| Pinus Tabulaeformis Carr is the major tree species for afforestation and timber native in China. The seed orchard was a special artificial forest built according to superior clones and families. It is aim at productive superior genetic quality and sowing quality seeds. Our country began to systematic research genetic improvement of Pinus tabulaeformis in the early 1970s. At present, shannxi province have built 138.61hm2 clone seed orchard of Pinus tabulaeformis, but the low production yield and non-stablized fruiting have presently become the important problem that needs urgent solutions. A good many scholars of China and abroad have studied on improvement on seed quantity and quality of clone seed orchard of Pinus tabulaeformis. Many factors influencing the yield and quanlity of seed orchard, the main factors are genetic and environment. Study on flowering and fruiting of clone is the basic practice of management and administration of seed orchard. At the same time, it is also the key technique of seed orchard. Improvement of seed quantity is a central task of technique of seed orchard. Clone selection, thinning, fertilization, artificial pollination, soil management, control seed and cone insects are the key techniques of improvement on seed quantity and quality. Mastery and comprehend flowering and fruiting characteristics, flowering phenology of clones, fruit debelopment are much more important link in establishment and management of seed orchard and progeny test.The flowering and fruiting characteristics and hormone treatment promoting flowering of clone seed orchard of Pinus tabulaeformis two zones in Luonan Gucheng farm clone seed orchard of Shannxi province, were studied. The researches includes flowering and cone development process and flowering phenology regularity, analysis of female,male flower and 2-year-old cone strobilus differences, the growth, strobilus yield investigation, female, male flowers and 2-year-old cone strobilus space distuibution, relative analysis of clones in female and male strobili yield, 2-year-old cone, breast diameter, height and crown size, the hormone 6-BA, CCC, GA4+7different pretreatment group of concentration and treating time on Promoting flowering of Clone Seed Orchard of Pinus tabulaeformis, The main results were as follows: (1) The difference between strobilus production of the clone female and male flowers, 2-year-old cone, height and crown size is remarkable; the difference within strobilus production of the clone the male flowers is extremely remarkable, but the difference within strobilus production of the clone the female flowers and 2-year-old cone is inconspicuous. The difference between strobilus production of female flowers in the north and south branch on one clone and on the 2-year-old cone was significant, but the difference of strobilus production of male flowers in north and south branch on the one clone is not remarkable.(2) There was significant positive correlation among male strobilus production,2-year-old cone strobilus production and height. The male strobilus production was significant positive correlation with crown size. The height was extremely significant positive correlation with breast diameter and crown size. There was significant positive correlation between breast diameter and crown size. According to character of the female strobilus production, 2-year-old strobilus production,the tree high, the tree diameter at chest height, the crown size ,etc. Six clones of No.285, No.273, No. 291, No.10, No.266, No.289 were choose by characteristics of breeding value basedon ranking(CICR).(3) The male strobilus production was distribution 11-15 wheels in the crown,they have occupied 63.86%.The female strobilus and 2-year-old strobilus production was distribution 6-10 wheels in the crown. The quantitative distribution of female and male strobilus in the longitudinal section o were main borne outside of the crown, there were less distribution inside of the crown. The main distribution of male strobilus in the all directions(east, south, west and north)have not difference, but the sequence was south, west, east and north. There are difference of the distribution of female strobilus and 2-year-old cone strobilus in all directions.(4) Three kinds of hormone are great promoting effects on female strobilius production and male strobilus production in clone seed orchard. The significant difference among of clone seed orchard of Pinus tabulaeformis in different hormone promoting female strobilius production and male strobilus production. Duration of treatments such as 6,7,8 months had significant difference in promoting female strobilus production, the most effect was June and then July , August, and there are significant difference between June and August. But three times have not significant difference promoting male flowers strobilus production.(5) GA4+7 was the most effect on promoting female strobilus production in three kinds of hormone, and then 6-BA, CCC. There are significant difference between GA4+7 and other two kinds of hormone. Three treatment and different hormone concentration have significant difference in promoting female and male strobilus production. On the promoting female strobilus production, the most effect concentration was 500mg/L, and then 250mg/L, 1000 mg/L, and the 500mg/L have significant difference between other two concentration. On the promoting male strobilus production, the most effect concentration was 1000mg/L, and then 500mg/L, 250 mg/L, and three concentrations have not significant difference.
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