关键词: 麻竹, 开花生物学, 繁育系统, 杂交育种

Abstract: [Objective] The breeding system of Dendrocalamus latiflorus was studied to detect its floral and seed-setting characteristics thus to facilitate its crossbreeding. [Method] Pseudospikelet was anatomized, flowering process was observed in the field, pollen viability was determined by in vitro germination test, stigma receptivity was determined by benzidine-hydrogen peroxide, and the type of its breeding system was estimated by outcrossing index (OCI) and pollen-ovule ratio (P/O). [Result] Pseudospikelet of D. latiflorus grows at rachises of different developing levels, and the 2-3 latent buds at the base of each pseudospikelet would develop into new pseudospikelet, thus it blooms continuously during the growth season. 7-10 florets grows on each pseudospikelet, those florets blooms from top to bottom during 5-7 days on each pseudospikelet, the pistil matured 1-4 days earlier than the stamen. Usually, only the 3-4 florets on the top would exerted from the hull while the rest would not, thus resulted in pollination and seed set on the top of each pseudospikelet. Stigma has pollen receptivity from the day it exerted out, and the receptivity becomes stronger on the 3^rd to 4^th day, followed with stigma wither and dry after 6 days. Fresh pollen germinated at an average rate of 27% with a peak of 54.6%; in-vitro preservation of pollen is difficult, 3% germinated after 36 h at room temperature, low temperature and drying treatment could not prolong its life. If anther were preserved at 4℃,the pollen life would last a little longer.[Conclusion] In crossbreeding experiment, if D. latiflorus was used as male parent, pollination should be conducted on the day that the pollen dispersed from the anther; if it was used as female parent, pollination should be conducted from the day that the stigma exerted from the hull. Based on the OCI of Dafni and the P/O of Cruden, the breeding system of D. latiflorus was given priority to outcrossing, and partial self-compatibility; however, bamboos are a group of plants with asexual reproduction, flowering plants at the same period may be clones with the same genetic background, so the pollination among different individuals may be selfing or inbreeding, thus "inbreeding depression" should be avoided during the sexual reproduction of bamboos.

Key words: Dendrocalamus latiflorus, floral biology, breeding system, crossbreeding