| Dendrocalamus,with modern distribution center in Yunnan,are about 40 species.Moreover,it not only has the most important economic value of forest germplasm resources,with tall culms,the shoots can edible and timbers can be used for construction,but also was one of the most important economic bamboo in tropical and subtropical areas of Asia and Africa.Due to the bamboo flowering phenomenon is rare under the natural conditions,so that the sexual reproduction mechanism has not been detailed research by scientist.At present,the research on bamboo breeding system in China and abroad mainly focused on reproductive biology,especially on the patterns of flower opening,the longevity of various organs,pollen morphology and viability.In recent years,two flowerig types-“sporadic”and “mass”occured some species of Dendrocalamus that distribution in Yunnan,created an opportunities for the study of sexual reproduction mechanism of bamboo.In this project,we intend to study mating system of D.membranaceus(sporadic,group)and D.sinicus(sporadic).Development and use of SSR markers for paternity analysis by using CERVUS 3.0.6 and COLONY2.0 software.Especially,we concerned about selfing and outcrossing rates,male reproductive fitness as well as pollen dispersal patterns in the populations were examined.Consequently,we hope to obtain a more comprehensive understanding about breeding system characteristics of the two bamboo species.According to our results of two different software,we also compared with the results of the classical pollination test,concluded that CERVUS were consistent with it.Therefore,in this abstracts we only illustrated the main findings of CERVUS.In addition,we also investigated the process of natural regeneration of sporadic and group flowering and fruiting populations.The main research results of CERVUS were as follows:1.Sporadic flowering of D.sinicus.A total of 126 and 133 offsprings were collected from 4 clumps in 2013 and 2015,respectively.We had sampled two times,which belonged to different flowering periods in 2013.Among 126 offsprings,87 offsprings,which were outcrossing progenies,could be assigned paternity at the level of 80% in 2013,no selfing offsprings were deteced.In the samples of 2015,among 133 offsprings,128 individuals could be identified the male parent,37 inbred progenies were included,accouting for 28.9% of assigned paternity;and the outcrossing offsprings were accounted for 71.1% of assigned paternity.Therefore,we speculated that the mating system of D.sinicus was mainly outcrossing with self compatibility in the sporadic flowering and fruiting.2.Sporadic flowering of D.membranaceus.We collected 8 culmps individuals as candidate male parent in 2013.Among 101 offsprings,19 offsprings could be assigned paternity at the level of 80%.Selfing progenies had 12 and accounting for 63.2% of assigned paternity;the outcrossing offsprings had 7,which were accounted for 36.8% of assigned paternity.Therefore,we speculated that the mating system of D.membranaceus was a mix mating system and selfing dominance in the sporadic flowering and fruiting.3.Mass flowering of D.membranaceus.We collected 11 culmps individuals as candidate male parent in 2013.Among 350 offsprings,75 offsprings could be assigned paternity at the level of 80%.Selfing progenies had 6 and accounting for 8% of assigned paternity;the outcrossing offsprings have 69,which were accounted for 92% of assigned paternity.We collected 5 culmps individuals as candidate male parent in 2014.Among240 offsprings,36 offsprings could be assigned paternity at the level of 80%.Selfing progenies had 9 and accounting for 25% of assigned paternity;the outcrossing offsprings had 27,which were accounted for 75% of assigned paternity.Therefore,we speculated that the mating system of D.membranaceus was a mix mating system and outcrossing dominance in the sporadic flowering and fruiting4.Analysis of pollen disperal distance and reproductive fitness.In 2013,the line distance of 13 and 6 is 4377.9m,both simultaneously flowering between December and January 2012;the line distance of 5-1 and 5-2 is 201.6m,both with the bloom at March-May 2012.The effective pollen disperal distance was 0-4377.9m and 0-2558.9m in 2013 and 2015 respectively.Which showed a wide spread range to the effective pollen,which may be closely associated in Tufeng insect pollination.The effective pollen disperal distance is 0-72 m of sporadic flowering D.membranaceus,but mainly concentrated in the 0m,which may be related to the lower offspring.The effective pollen disperal distance of mass flowering D.membranaceus was 0-90 m.The relationship between of effecive pollen dispersal distance and male reproductive fitness showed that with the increase of mating distance between femal parent and male parent,the probability of mating success became smaller,and the intensity of pollen flow decreased.5.Natural regeneration of D.membranaceus after sporadic and mass flowering and fruiting.We investigated the natural regeneration in both sporadic and mass flowering populations within 3 years,we found a low natural seed rate ranging from 1.76% to 7.49%,seed set rate of mass flowering were significantly higher than those of sporadic flowering populations.the seedlings died within 2 years of sporadic flowering,leading to a failed natural regeneration.A considerable number of seedlings remained survival after 2 years in mass flowering poputions,height and culm diameter were significantly growth.Observations were made after 2 years to show good natural regeneration. |
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