Creation Of New Small-Size Plant Germplasms Using Tropical And Temperate Types Of Lotus

As the only aquatic plant of the top ten famous Chinese traditional flowers, lotus (Nelumbo nucifera) has a long cultivation history and owns high ornamental, economic values. This article selected two tropical lotuses(Nelumbo nucifera ’Taiguo Honglian’ and Nelumbo nucifera ’Fenyan’) and twenty middle-small size and temperate lotuses as the parents to make cross combinations. It was expected to acquire new cultivars with long flowering, long green period and small size by combining the advantages of tropical lotuses of long flowering, long green period, green early and the temperate lotuses of small size. The main results were as follows:(1) Seed set was diverse among different cross combinations with a rate from 1.96% to 82.61%. The difference also existed when the same cultivar was selected as male or female parent. When the two tropical lotuses were parents, the seed set rate and flowering rate was higher than the crosses among temperate lotuses. And it could reach to 64.24% when the cultivar of Nelumbo nucifera ’Donghuahong’ was selected as the female parent, so this tropical cultivar was a better breeding material.(2) We selected 10 individual plants as large-size lotus,24 as middle-size lotus and 41 as small-size lotus from all the progenies by the comparative analysis between individual plants and parents of the crosses. Simultaneously, we drew these conclusions by analysing the character inheritance between progenies and parents of cross combination 6 and 9:the progenies of the two crosses showed pink flower and 81.18% progenies of all crosses were pink, which indicated that the heretability of pink was higher than other colors. The occurrence rate of stamen-petalloid of cross 6 and 9 was 85.71% and 66.67% respectively, which showed that it was inclined to female parent.(3) We evaluated lotus breeding procedures by the combination of grey system theory and breeding science. The relationship between plant size (the height of standing-leaf or flower stalk) and other characters was discussed by the analysis of grey related degree. And also we selected 20 crosses through grey comprehensive evaluation according to the reference cross of small-size standard made by Chinese Lotus Flower Cultivars (2004). Then we sorted the parents by using grey correlation Q-clustering, chose 65 plants from 20 crosses by the fixed weight coefficient of grey selection, of which 28 plants were better ones which can be used for popularization and application.