Study On Cold Tolerance And Combining Ability Of Hybrid Progeny Of Pansies

Pansy（Viola×wittrockiana）is kind of perennial herb of the Viola family Viola,and is often cultivated as a biennial.However,in the area north of the Yellow River in my country,the temperature in winter is relatively low,and it is difficult for common pansy species to overwinter in the open field.Cultivating new varieties of pansy with strong cold resistance and robust plant growth is of great significance to fill the vacancy of winter greening resources,beautify the living environment of cities,and create beautiful villages.In this study,based on the selection of pansy cold-resistant resources,10 pansy inbred lines were used as parents,and 90 hybrid combinations were prepared by Griffing complete dialy hybrid design.Under natural low temperature and artificially controlled low temperature conditions The cold tolerance of the parents and their F₁generation was investigated,and the combining ability and heterosis of the inbred lines of the parents were analyzed.The test results are as follows:1.The results of the freezing injury index under the natural low temperature in the field and the physiological index of the simulated low temperature in the laboratory showed that 10 Pansy inbred lines（EWO-1-1,DPLS-1-2,DSRAB-1-4-2,DSRFY-1-2,E01-1-4,EYO-3-1,JB-1-1-5,JY-2-1,PXP-BT-1-1,XXL-YB-1-1-2）have strong cold resistance and can be used as hybrid parents for cold resistance breeding.2.The comparison results of cold resistance and ornamental value of 90 hybrid F₁generations showed that 9 hybrid combinations（L1×L7,L2×L1,L3×L2,L3×L7,L4×L1,L6×L7,L8×L9,L9×L1,L10×L2）F1generation has strong cold resistance and high ornamental value.3.Among the 9 selected hybrid combinations,the content of cold-resistant physiological indicators after low temperature stress showed the content of soluble protein and soluble sugar of F1 generation,most of which were higher than that of the parent,and only a few combinations showed higher than that of the male parent and lower than that of the parent.The results of female parent or lower than male parent were higher than that of female parent;except for L10×L2 combination,the chlorophyll fluorescence value of 8F₁generation were higher than that of male parent;the content of favorable proline was higher than that of either parent.Comparing the ornamental characters with the parent,it was found that 8 materials were between the parents,and only one material was biased towards the male parent.4.The inbred line L1 has the highest general combining ability in increasing plant height,plant width and leaf length（respectively:1.26,4.98,1.08）;the leaf width of the inbred line L5 has the highest general combining ability（0.29）;In terms of increasing flower diameter,inbred line L2 had the highest general combining ability（0.59）;inbred line L8 and inbred line L4 had the highest general combining ability for the number of flowers,3.01,2.58,respectively;inbred line L6,L8,L10 There was a negative effect on leaf length and leaf width,while the inbred lines L1 and L4 had positive hybrid vigor,the broad-sense heritability of plant height was the highest（69.63%）,and the narrow-sense heritability was the lowest（0.3%）.5.The hybrid combinations with the most significant plant height heterosis are:L1×L10,L8×L9,L1×L8,L4×L7,L8×L9;the combination with the largest plant width heterosis is:L1×L4,L8×L9,L1×L2,L5×L9;the largest combination of leaf length heterosis is:L1×L5,L2×L7,L1×L8;the largest combination of leaf width heterosis is:L4×L9,L8×L9;the largest flower diameter heterosis Combinations are:L4×L10,L1×L10,L2×L4;L5×L8 has the largest hybrid vigor of flower number.