The Study On Polyploid Breeding Of Primula Forbesii

Primula belongs to Primulaceae .Many species of Primula have much higher value of apreciation.Polyploid breeding has became a most important method and it has been also extensively applied in new flora species breeding.A lot of cultivars with big flowers belong to tetraploid (2n=4x=36) in Primula.England have breeded hexaploid (2n=6x=54) cultivars . Primula forbesii,which distributes Yunnan and Sichuan province is one kind of beautiful wild primroses having not been studied completely or cultivated in gardens. P. forbesii has a good exploitation foreground .In this study we used colchicines to induce polyploid Primula forbesii,in order to change the flower diameter ,flower colour and plant pattern and so on .1.In this study ,karyotype and chromosome number studies were carried out on five species within the genus Primula.Ths numbers and karyotypes of chromosome were formulated to be K(2n)=2x=18=16m+ 2sm for P. forbesii. K(2n)=2x=22=20m+2sm for P. secundiflora ,k(2n) =2x=22=20m+2sm for P.sinensis, K(2n)=2x=22=18m+2M +2sm for P. maximowiczii,K(2n)=2x =22=22m for P. serratifolia.lt was the first time of karyotypes report about P. forbesii,P. sinensis P. maximowiczii and P. serratifolia.2.In this study , we used colchicine to induce P. forbesii polyploid ,It was observed the concentration of colchicine at 0.05g L-1 soaking the germinative seeds could get higher variation rate .In this condition one tetraploid was got. The medium added colchicine could get a better induction effect. Concentration of colchicines at 0.1 gL-1 treated for one week could get higher variation rate.In this condition,two tetra-ploids were gotten.3.In the study colchicine induced the sex cell ,we fund that the pollen chromosome doubling effect was related closely with the start treating time to the meiosis phrase . We could get a better induction effect when we treated at the inflorescence out 1/4,or the another co- lor changing from light green to green-yellow color .It was just the period chromosome changed from bouquet stage to diakinesis stage. Synthesizing the ratio of big pollen and the pollen acquiring rate of per inflorescence ,the treating times at 3~5 and every partition 5~7 hours were proper .We could get some ratio big pollen after treated by colchicine.The big pollen ratio could reach to 70% . The chromosome number of the big pollen is 2n=2x= 18 .The big pollen can germinate normaly .After crossing with normal P.forbesii ,we got the fruit which was bigger than the treatment.4.After the treatment of colchicine The outward shape has a big change .The shape of variation plants becomes compact and the plant height becomes short .The petiole becomes short and thick .The shape leaf becomes breadth and obviously thick ,and the color of the leaf become into deep green .The floss on the reverse side of the leaf become more and long.The yellow flower eye and the sepal is bigger than the contrast .The fruit diameter of appearance variation plants is bigger than the fruit diameter of contrast.