Studies On Tetraploid Induction And Cross Of Primula Forbesii

Primula forbesii, one of the wild species of Primula L., has been introduced to Beijing for 2 years. In this paper, five concentrations of colchicine were applied (0.1,0.2,0.5,1.0 and 2.0g/L) for 12, 24,48 and 72 hours to induct tetraploid of P.forbesii. Treatments show a considerable effect on the germination, growth and development of P. forbesii, examination of the result of induction reveals that all treatments produced 94 tetraploids, and treated with 0.1 or 0.2 g/L colchicine for 48 hours yielded the highest numbers of tetraploid plantlets.Morphological and cytological observation shows that the leaves and the flowers of tetraploid plants are respectively thicker and larger than diploid ones. The chromosome number of tetraploid is 2n=4x=36,while that of diploid is 2n=18. Furthermore, paper report the crossability of the tetraploid with tetraploid or diploid, progeny from crosses of tetraploid with diploid are tetraploids, diploids or aneuploids. The traits of F₁ seeds are basically influenced by the female parent, when diploid is the female parent of the cross, seeds are generally empty, lacking both embryo and endosperm.Tissue culture is used in order to reproduce tetraploid. Result shows a great deal of adventitious shoots are obtained on MS medium supplemented with 2mg/L6-BA and 0.1mg/LNAA when axillary buds used as explants, shoots regeneration rate vary between 0 and 68.2% when leaf segments were used as explants.A self-fertile long homostyle (H-2) and a self-infertile short homostyle(H-l) variation are found in progenies of tetraploid plantlets, H-2 combines the pin female characters with the thrum male characters so that the anthers are in the thrum position and the stigma in the pin position, P-1 just opposites to H-2.At the same time ,a new doubles mutant of P. forbesii are also described in this paper firstly, the different character of mutant is that its have 2 whorled petals, pink corolla with up to 5 small lobes inserted in the center, small lobes slightly shorter than normal ones and very variable in shape.