Components of winter resistance in different varieties of sea buckthorn (Hippophae rhamnoides L.)

 

Selekhov V.V., Fefelov V.A., Igoshina V.G., Smertin M.P., Nizhny Novgorod State Agricultural Academy, Russia

 

In Nizhny Novgorod State Agricultural Academy a search for sources of high winter resistance takes place aimed at breeding on tolerance to unfavorable winter conditions. As object of investigation 140 sea buckthorn varieties of different genetic origin were taken. Samples were exposed to common damaging factors of winter period. The factors were modeled in laboratory conditions. Annual shoots were tried in January-March on three components of winter resistance:

  1. Resistance to early frost (shoots were kept for 5 days at +2ºC, for 3 days at –5ºC and for 18 hrs at –25ºC)

  2. Maximal frost resistance (–40ºC) in the middle of winter (hardening: 3 days at –5ºC, 3 days at –10ºC; damaging factor – 18 hrs at –40ºC)

  3. Preserved frost resistance during thaw (hardening: 3 days at –5ºC, 3 days at –10ºC; thaw – 5 days at +2ºC; damaging factors – 18 hrs at –25ºC)

Taking into account lower resistance of flower buds, tolerance was estimated mostly on them.

In the beginning of winter period 63% of present samples had insignificant damages (below 2d degree). Such damages do not influence on commercial yield.

55% of samples withstood the temperature of –40ºC without essential damages (below 2d degree). In 8% of varieties buds died.

After artificial thaw (+2ºC) during 5 days 22% of samples remained hardened and did not damage by the frost of –25ºC. 19% lost hardiness completely.

There are selected 6 varieties damaged less than for 1 degree. Amongst them there are two male forms.