Zbornik - Društvo genetičara Srbije

IV-Usm-18 ZBORNIK ABSTRAKATA III KONGRESA GENETIÈARA SRBIJE 107
Subotica, 30. novembar - 4. decembar 2004.
PROMENLJIVOST BROJA I MORFOLOGIJE HROMOZOMA I
OPLEMENJIVANJE GOLOSEMENICA
Mirjana Šijaèiæ-Nikoliæ, A. Tucoviæ i Dragica Vilotiæ
Šumarski fakultet, Beograd
Rezultati obavljenih citogenetskih analiza vrsta golosemenica, prikazuju da èetinare
karakteriše evolucija na diploidnom nivou, što svedoèi o stabilnosti kariotipova i
idiograma ove grupe drveæa i bunja. Kod golosemenica, prirodno visok osnovni broj
hromozoma poznat je samo za tri od 359 vrsta. Golosemenice su grupe drveæa, reðe
bunja sa relativno krupnim hromozomima sliènim kariotipovima i idiogramima.
Osnovna panja usmerena je na unutarvrsnu citogenetsku diferencijaciju politipskih vrsta
(13%) u odnosu na osnovni broj, kao znaèajnu osnovu za bru determinaciju homologih
hromozoma, izradu kariotipova, idiograma i kartiranje gena u kombinaciji sa razlièitim
tipovima ukrštanja odabranih individua. Uoèene specifiène unutarvrsne karakteristike
(razlièiti osnovni broj hromozoma, aneuploidiji, dopunski B-hromozomi, pojedinaèna
pojava poliploidije, prvenstveno na mladim oglednim biljkama) nisu unikalne jer su
opisane kod veoma udaljenih rodova. Uverenje o evolucionoj stabilnosti osnovnih
diploidnih brojeva hromozoma protivreèe, upravo, specifiène citogenetske karakteristike
47 tzv. politipskih (polimorfnih) vrsta golosemenica.
Prema evidentiranim tipovima vrsta golosemenice (monotipske i politipske po osnovnim
brojevima hromozoma) karakteriše drevna (spora) evolucija hromozoma, kariotipova i
idiograma, za razliku od vrsta skrivenosemenica koju karakteriše manje-više brza
citogenetska evolucija. Citogenetska, kariološka i druga istraivanja rodova i vrsta
osetno olakšavaju oplemenjivanje ekonomski znaèajnih vrsta golosemenica.
VARIABILITY OF CHROMOSOME NUMBER AND MORPHOLOGY
AND IMPROVEMENT OF GYMNOSPERMS
The results of the published cytogenetic analyses of gymnosperm species show that conifers
are characterised by the evolution at a diploid level, which proves the stability of
karyotypes and idiograms of this tree and shrub group. In gymnosperms, the naturally
high basic number of chromosomes is known only in three of 359 species. Gymnosperms
are groups of trees, more rarely shrubs, with relatively large chromosomes similar to
karyotypes and idiograms. The attention is focused to intraspecific cytogenetic differentiation
of polytypic species (13%) compared to the basic number. This is a significant base
of a faster determination of homologous chromosomes, development of karyotypes,
idiograms and gene mapping in combination with different types of crossing of the selected
individuals. The specific intraspecies characteristics (different basic number of
chromosomes, aneuploidy, accessory B-chromosomes, individual occurrence of
polyploidy, primarily in younger test plants) are not unique since they are described in
very distant genera. The belief on evolution stability of the basic diploid chromosome
numbers is contradicted by the specific cytogenetic characteristics of 47 so-called
polytypic (polymorphic) species of gymnosperms.
Based on the recorded types, gymnosperm species (monotype and polytypic by the basic
numbers of chromosomes) are characterised by the ancestral (slow) evolution of chromosomes,
kariotypes, idiograms, while angiosperm species are characterised by more or less
fast cytogenetic evolution. The cytogenetic, karyologic and other study of genera and
species support the breeding of economically significant species of gymnosperms.