SPONTANEOUS SOMATIC MUTATIONS IN THE SIBERIAN CONIFEROUS SPECIES
AND ITS USAGE IN BREEDING PROGRAMMS
Khutornaya E.M., Goroshkevich
S.N., Yamburov M.S.
Institute of monitoring for climatic and
ecological systems SB RAS, Russia
Most of criterions of morphogenesis and growth
varied gradually within tree crown. However, some
times it changed suddenly and these changes are noted as somatic mutations. One
of the most interesting somatic mutations in coniferous species are so-called
"witches,-brooms" (WB) – the crown fragments (local branch
systems) with abnormal morphogenesis. In courses of phytopathology
the classical conception of pathological origin of WB (fungi, mycoplasmoses and virus) prevails. At the same time, there
are evidences of existence of presumably mutational origin WB. They are differed
from pathological WB by normal viability, high longevity and sporadic
distribution. We analyzed the growth and the generative development of several tens
of coniferous WB from Siberia and Far East,
and also its vegetative and seed progeny in comparison with that of the normal
crowns of the same trees. Characteristics of WB (special growth, morphogenesis
and cone production) are remained completely at the grafts. The WB seed progenies
were segregated on two discrete classes: (1) the normal plants, (2) the plants
with slow growth and intensive branching, ratio of the classes numbers is 1:1. In
this case, the normal progenies of WB (the class 1) were not differed from the
progenies of the normal crowns of the same trees. This gives evidence that WB is
the predominant somatic mutation. WBs has a variety
of forms, this give the extensive possibilities for selection and breeding.
Some WB clones of Pinus sibirica have
the valuable characteristics: high viability, slow growth, early cone
production, abundant cone production and normal quality of the cones. The clone
archive and the test plantings were established for the further observations and
tests of WBs. The breeding device was developed for the
Pinus sibirica
grafts and stocks growing slowly, early or produced abundant cone crop. The
results open the way for use of WB in breeding programs for genetic improving of
Pinus sibirica as a
nut-bearing species. The first generation of the sort-clones can be
certificated after 10-15 years of the observations. In
the future we plan to extend P. sibirica genetic polymorphism by controlled crossings
and subsequent selection of the preeminent genotypes as the candidates in the
sort-clones. For these purpose the controlled crossings of WB vegetative progenies
with the normal clones distinguished by various useful characteristics such as abundant
pollen or cone production, early cone production, high quality of cones and seeds
will be used widely. Testing of the seed progenies will allow to extend the
genetic polymorphism of breeding material and to ensure significant improvement
of the sort-clones in the future. The suggested device is the consecutive
alternation of crossing and the selection in the families. This process is
continued during 15-20 years and end in hatch of new grade-clones. The WB seed generation
will use also for hatch of the stock of the grade-populations and the
grade-lines.
This work was
supported by RFBR, grant № 07-04-00593-а