ЭлБиб

H E A L T H Y P L A N T S A N D M IC R O P R O P A G A T IO N

EFFECTOF

NVITRO

LONG-TERMSHOOTMULTIPLICATIONFOR

MASSCLONALPROPAGATIONOFBIRCHANDPOPLAR

O.S.Mashkina, T.M.Tabatskaya, L.M.Starodubtseva

Research Institute o fForest Genetics and Breeding, Russia, 394043, Voronezh,

Lomonosov str., 105. E-Mail:

ilgis@lesgen.voronezh.su

Using o f tissue culture methods opens great prospects for mass

reproduction and preservation of a valuable gene pool of broad-leaved woody

species.

We studied a regeneration capacity of

in vitro

long-term cultivated

Karelian birch with patterned wood and five productive triploid forms of P.

alba and P. canescens which are dif-ficult for propagation by traditional

methods. Plant regeneration from stem (in birch) and nodal (in poplar)

explants of adult trees was performed using our original technology (Butova,

Tabatskaya, Skrobova, 1990; Mashkina, 1995). Long-term (during 4-6 years)

repeated (once per 6 months) shoot multiplication was carried out on Boulay

(1980) medium without hormones for birch and on halfstrength MS medium

( Murashige and Skoog, 1962) for poplar

The possibility of

in vitro

all-the year-round micropropagation of birch

(during 6 years) and poplar (during 4 years) without aging symptoms and

loss of regeneration capacity is shown. The optimal duration for one cycle of

shoot multiplication of plantlets was found to be 2-3 months. During this

period each plantlet gives 4-5 nodal segments with one axillary bud in birch

and 6-10 ones in poplar. After one year (4-6 cycles of shoot multiplication) it

is possible to obtain up to 500 thousand or one million microshoots of birch

and poplar, respectively. The sprouts of long-term shoot multiplication were

characterized by good growth and high rhizogenesis

in vitro

, regardless of

the season. Plantlets showed high survival rate and adaptation to changeable

environments: laboratory, greenhouse, field. Seedlings were homogenous

on morphological properties.

Thus,

in vitro

long term shoot multiplication is one of the ways to simplify

and to intensify the clonal propagation of adult birch and poplar trees. The

method described excludes the laborious and prolonged season-dependent

initial stage of annual explantation and renewal of the starting cultures.

Besides, multiplication coefficient increases due to a ll-the year-round

propagation of plantlets and mass yield of seedlings. Rare subcultivation

(once per 6 months) with the preservation of plant regeneration gives a

possibility to keep

in vitro

the valuable genetic material of the forest tree

species and to maintain the juvenile of adult initial genotypes.

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