Studies On Genetic Diversity And Hybrid Progeny Genetic Variation Of Bambusa Chungii And Dendrocalamus Latiflorus

Bambusa chungii and Dendrocalamus latiflorus are important timber bamboo and ediblebamboo species in south of China. 8 provenances of B. chungii were collected from it naturallydistributing geographical region and a provenance testing with 8 provenances was establishedby a study team from the Research Institute of Subtropical Forestry, CAF. 30 hybrid familiesobtained via artificial crossing between different provenances of D. latiflorus were planted inNanjin, Fujian provenance and Nanxiong, Guangdong provenance respectively for comparing.Studies on gene-diversity of B. chungii and genetic variations in hybrid offspring of D.latiflorus populations were developed based on material above.1. Morphological gene-diversity analysis for B. chungii: The analysis showed that there wereabundant variances in main morphological traits among the different provenances and all thevariances reached significant or great significant level. Genetic variations emerged because thepopulations growing in segregated regions for long time and low gene flow among and withinthe populations. There also a higher variable ranges within the same population. The geneticdiversity of B. chungii population was abundant. Heritabilities of the main characteristics of B.chungii were strong and stronger. The correlative coefficients among DBH, height, clear height,nodes number under the first branch, and node length at DBH were significant and positive,that would benefit for multi-traits improvement synchronously. The correlation analysisrevealed that thermal factors were limiting factors for growth and distribution of B. chungii,which reflected climate changes from cold to warm in the distributing area of this species.Selection for all the populations was given on the basis of synthesis evaluation. Theprovenances i. e. Zengcheng, Huaiji, Xinyi and Guilin were considered the optimal provenancesfor extension in the region around southwest of Guandong Province.2. Variations analysis of pulpbamboo properties of B. chungii and the optimum sources screen:fibre length, fibrin and 1% NaOH extraction contents had significant difference among 8provenances. The absolute variations of lignin content and fibre length in different provenanceswere low, which suggested that those two traits were unnecessary to be included in theselection program. Superior clump with lower benzo-alcohol extractive content could be selected because large differences among all clumps tested in this study. A decrease tendencyof fibre length and fibre length-width ratio from south to north (high altitude to low altitude)was found.Heritabilities of fibrin and fibre length were strong, while 1% NaOH extraction contents'Heritabilities was medium, and lignin and fibre width got trivial genetic control. The results ofcorrelation analysis between culm properties and growth or yield traits presented there werehighlighted negative correlation between 1% NaOH extraction, benzo-alcohol extractivecontents and yield but significant positive correlation between fibrin content and yield. Tenselyrelationship was detected between fibre form indices and growth or yield traits. Most of theresults discovered were favorable for optimum pulpbamboo selections associating with growthand yield characters. 4 provenances i. e. Huaiji, Xinyi, Nanning and Guilin have been selectedas superior sources based on principle component analysis combined pulpbamboo properties,growth and yield traits.3. Genetic variation analysis of growth traits for hybrid offspring of D. latiflorus: For shootnumber, collar diameter and height, there were significant differences among 30 familiesbecause of rich genetic variance, while the coefficient of variation (CV) of the 3 traits was13.69%-44.33% in two testing sites. Each 6 families have been selected as superior familiesbased on subordinate function value from two sites. The raise of shoot number, collar diameterand height were25.3%, 11.69%, 18.38% at Nanjin and 23.8%, 14.1%, 12.9% at Nanxiong.Combined variation analysis on 3 traits showed that the interaction between genotype andenvironment was highly significant. Heritabilities of 3 traits and the expectant genetic gain atsingle site at Nanjin were higher than at Nanxiong.4. Evaluation of the genetic variation of the hybrid descendants of D. latiflorus based on ISSRmarkers: 9 ISSR primers were utilized to analyze the genetic variance of 22 hybrid familieswith ISSR techniques. The results demonstrated that Nei's gene diversity(He) and Shannon'sinformation index were 0.3655 and 0.5442 at the species level respectively. Genetic similaritycoefficient ranged from 0.3953 to 0.7907 and genetic distance ranged from 0.2348 to 0.928 in22 hybrid family populations. The mean of genetic similarity coefficient and genetic distancewere 0.6130 and 0.4996 respectively, which proved that the hybrid population had a highergenetic diversity and gene resources could be enriched by crossbreeding. 5. Bamboo shoot nutrient content variation of the hybrid descendants of D. latiflorus: Therewere great variance ranges in content of Water-soluble carbohydrates, starch, dissociate aminoacid and protein among different family, the CV of these indexes were 23.69%, 26.70%, 38.26%and 15.76% in turn. Proportion of essential amino acid exceeded 30% in all families andfluctuated between 33.8% and 42.97%. All of the families could be classed into 3 clusters onbasis of similarities of contents of Water-soluble carbohydrates, starch, dissociate amino acid,protein and Proportion of essential amino acid. 11 families included in clusterⅠand clusterⅡwere excellent families at nutrient quality with higher contents of dissociate amino acid,protein and Proportion of essential amino acid. 10 of them had one common parent JD or HKprovenance at least. It indicated that bamboo shoot nutrition of D. latiflorus was controlled bygenetic, excellent hybrids at nutrient quality could be obtained by crossbreeding with suitableparents.6. A first studies on activities of several enzymes of the hybrid descendants of D latiflorus:Activities of sucrose phosphate synthase(SPS), sucrose synthase(SS), glutamine synthetase(GS)and glutamate synthase(GOGAT) were investigated in this research. The results indicated greatdifference of the activities of 4 enzymes in all families. The number of activities of SS, SPS,GS and GOGAT varied from 24.72μmolsucrose.g^-1·h^-1 to 68.87μmolsucrose·g^-1·h^-1,44.91μmolsucrose·g^-1·h^-1 to 267.55μmolsucrose·g^-1·h^-1, 3.48μmol·g^-1·h^-1 to 14.78μmol·g^-1·h^-1,0.0111 to 0.2806 unit in turn. Correlation coefficient between dissociate amino acid andGOGAT activity was significant, which expressed higher activity of GOGAT would promoteassimilation of ammonium and accumulation of amino acid. GOGAT could be considered asone of the physiological index to evaluate the capacity of ammonium assimilation of Dlatiflorus.