ABSTRACT
OBJECTIVE: To determine the possibility of heterosis utilization by male sterility in Platycodon grandiflorum. METHODS: The analysis of variance, heterosis over standard and correlation on 12 agronomic in 18 crossing combinations were carried out. RESULTS: Except the dry weight of upground part of plant, the length of main root and the diameter of middle part of the main root, all other agricultural traits were different significantly among the 18 F1 combinations. The diameter of middle part of the main root had the highest coefficient of variation and the ratio of fresh weight of main root and total root had the lowest coefficient of variation,which was 85.42% and 3.66%, respectively. For the traits related to the yield of root,average heterosis over standard in fresh main root and total root was 42.35% and 45.50%, respectively; For the traits related to the form of root, the diameter of up part and middle part of main root had a middle heterosis over standard, which was 12.38% and 29.97%, respectively. The shoot growth was significantly related to its root growth in combination (0.651). The number of nodes on main stem was significantly related to five out of six traits of root in hybrids. CONCLUSION: Variation of agricultural traits in crossing combination is rich, heterosis of traits in root is evident,and F1 hybrids with good yield and the forms could be selected from these combinations. The Platycodon grandiflorum of crossing combinations have reasonable morphological characteristics, and the number of nodes of main stem could be taken as the selected index. All show us that the heterosis by the male-sterility could be utilized in the breeding of Platycodon grandiflorum.
