Components of phenotypic variability for head diameter in sunflower - Helianthus annuus L.

Abstract

Sunflower is the main crop species for the production of edible oil in many countries of the world, including ours. Plant height and head size, form and position on the stem as well as the number of leaves, their size, duration and distribution on the plant all play an important role in defining optimal plant architecture in sunflower hybrids (Škorić, 1975, 1989, 2002). In order to monitor the mode of inheritance and gene effects for head diameter in the F1 and F2 generations, half diallel crosses were made in six genetically divergent sunflower inbreds. The mean values of the trait in question differed significantly. The mode of inheritance of head diameter in the F1 generation was superdominance in all but four crosses, which had dominance instead. In the F2 generation, on the other hand, the prevailing mode was dominance, while superdominance was recorded in four cases. The dominant component accounted for the bulk of genetic variance, and the mode of inheritance of head diameter taking into account both the F1 and F2 generations was superdominance. These findings may prove valuable for developing high-yielding sunflower genotypes.

Suncokret je u mnogim zemljama u svetu i kod nas osnovna biljka za proizvodnju jestivog ulja. Visina biljke, veličina, forma i položaj glave na stablu, broj listova, njihova veličina, trajanje i raspored na biljci imaju važnu ulogu u definisanju optimalne arhitekture hibrida suncokreta (Škorić 1975; 1989; 2002). U cilju praćenja načina nasleđivanja i efekta gena prečnika glave suncokreta u F1 i F2 generaciji izvršena su dialelna ukrštanja isključujući recipročna sa šest genetski divergentnim inbred linijama suncokreta. Dobijene su značajne razlike u srednjim vrednostima za ispitivano svojstvo. Prečnik glave se u F1 generaciji nasleđivao superdominantno jedino se u četiri ukrštanja javila dominacija, dok se u F2 generaciji nasleđivao dominantno, a superdominacija se zadržala u četiri kombinacije. Glavni deo genetske varijanse čini dominantna komponenta, a način nasleđivanja prečnika glave je superdominacija uzevši u obzir sve kombinacije ukrštanja u obe generacije (F1 i F2). Ova istraživanja mogu biti od značaja u stvaranju visoko prinosnih genotipova suncokreta.