STUDY ON THE HALF-SIB FAMILY SELECTION FOR THE SUPERIOR TREE OF SCOTS PINE

Investigation and rescarches are carricd out in MaocrshanForcst Farm attached to Northeast Forcstry University in 1988. Comparedwith the contrast, 29 superior familics and 21 inferior families areselected from 112 families of half sib and open pollination of seven-year old scots pine stands by using multicharacters correlations analysis and variance analysis (ANOVA) as well as principal component index (PCI) selection. This index selection which collects multicharacters information has more advantage than monocharacter selection. It is very important to select fine famiIies for buildingthe first generation seed orchard and changing from trial stand toseeding orchard.

Study on the variation in and selection of Fraxinus mandshurica provenances and families in northeast China

Fraxinus mandshurica Rupr.is one of the main afforestation species in northeast China,and there is great demand for improved F.mandshurica varieties.The results of an investigation into and analysis of the growth traits of F.mandshurica provenances and families showed that there were significant differences in different periods.However,variations in growth traits decreased year by year.There was a significant negative correlation between tree heights of the provenances and sunshine hours in their areas of origin.The provenances of Xinglong,Hailin and Wuchang were selected based on the volume of 18-year-old trees.The average genetic gain from the selection of fast-growing provenances was 19.4%.Ten superior fast-growing families were selected.The average volume of the selected families was22.6%,higher than that of all families.The correlation coefficient between heights at 6-year-old and at 18a was 0.838for provenances,and between heights at 4-year-old and at 18-year-old was 0.303 for families.These results indicate that early selection for height in provenances or families could be performed at 6 years or 4 years,respectively.Early selection for DBH and volume in families could start at 8 years.

Selection of superior families of Pinus massoniana in southern China for large-diameter construction timber

This study addresses the increasing demand for large-diameter production timber,and considers the time and space variability of half-sib families of Pinus massoniana.Height,diameter at breast height(DBH)and timber volume of 440 open-pollinated half-sib progeny families were investigated in 14 progeny trials in different years and production regions.An evaluation of the genetic variation of all half-sib families was carried out during the sustainable rapid growth period and individual volumes were characterized as a major index.ANOVA analysis showed that there was considerable variance in the growth traits of most families in different years and on different sites.The variations caused by temporal and spatial changes of the mating system required three selection methods for analysis.The results show that there were differences among the heritabilities of different growth traits by different halfsib progenies.Average heritability values of height,DBH and volume were 0.33,0.34 and 0.36,respectively.Fortyfive superior families were selected in every progeny test,12 were selected in progeny trials by different years and five in different habitat progeny trials.Three superior families(Gui GC553A,Gui GC414A and Gui GC431A)were selected,although in different years and production regions.The genetic gains of timber volume of these selected r families ranged from 1.20 to 47.00%,which could provide a foundation for superior wood property selection and serve as material for seed improvement and extension in surrounding areas.

Comparisons of Three Recurrent Selection Methods in the Improvement of Maize Populations

The maize population Csyn 4 was improved for three cycles with three recurrent selection methods MS1, MS1-HS, and MHSRRS in northern China. A total of 40 NC Ⅱ testcrosses were made by four testers with Csyn 4 and 10 improved populations, which were evaluated in four environments in the cropping season of 2005. Analysis of variance indicated a significant progress （P〈 0.05） in yield and other chief agronomic traits in the improved populations and testcrosses, demonstrating that the three recurrent selection methods were effective for increasing grain yield of testcrosses and improvement of general combining ability in maize population. The average grain yield increase of population Csyn 4 in MS1, MS1-HS, and MHSRRS recurrent selections was 266.7 kg ha^-1 （5.3%）, 288.0 kg ha^-1 （5.7%）, and 231.3 kg ha^-1 （4.6%） per cycle, while the grain yield of S 1 progeny of population for Csyn 4 was increased by 420.0 kg ha^-1 （10.9%）, 376.0 kg ha^-1 （9.8%）, and 414.7 kg ha^-1 （10.8%） per cycle in MS1, MS1-HS, and MHSRRS recurrent selections, respectively. Linear responses （b） in the MS1, MS1-HS, and MHSRRS recurrent selections were the same as the realized responses of the selection （G） for grain yield increase of Csyn 4 and S1 progeny of the populations. The grain yield of testcrosses increased by 3.3-5.2% on average per cycle. The value of heterosis did not display any differences amongst the different cycles of selections. The GCA for yield component traits of population Csyn 4 was improved significantly by means of three selection methods, whereas the GCA for plant height, ear height, days to silking, and days to pollen did not show significant increase in the recurrent selections. GCA for the number of tassel branches were decreased in the selections, while GCA for the number of plant leaves were increased, but the difference was not significant.

Phenotypic and genetic parameter estimation of juvenile growth and bottom color traits in half-smooth tongue sole,Cynoglossus semilaevis

Half-smooth tongue sole（Cynoglossus semilaevis） is a commercially important fish species. There were no reports about accurate genetic parameters of growth traits in C. semilaevis, despite efforts aimed at the culture of this species. Therefore, the main goal of this study was to estimate the parameters for the early growth traits（total length, body depth and body weight） of C. semilaevis based on the data obtained from 80 families. The trait of fish with pure white bottom or not（named as the trait of bottom color） was also analyzed. All the heritabilities estimated for the traits were medium, which varied from 0.210 to 0.362. Genetic correlations among growth traits were highly positive, varying from 0.913 to 0.959, indicating that selection of one of the three traits would result in correlated increase in the others. Also, genetic correlations between bottom color and growth traits were positive and varying from 0.241 to 0.353, suggesting that selection for the bottom color can be utilized to enhance the selection of growth traits. In addition, fish from the top performing 16 full-sib families were selected as broodstock, based on the above analysis and the comparison of family breeding value. This research provides an important basic material to implement selective breeding in C. semilaevis.

Variations in growth traits and wood physicochemical properties among Pinus koraiensis families in Northeast China

This study aimed to explore and improve the different economic values of Pinus koraiensis(Siebold and Zucc.)by examining the variations in 6 growth traits and 9 physicochemical wood properties among 53 P.koraiensis half-sib families.Growth traits assessed included height,diameter at breast height,volume,degree of stem straight-ness,stem form,and branch number per node,while wood properties assessed included density,fiber length and width,fiber length to width ratio,and cellulose,hemicel-lulose,holocellulose,lignin,and ash contents.Except for degree of stem straightness and branch number per node,all other traits exhibited highly significant variations(P<0.01)among families.The coefficients of variation ranged from 5.3(stem form)to 66.7%(ash content),whereas,the herit-ability ranged from 0.136(degree of stem straightness)to 0.962(ash content).Significant correlations were observed among growth traits and wood physicochemical properties.Principal component analysis identified four distinct groups representing growth traits,wood chemical and physical properties,and stem form traits.Multi-trait comprehensive evaluation identified three groups of elite families based on breeding objectives,including rapid growth,improved timber production for building and furniture materials,and pulpwood production.These specific families should be used to establish new plantations.

Selected Exhibits of Family Car, PSE' 94

Family Car World Development and China’s Strategy Presentation Seminar and Exhibition ’94 sponsored by Ministry of Machinery Industry, was held during Nov. 14～19 in Beijing. This activity received great support and assistances from related ministries, corporations and meanwhile also aroused interest of