Articles
EVALUATING INITIAL AND BREEDING MATERIAL FOR WINTER-HARDINESS
Experimental data shows that varieties of different ecologogeographical groups of Prunus armeniaca differ between each other by dormancy duration of flower buds and also by extent and duration of thermal tension necessary for their opening.
Varieties of the European group are characterized with shorter period of dormancy, those of the Central-Asiatic one – with longer dormancy period, while the Iran-Caucasian varieties take the position near to the European group.
Thus, on 23rd, January, all flower buds of var.
Pozdni Khramova break the dormancy in variety Shalakh only 82% and in Kursadyk on this day only 28% flower buds break their dormancy.
Analysis of the seed progeny of the varieties mentioned above has shown that their seedlings, on the whole, retain the specific characters of the dormancy period of the initial forms.
At the same time, variation of this character is observed in every family.
Among seedlings of the European varieties, there occur 23% plants with higher winter-hardiness of flower buds, whereas among the Central-Asiatic ones they are twice as much.
Studies of the seed dormancy period revealed a number of specific characters which allow to make a preliminary selection of forms with higher winter-hardiness of flower buds.
They have been revealed when sowing seeds from free pollination preliminarily divided into batches as they germinated during their stratification.
The analysis of data obtained has shown that in the family of Pozdni Khramova there were 24% winter-hardy seedlings that were obtained from the first batch of germinated seeds, in Shalakh there were 60% winter-hardy seedlings whose percentage of damaged flower buds did not exceed 20% for several years.
From seed germinated later few winter-hardy forms have been obtained.
A similar picture was also noted in the Kursadyk family in which the first seed fractions gave 83.4% winter-hardy forms.
All this give us the chance for preliminary selecting the breeding material.
After having selected first germinated seed batches one can ensure in them high percentage of winter-hardy seedlings.