The Grey Analysis, Kriging and Selection Index of Flower Yield in Rugosa Rose

The analysis of grey system, kriging interpolation, and integration selection index were employed to investigate the relationships between the flower yield/plant (FY) and 15 other quantitative traits of 20 rugosa rose cultivars. The result showed that: The grey relational grade (GRG) of the number of flowers/plant (NF), the number of branches/plant (NB), the width of floral bud (WB), and the weight/flower (WF) to the FY were larger (＞0.5); FY improved with the increase of NF and NB. Moreover, the indirect selection of either trait could not achieve improvement of FY. It is necessary to improve FY by multi-trait selection. The integration selection index (ISI) equation of FY was established with the characters NF, NB, WB, and WF: I=0.3187x1-318.6x2+670.1x4+6.3x8, index heritability=0.8014, selective response of the integration breeding value=245.8811. This will provide a theoretic basis for the genetic breeding of rugosa rose.