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Browsing by Subject "puolikääpiö"

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  • Heino, Fanni (2015)
    Finding a hybrid breeding method for turnip rape (Brassica rapa L. ssp. oleifera (DC.) Metzg.) would allow the breeding of semi-dwarf cultivars that usually tend to lodge less and have a higher yield index. Some dwarf genes can shorten not only stem but also root which is not optimal for water and nutrient uptake. The effects of the dwarf gene BREIZH (Bzh) on turnip rape have not been reported earlier. The aim of this research is to investigate the effects of the Bzh gene on the structure of shoot and root of turnip rape and estimate if Bzh could be used in breeding semi-dwarf turnip rape cultivars. The research was organized in Viikki Greenhouse in Helsinki, and four turnip rape F2-lines were used in research. The progeny was presumed to distribute according to Bzh gene 1 : 2 : 1 (dwarfs : semi-dwarfs : wild types). Also field experiment was organized but it had to be discarded because of damages caused by geese. In the greenhouse the genotype was estimated twice according to length of hypocotyl. The starting and finishing time of flowering was recorded. After flowering the stems were cut from root and the height of stem and also the heights to the lowest and the highest branches were measured. The number of branches and nodes were counted as well. The roots were washed and the length of the main root and the dry weight of the root were measured. The correctness of the genotype estimate that was formatted by estimated hypocotyl length and measured stem length was evaluated by High Resolution Melting analysis. The control samples were sequenced in order to get information about the base sequence in mutation area. The Bzh gene shortened the stem by shortening the internode length. Also height to the lowest branch was significantly lower in semi-dwarfs. Usually these features together cause the better lodging resistance of the semi-dwarf cultivar. The gene also increased the amount of branches but didn’t affect the amount of nodes. Bzh didn’t affect the length of the main root but slightly decreased the dry weight of the root. There was a large variety in the appearances of the roots. Bzh also delayed flowering and decreased duration of it by one day. HRM analysis is a quick method for determining the Bzh genotype in turnip rape. Estimating genotype by phenotype of the plant is only directional. The Bzh mutation is a mutation of two single nucleotides (G-->A) and it is similar on both turnip rape and oilseed rape. According to the effects on structure, the Bzh gene seems to be suitable for breeding semi-dwarf turnip rape cultivars in future.