Induction Of 2n Pollen By Colchicine And Germination Characteristics In Rosa Hybrida

Rosa hybrids undergo a long history of breeding and one of its main breeding method is polyploidy hybridization.'Old Blush' is a Chinese ancient diploid rose and it has the feature of continuous flowering and several good characteristics.However,a great deal of the modern rose is tetraploid.Heterogeneous polyploidy can solve the problem of hybrid infertility through 2n pollen and use the genetic resources of 'Old Blush' and 'Slater's Crimson China' effectively.(1)The meiosis of 'Old Blush' pollen is continuous and asynchronous,the effective stage of induction treatment is early meiosis,when pollen mother cells(PMC)are in the leptotene to anaphase I.The results of cytological observations showed that the FDR 2n pollen were developed from parallel(fused)spindle and vertical spindle.The SDR 2n pollen were developed from the defeated cytoplasmic division or nuclear division at meiosis ? stage of PMC.(2)The best treat:24 h with 5%concentration of drugs,were selected that 4.31%active 2n pollen can be induced by colchicine injection which is combined with encapsulation.Colchicine can increase the yield of 2n pollen and the proportion of FDR 2n pollen.Abnormality in 2n pollen,pollen fragments and the change of the aperture from colpate to porate in 2n pollen showed in the pollen samples treated with colchicine.(3)The 'Old Blush' pollen germinated at 4 h after pollination,entered the transmitting tissue of the stigma at 8 h,grew into the style at 24 h and finally entered the ovary at 72 h on both female parents.The proportion of 2n pollen increased significantly while it traversed the stigma and entered into style(8-24 h)where showed strong competitive advantage.The callose plug in the 2n pollen tube was significantly thinner than that of the In pollen tube.(4)The growth activity of the induced 'Old Blush' pollen tube in the pistil is lower than that of the natural pollen with the phenomenon of abnormal morphological.But,there is a certain proportion of the 2n pollen tube entering the ovary.The percentage of 'Slater's Crimson China'induced pollen germination rate and the proportion of stigma and style in 'Carefree Beauty' was significantly higher than that of natural pollen,which reflects the utilization value of pollen induction in hybridization.This study recorded the production of 'Old Blush' 2n pollen in detail,obtained the induced 2n pollen that could germinate on the pistol and observed the occurrence and morphological differences of the competitive advantage of 2n pollen as well as the expression of induced pollen in pollination.