The Primary Studies On Inheritance Laws Of Main Ornamental Characters And Heterosis Of Zinnia Elegans

Zinnia elegans is an important ornamental plant used in the summer and autumn. However,the study on character inheritance laws and heterosis use of Zinnia is not systematical inland and oversea.In the first study four inbred lines and a couple of two-type lines of Zinnia were selected as parents for crossing according to the NCⅡcross method.Firstly,the heterosis of main ornamental characters and seed set were investigated on 12 Fls;On the other hand,the studies on inheritance laws were carried out for 13 main ornamental characters.Secondly,four inbred lines of Zinnia were selected as parents for crossing according to the Griffing diallel cross method 1.The main results were as following:1.In the crossing according to the NCⅡcross method,Fls have got an high rate of seed set rang from 70.62%-83.75%.High heterosis was observed in most of Fls,and Ms5×S5 got highest rate of seed set(83.75%).Germinating rate of Fls was ranging from 52.3%to 72.4%which showd high heterosis.Over-low parent heterosis was observed in initial bloom stage of ten Fls ranging from 4%to 12%.It was indicated high heterosis on diameter of inflorescence(15.54%) and number of branches(21.05%).According to the g.c.a,there was no significantly different among 6 parents.According to the g.c.a,it was indicated that the largest inflorescence and the most of whorls of ray florets across capitulum was obtained in Mah003×A3,Mah003×S5,Mah003×J10.The results of heritability analysis indicated that the broad heritabilities(h2B) of different traits varied from 36.7%to 76.41%with an average of 55.46%,and the narrow heritabilities(h2N) varied from 0 to 29.88%with an average of 8.88%.Both h2N and h2B were high for length of node,so it could be effectively selected in the early generations.The selection for other traits could be delayed to later generations because of low h2N and h2B. Combinations Ms5001×S5 and MAH003×A3 showed high seed setting and germinating rate,which could be as the new species push into the market2.In the crossing according to the Griffing diallel cross method 1,the rate of seeds set which ranging from 29.28%-66.43%showd high heterosis,and A3×Al got the highest rate(66.43%).Germinating rate of seeds was significantly different among 12 Fls ranging from 23.61%to 89.10%,transgressive heterosis was observed in the germinating rate of ten Fls.Over-low parent heterosis was observed in initial bloom stage of ten Fls ranging from 6.67%to 13.33%.High heterosis was detective on number of branches and pedicel length and diameter of inflorescence and diameter of center disk varied from 29.89%to 7.01%.According to the g.c.a,it was indicated that we shoud choose parents of J6 for breeding large flower size,and parents A3 was the best choice for smaller plant size. The g.c.a indicated that the largest inflorescence and the most of whorls of ray florets across capitulum was obtained in J6×A3,which also had inverse domino offect in crown size and length of node.The results of heritability analysis indicated that both h2N and h2B were high for plant height,so it could be effectively selected in the early generations. The other traits could be delayed to later generations because of low h2N and h2B. Combinations J6×A1,J6×A3 and A3×A1 showed high high seed setting and germinating rate,which could be as the new species into the market.