4.5 1.5 3.1
Blueray 22 36 31 39 26 17 35 25 32 31 0.78*
1.6 2.0 1.8 3.7 1.5 1.2 2.3 1.7 1.7 2.0
Bluerose 24 36 37 50 35 38 39 43 43 49 0.47
0.1 0.6 0.6 0.8 0.6 0.2 1.1 0.2 0.3 0.9
Bluetta 38 31 29 29 30 39 41 49 21 39 0.86*
1.9 2.1 1.8 2.8 2.1 2.9 3.8 4.6 0.6 4.3
Carolinablue 20 25 30 28 44 38 39 47 51 49 0.43
0.1 0.6 0.2 0.3 0.5 0.2 0.3 0.2 0.5 0.7
Coville 41 53 48 48 51 52 75 62 57 60 0.03
1.9 2.7 2.1 2.4 2.5 0.9 2.2 2.4 1.1 1.7
Croatan 33 37 36 36 26 27 36 44 29 35 0.81*
1.0 1.6 2.6 1.9 1.0 0.1 1.4 4.0 0.4 3.5
Darrow 31 42 50 53 46 54 52 49 39 52 0.65*
1.0 1.2 2.0 2.1 1.1 1.3 1.6 2.2 0.8 1.5
Denise Blue 40 30 39 46 34 33 53 56 45 46 0.59
3.5 4.0 3.1 3.9 2.8 3.5 7.9 4.4 3.1 5.2
Duke 21 26 30 32 23 28 53 47 33 35 0.90*
1.4 0.9 1.3 2.1 2.1 1.1 5.7 6.0 1.8 3.7
Earliblue 22 34 26 31 23 21 26 31 25 30 0.77*
1.4 2.7 1.1 3.6 1.5 1.1 2.7 2.3 1.1 3.2
Elizabeth 56 58 45 45 40 44 39 55 45 48 0.75*
3.5 5.0 3.8 3.5 2.0 1.6 0.8 3.6 0.7 3.0
Hardyblue 29 32 33 33 31 21 35 41 30 43 0.70*
1.9 2.7 2.7 3.0 1.1 0.3 1.9 2.8 1.5 2.4
Herbert 24 32 45 53 36 30 35 35 27 40 0.70*
2.3 1.3 3.2 3.7 0.9 1.4 2.3 2.1 1.1 1.7
Jersey 42 27 38 34 40 30 61 57 45 34 0.39
4.5 2.8 3.8 3.6 4.9 2.4 4.4 3.9 1.3 1.5
Nelson 45 42 50 50 40 40 50 58 28 50 0.69*
0.3 0.9 1.1 1.2 0.9 0.5 0.7 3.5 0.2 3.2
Northblue 29 21 26 41 19 57 37 46 17 45 0.89*
3.4 0.5 0.8 6.9 0.6 7.8 2.6 4.5 0.4 8.9
Northcountry 22 20 35 41 21 51 36 49 17 43 0.91*
2.3 1.7 1.1 5.1 1.4 7.9 4.8 7.6 0.5 5.5
Northland 17 26 25 36 31 20 21 21 22 35 0.57
2.7 3.0 3.0 4.5 2.6 2.2 1.5 2.2 1.5 2.3
Patriot 33 20 30 37 33 40 48 45 28 55 0.87*
LIB
3.7 0.6 4.5 4.9 3.8 3.0 6.4 4.8 1.3 6.7
Reka 30 29 29 27 25 40 31 34 32 36 0.57
2.3 2.1 2.2 1.7 1.5 2.9 1.3 1.7 1.6 2.1
Rubel 32 55 40 53 48 37 50 31 28 35 0.87*
4.7 8.0 4.3 8.1 4.3 4.4 7.8 2.3 3.1 4.3
Weymouth 40 30 46 45 28 23 49 28 26 56 0.83*
3.3 2.6 8.0 6.8 4.5 3.6 5.4 3.0 2.0 13.0
According to findings, the higher the yield, the longer the fruit ripening period. Therefore, correlation is higher in early- and mid-ripening varieties, compared to late-ripening cultivars ('Bluerose', 'Carolinablue', 'Coville', 'Jersey'), probably because the fruit ripening stage in late-ripening cultivars ends in early autumn, at lower air temperatures in comparison with the summer period.
The correlation analysis between the main pheno-logical development stages of blueberry presented in Table 4 points to the weak correlation 1) between the duration of the period from the beginning of vegetation to the commencement of blossoming and blossoming itself (r=-0.35), 2) between the duration of the blossoming stage and the fruit growth stage (r=-0.30), 3) between the duration of the fruit growth stage and the ripening stage (r=0.42). The first and second correlations indicate that the blossoming stage in early-ripening blueberry cultivars is longer than in late-ripening culti-vars, because the blossoming of early-ripening blueberry cultivars takes place earlier than in late-ripening cultivars, at lower ambient temperatures. Blossoming of late-ripening cultivars normally takes place later, when temperatures get higher, and this phenological stage takes less time. The third, positive correlation implies that the blueberry cultivars with shorter growth and fruit formation periods, i.e. early-ripening varieties, have shorter fruit-ripening periods. There are two reasons for this: the first one is higher temperatures during the fruit ripening stage of early-ripening varieties; and the second one is the fact that fruit ripening in early-ripening cultivars is more intensive than in late-ripening breeds. This is indirectly evidenced by the fact that fruit in early-ripening cultivars begins ripening 30 to 38 days after blossoming, whereas for late-ripening varieties, the period is 40 to 55 days.
The analysis of literature shows that some researchers also point to the dependence of the duration of the phenological development stages in highbush blueberry on temperature seasonal conditions; however, they do not provide supporting evidence [5, 6, 8]. Only K. Scibisz [21] notes that hot weather during the blossoming stage reduces its duration. According to the author, the increase in the ambient temperature by 1° C facilitates a reduction in the fruit growth period and brings the ripening stage five days closer. According to our findings, in years with higher air temperatures fruit began ripening earlier; however, there was no apparent correlation. In 2006 and 2009, the difference at the beginning of the ripening stage was six days (45 and 39 days, respectively), at the same average daily temperature of 19.3°C. In 2008, blueberry fruit began ripening 39 days after blossoming at the average temperature of 17.4°C, same as in 2009, when the average temperature was higher, at 19.3°C. It looks like the duration of the
fruit ripening stage depends not only on the yield load, but also on other factors that have not been accounted for (leafage level, etc.)
Conclusions
The calendar period for the commencement of vegetation and duration of the seasonal development stages in blueberry cultivars significantly vary from year to year depending on the ambient temperature. The temperature dependence of the phenological development of blueberry cultivars throughout the vegetation period is manifested in different ways. An increase in temperatures in the spring results in a proven acceleration of the seasonal development of blueberry and, consequently, shorter phenological stages. Changes in the ambient temperatures in the summer have a markedly weaker impact on the rate of phenological development in blueberry.
In most of the blueberry cultivars, a strong positive correlation has been observed between the yield and duration of the fruit ripening stage, i.e. the higher the yield, the longer the fruit ripening stage. In early- and mid-ripening blueberry varieties this correlation is higher than in late-ripening cultivars.
The climatic conditions of the central agro-climatic region of Belarus ensure the complete seasonal development cycle in highbush blueberry cultivars of the entire crop range. Only in some years (one in five) a small proportion of the crop (<20%) fails to ripen in late-ripening 'Coville' and 'Elizabeth' cultivars.
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