Cultivation Blackcurrant

1 cultivation

1.1 site selection , planting
1.2 manures , fertilizers
1.3 pruning
1.4 harvesting
1.5 diseases , pests
1.6 research , breeding

cultivation
site selection , planting

blackcurrants can grow on sandy or heavy loams, or forest soils, long nutrient requirements met. prefer damp, fertile not waterlogged ground , intolerant of drought. although bushes winter hardy, frosts during flowering period may adversely affect yield , cold winds may restrict number of flying insects visiting , pollinating flowers. ph of 6 ideal blackcurrants , ground can limed if soil acidic. planting done in autumn or winter allow plants become established before growth starts in spring, container-grown stock can planted @ time of year.

two-year-old bushes planted strong one-year-old stock can used. planting certified stock avoids risk of introducing viruses. on garden scale plants can set @ intervals of 1.5 1.8 metres (5 6 ft) or can set in rows planting intervals of 1.2 metres (4 ft) , row separations of 2.5 metres (8 ft) or more. in uk, young bushes planted deeper initial growing level encourage new stems grow base.

manures , fertilizers

the blackcurrant requires number of essential nutrients present enable thrive; nitrogen provides strong plant growth , stimulates production of flower sprigs; phosphorus aids growth, setting of fruit , crop yield; potassium promotes growth of individual shoots , increases weight of individual fruits; magnesium constituent of chlorophyll , helps increase yields through interaction potassium; calcium required cell division , enlargement , particularly important young plants , buds.

an annual spring mulch of rotted manure ideal , poultry manure can used needs prior composting straw or other waste vegetable material. spent mushroom compost can used care should taken contains lime , blackcurrants prefer acidic soils. blackcurrant gross feeder , benefits additional nitrogen, , phosphatic , potash fertilisers should applied annually. balanced artificial fertilizer can used , 10-10-10 granular product can spread around bushes @ rate of .10 .24 kg (0.2 0.5 lb) per plant. weed growth can suppressed organic mulch such sawdust, bark, mushroom compost or straw, heavy plastic topped organic mulch cover or landscape fabric.

pruning

blackcurrant flowers

fruit in blackcurrants borne on one-year-old shoots. newly planted bushes should pruned severely, cutting shoots 2 buds above ground level. gives plant chance established before needing put energy producing fruit. general rule when pruning remove weak shoots , growing out sideways may weighed down when fruiting. remaining branches should thinned remove old unproductive wood , encourage new shoots. established bush should not allowed become overcrowded , should have 1 third of main branches or stems removed each year. when harvesting machine, plants upright growth habit encouraged.

harvesting

on garden scale, berries should picked when dry , ripe. commercially, harvesting done mechanically straddle harvesters. these move continually down rows, straddling row of bushes, shaking branches , stripping off fruit. blackcurrants placed half tonne bins , minimise stoppage time, machines have cross conveyors direct fruit continuously moving trailers in adjoining row. modern machine can pick fifty tonnes of blackcurrants in day using 1 operator , 2 tractor drivers. bins should stored in cool place. fruit still picked hand use in fresh fruit market.

diseases , pests

blackcurrant

ribes plants susceptible several diseases , number of insect pests. however, new varieties have been developed, or being developed, overcome of these problems.

reversion serious disease transmitted blackcurrant gall mite cecidophyopsis ribis. causes decline in yield , quite widespread in europe encountered on other continents. symptoms include modification of leaf shape in summer , swollen buds ( big bud ) in winter, each housing thousands of microscopic mites. pest control has limited effectiveness, severely infected bushes should destroyed. new plants purchased should certified virus-free.

white pine blister rust (cronartium ribicola) needs 2 alternate hosts complete lifecycle. 1 host plants in genus ribes. on blackcurrant, causes leaves become pale , later develop tiny orange pustules , yellow filamentous coating on leaves. fruit crop little affected leaves fall , growth slowed following year. other host of white pines, in causes serious disease , mortality north american species have not co-evolved rust.

american gooseberry mildew , powdery mildew can infect leaves , shoot tips, , botrytis may cause fruit rot in wet season. currant , gooseberry leaf spot (drepanopeziza ribis) disease of blackcurrants, not serious problem cultivars have resistance.

the blackcurrant leaf midge can cause browning, crimping , distortion of leaves @ tips of shoots seldom serious problem. blackcurrant sawfly (nematus ribesii) lays eggs on underside of leaves , voracious larvae work way along shoots, stripping off leaf after leaf. in serious attack, bush can denuded of leaves. larvae of currant borer drill way along centres of shoots, wilt , die back. other insect pests include scale insects, aphids , earwigs.

research , breeding

there many cultivars of blackcurrant. baldwin mainstay of industry many years has largely been superseded more productive , disease-resistant varieties. during 20th century in europe, hybridisation work has been carried out in order reduce plant s susceptibility disease , frost , increase yields. effort centred on russia, sweden , scotland.

in britain scottish crop research institute tasked developing new varieties suitable growing in north of country. produced new cultivars had greater cold tolerance, in spring, ripened earlier , more evenly , had greater fungal disease resistance. frost tolerance improved selecting late flowering , genetic research identified genes involved in resistance gall mite , blackcurrant reversion virus. ben lomond first of ben varieties , released in 1975. followed several other cultivars juicing industry such ben alder , ben tirran . cultivar ben hope released in 1998 increased tolerance gall mite, , in same year, ben gairn became available. shows resistance reversion virus. gardeners , pick-your-own market, ben sarek , ben connan , big ben introduced , have large, sweet berries. cultivars ben connan , ben lomond , ben sarek have gained royal horticultural society s award of garden merit. , new varieties being developed continually improve frost tolerance, disease resistance, machine harvesting, fruit quality, nutritional content , fruit flavour.

varieties producing green fruit, less flavoured , sweeter typical blackcurrants, cultivated in finland, called greencurrants (viherherukka). in poland, research institute of horticulture has done work on improving blackcurrant regard disease , pest resistance, fruit quality, adaptations local conditions , mechanical harvesting. researchers have crossed various varieties , introduced inter-specific genetic material gooseberry (ribes grossularia), red currant (ribes rubrum) , flowering currant (ribes sanguineum). resulting offspring further back-crossed r. nigrum. cultivars produced include tisel , tiben in 2000 , ores , ruben , tines in 2005. further cultivars polares , tihope being tested. since 1991, new zealand has become important centre research , development, temperate climate particularly suitable cultivation of crop. breeding programmes concentrating on yield, large fruit size, consistency of cropping , upright habit.

in north america, there need fruit have resistance white pine blister rust. new cultivars such crusader , coronet , consort have been developed there crossing r. nigrum r. ussuriense , these show resistance disease. quality , yield of these varieties poor compared non-resistant strains , consort reliably self-fertile. back-crossing these varieties parent have produced new strains such titania have higher yield, better disease resistance, more tolerant of adverse weather conditions , suitable machine harvesting. 2 new releases black currant breeding program in british columbia, canada, blackcomb , tahsis , selected immunity white pine blister rust , frost tolerance.