| Juglans mandshurica Maxim.is the important wood,medicinal,oil species with high economic value in northeast China.In order to find out the variation pattern of seed morphology and kernel composition of Juglans mandshurica Maxim.,establish selection technology and comprehensive quality evaluation system,and select excellent materials.247 individuals’ fruits from 12 J.mandshurica populations were collected in its main natural distribution area for the research,the results would provide theoretical basis and breeding materials for genetic improvement of J.mandshurica.The main results are as follows:(1)There were significant differences in seed morphology and kernel composition among and within populations.There were rich variation in seed morphological traits,and the variation coefficient among populations ranged from 1.86% to 10.56% while it ranged 7.38% to 19.47%within population.There were rich variation in kernel composition,too,fatty acids content ranged 1.89% to 27.82% among populations while 3.57% to 54.40% within populations.The variation coefficient of amino acid ranged 4.52% to 76.85% among populations while 11.47%to 88.17% within populations,minerals content ranged 10.02% to 22.74% among populations while 11.74% to 23.53% within populations.These characters’ differences were both significant(P<0.01)among and within populations,variance components of most characters within populations were more than that among populations,which indicates the variation within populations is the main source of variation.(2)It was announced significant effect of environmental factors on several traits of J.mandshurica.The morphological characters mainly showed the geographical variation trend from southeast to northwest,and were affected by the temperature and humidity then.The oil content of walnut kernels is sensitive to the changes of equivalent latitude and temperature.The linoleic acid content is closely related to longitude,equivalent latitude,temperature and humidity,α-linolenic acid content was closely related to altitude and temperature,the content of oleic acid was significant positively correlated with humidity.Oleic acid content was positively correlated with humidity.Different geographical and ecological factors also affect the amino acid content.The linoleic acid content is closely related to longitude,equivalent latitude,temperature and humidity,α-linolenic acid content was closely related to altitude and temperature,the content of oleic acid was significant positively correlated with humidity.The contents of amino acids are also affected by different geographical and ecological factors: Leu,Asp,Gly,Ala,Pro is closely related to the equivalent latitude,Met,Ser,Gly,Ala,His,Pro is sensitive to changes in temperature,Glu,Ala,Arg is closely related to the sunshine hours,respectively.(3)There was a significant correlation between some seed morphology and kernel composition characters of J.mandshurica,and it was significantly closely related to each other of seed morphology traits.The kernel rate was significant positive correlation with single kernel weight,while negatively correlated with fruit length,three diameter,kernel shell thickness,fruit weight and nut weight.There was a significant correlation between seed morphology and kernel composition traits in a few traits within the populations and no similar correlation pattern was found in different populations.there are different correlations among kernel components.Oleic acid is negatively correlated with linoleic acid and α-linolenic acid.It was significant closely related to each other in amino acid content traits,while not significant in vitamin contents,significant positive correlation between mineral element Mg and P,and also Fe and Zn.(4)Single trait is evaluated with populations and individuals.BLUP values of traits are standardized,weight values are assigned according to the importance of traits,comprehensive breeding values are calculated and excellent materials are selected.According to the selection rate of 20%,the single kernel weight gain was 9.60% with population selection,and 22.23%with individuals selection.Oil content was 3.90%和 9.78%,essential fatty acids is 1.19% and6.01%,essential amino acid is 7.13% and 19.53%,total amino acid is 9.35% and 21.33%,vitamin B6 is 34.62% and 34.66%,vitamin E is-7.52% and 42.45%,vitamin A is 14.82% and33.55%,Fe content is 15.15% and 32.95%,Zn content is 7.75% and 19.30%,Ca content is 14.21%and 26.46%,Mg content is 9.18% and 18.33%,P content was 11.74% and 19.97% with populations and individuals,respectively.It indicates effect of individuals selection was obviously better than population selection,and medicinal,oil and edible individuals and populations were selected out.As the 20% selection rate,the exocarp gain was 12.22% and 40.25%of medicinal populations and individuals,oil content gain was 9.83% and 24.15% of oil populations and individuals,the average gain of kernel weight,essential amino acids,total amino acids,VB6,Mg and P was 6.18%,5.00%,9.08%,-1.13%,0.20%,0.42% of edible populations,and 15.23%,13.87%,14.57%,13.49%,8.70% and 7.17% of individuals,respectively.(5)Excellent populations and individuals are selected by comprehensive analysis of morphology and kernel composition.3 evaluation methods(Brezin multi traits comprehensive assessment method,comprehensive coordinate evaluation method,comprehensive breeding value method)have different evaluation results for populations and individuals,while the comprehensive breeding value method is the best.The average gain of kernel weight,shell thickness,kernel content rate,oil content,EFA,essential amino acid,VB6、Mg、P content of3 excellent populations(YBL,JST,TL)was 3.48%,-0.67%,5.91%,1.46%,-0.95%,3.05%,0.62%、6.38%、6.19%,respectively while that was 16.44%,0.12%,12.73%,3.28%,1.27%,6.32%,1.16%、1.83% and 2.64% of 24 excellent individuals.This study revealed the pattern of variation,diversity,correlation of traits,and selection methods of single and multiple traits among populations and within populations,which could provide a theoretical foundation for further research of systematic genetic improvement of J.mandshurica.And the excellent J.mandshurica materials could be used for nut forests and breeding population construction. |
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