The Factor Analysis And Countermeasures To Low Seed-production In Seed-orchard Of Huabei Larch

Because of cold-resistance and adaption,Huabei larch has the highly value in use.The seed-orchard of Huabei larch provides fine sowing quality and genetic quality seeds, but those seed-yields was low and planting character was bad ,those deterrented its progress for a long time.So in order to improve producing efficiency,based on genetic basis. This paper discussed genetic variance, correlance between seeds and the other traits, the standard of plus trees selection , pollination methods and the cross between Huabei larch and Larix kaempferi. These were the results:(1) Because of high variation of the yields.Genetic controlling was the intrinsic factors for the variation of the yields. Although coming from different regions and clones,the clones effects were mightily notability,so the diversity existed impersonally.The high burliness clones were in low side and mostly were in low yields.The internality factors of clones' burliness were genetic basis.(2) The yields should be part of the side of the seletion of superior trees.The female flowers had the indistinctly correlation with tree height, chest diameter, form quotient, volume of wood, mid-diameter, timber height, crown breadth, volume of crown and especially it had higher positive correlation with tree height and timber height.The number of seeds had distinctly correlation with chest diameter, mid-diameter, crown breadth and weight of branch sterm,morever it had remarkable positive correlation with weight of simple fruit.Tht path analysis suggested the traits such as denstity of wood, chest diameter, crown breadth, important branch sterm had positive effects to the number of seeds,especially denstity of wood and chest diameter and the traits such as weight of branch sterm, mid-diameter, weight of simple fruit, tree height,especially weight of branch sterm and mid-diameter.So, it was illogically that the criterions for the selection of superior trees were only form quarlity and growth targets.(3) The efficiency of selection of the yields suggested it was not a good idea for indirect selection of seed output an the seed output was recommendated to select by direct method.(4)Based on the small part of clones controlling the yields of the seed-orchard,the portential for selection of yieds was high.The results of stability of yieds suggested the best clone was Yin 02,next were Yin03, Bei12, Bei09, Bei14, Bei20, Yin04.(5) As to the inseminating-modes,the intraspecies mixed-pollen were the best mode,next were species hybridization, open pollination, self-pollination, assistant self-pollination;The...