Selection Of Superior Families For Seed Orchard Of Larix Principis-rupprechtii

The seed orchard of Larix principis-rupprechtii is a seed base with excellent seed sowing quality and genetic quality,but for a long time,development of seed orchard has been plagued by poor quality and low production.If the excellent strains can not select early,it will result in a huge waste of manpower,material and financial resources.Therefore,seed quality,half-sib progeny growth and genetic differences were studied to improve the production efficiency.Results showed that there were significant difference in seed production,half-sib progeny growth and genetic of Larix principis-rupprechtii.The results in detail are as follows:1.There were significant difference in thousand seed weight,overall seed rate,standard branch seed yield,germination potential,germination rate etc among different strains of the first generation of Larix principis-rupprechtii.Thirty-three superior strains(136,38,25,7,16,112,6,18,13,108,106,52,48,42,43,111,56,47,71,49,12,5,30,93,98,62,119,79,67,101,57,124,69)were selected by membership-function integrated seed quality of each strain.2.Significant difference in half-sib progeny of each strain at DBH,height and volume were also found,indicating that excellent strains can be selected by growth traits of half-sib progeny.The average volume of 138 half-sib progeny was 0.27m3,there were 57 strains higher than the average.Genetic gain in volume of half-sib progeny can be reached at 39.55 % when the selection rate was 30%.3.The RNA-seq sequencing of male and female strains showed that there was a significant difference between NO.10 strain(the most flowering)and NO.6 strain(the less flowering).There were 7 085 differently expressed genes between NO.6 and NO.10 female flowers,which had 4 954 up-regulated genes and 2 131down-regulated genes.While,the male flowers of those two strains had 7 489 differently expressed genes,in which the number of up-regulated genes was 5 110,the number of down-regulated genes was 2 379.