• Journal of Korean Society of Forest Science
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• v.66 no.1
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• pp.109-117
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• 1984

Allozyme study for open pollinated seeds of forty nine pitch pine families in an $F_1$-hybrid seed orchard demonstrated that allozyme variants in aspartate aminotransferase(AAT), glutamate dehydrogenase(GDH) and leucine aminopeptidase(LAP) systems are encoded by at Least eight loci; five for AAT, one for GDH and two fur LAP. Allozyme variations showed polymorphisms at seven of the eight loci, except GDH. Average number of alleles examined over six loci were 2.33 and 2.67 for maternal and progeny groups, respectively. Average heterozygosity and genetic diversity computed over six loci were, respectively, 0.235 and 5.409 for maternal tree group, 0.238 and 5.569 for progeny group. The proportion of $F_1$-hybrid seeds estimated by allozyme analysis was 0.77%. The estimated proportion of $F_1$ hybrid seeds by allozyme study is in good agreement with the value 0.73% estimated by morphological study for the proportion of pitch ${\times}$ Loblolly $F_1$ hybrid seedlings at a nursery. Indications for Wahlund effect, high levels of self-fertilization and for non-random matings in the $F_1$ hybrid seed orchard call for cautions in estimating allele frequency changes and mating probabilities for the parental and progeny groups.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.31-36
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• 1983

Flowering time of Pinus rigida Mill and Pinus taeda L, in an $F_1$-hybrid seed orchard was investigated for five years from 1971 through 1975. The two tree species flowered during late April to early May at the observation site, Flowering patterns of the two species of different sex of the same species changed yearly during the five observation years. Floral development of the two species appeared to depend largely on temperature factor during the period of the initiation of floral organs up to flowering provided that other environmental factors are normal. Six-days difference in flowing time between female inflorescence of pitch (flower later) and male inflorescence of loblolly (flower earlier) pines effectively isolated the two species reproductively on population levels. Not all of selected trees of the two species for their synchronized flowering appeared to be useful as parental trees for the establishment of $F_1$-hybrid seed orchards. With the result from this investigation the author suggested to use a modified simple recurrent selection method for pitch-loblolly hybrid pine breeding.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.532-538
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• 1996

GA4/7 spray, injection and several cultural treatments were applied to the greenhouse-grown potted hybrid larch(Larix decidua${\times}$leptolepis) grafts and field-grown European larch seedlings to induce early flowering. A treatment consisting of repeat-ed GA4/7 sprays, alone, was the most effective flower induction treatment for greenhouse-grown, potted larch grafts. Root pruning as a adjunct treatment did not show synergistic effects. Injection for potted grafts with GA4/7 was not useful approach in this study and it resulted in increased mortality. In the field experiment with 10-Year-old larch seedlings, repeated GA4/7 sprays in combination with root pruning or with plastic mulching appears to be useful and practical means for inducing larch flowers:

• Journal of Plant Biology
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• v.11 no.1
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• pp.27-32
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• 1968

In the present experiment as a basic study for establishing a hybrid seed orchard, an observation was made on the survivability of grafts using Pinus rigida as the stock and its hybrids as the sciion, and on the shape and germination of pollen collected from grafted plants. The results are summarized as follows: 1. The hybrid scion of P. rigida.taeda or $P. rigida{\times}(P. rigida.taeda)$ grafted into P. rigida stock showed lower survivability than the homoplastic graftings of P. rigida. 2. Five among the eight eleven-year old scions homoplastically grafted into two-year old stock for the staminate strobile one year after their grafting. 3. There was no difference in the size and germination ability between the pollen collected from homoplastically grafted plant and from the normal one. 4. The pollen collected from the grafted plant is thought to be usable for the control pollination as the germination of such pollen was considerably good.

• Journal of Korean Society of Forest Science
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• v.62 no.1
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• pp.82-86
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• 1983

Cone and seed development after self-pollination in 14-year-old Pinus rigida Mill. was investigated in an $F_1$-hybrid seed orchard that consists of Pinus rigida Mill. and Pinus taeda L. in alternative rows. On an average, 83.8% of the self-pollinated receptive female strobili developed into cones. This value appears to be normal compared to cone development after open-pollination in other pine species such as in Pinus sylvestris L. However, there was a great variation in filled seed development after self-pollination among the investigated individual trees (Table 1-1). The 34.5%, a ratio of filled seeds after self-pollination was significantly lower than 91.7%, that by the open-pollination. Some of the investigated trees developed 70.0%-83.5% of filled seeds after self-pollination. Thus, those are not desirable as trees for seed parent in establishing $F_1$-hybrid seed orchards in future. A further study on the rate of filled seed development by various pollination systems consisting of self-pollination, self-and cross-pollination with intraspecific, mixed (tree's own and foreign pollens) pollens and cross-pollination with interspecific, mixed pollens of the two parental tree species is necessary to determine the quality of seed parent trees in establishing $F_1$-hybrid seed orchards.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.239-249
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• 1982

The outlines of superior stands, including species mixed, age classes, canopies, and ecological conditions of the stands, were examined in the forests of west Germany, Sweden, and Netherland. The establishment schemes of tree seed orchards for the production of high genetic quality seed were also investigated in the present study. 1. The meteorological conditions, abundant in precipitation and high in relative humidity, prove it to be oceanic climate characteristics in the Scandinavia located in high latitude and north-western part of Europe. The photo periodical characteristics following to day-length and the frost times determine the patterns of tree growth and distribution as well as the tree adaptability due to bud-setting and bud-flushing in Sweden forest. 2. The European forests are generally characterized by dense multistoried forest type composed of upper stories of tall tree species such as Norway spruce, fir, Scots pine and beech, lower stories of shade tolerant poles and saplings of spruce, fir, beech, and floor vegetations covered with birch, oak and hornbeam etc. 3. The single tree selection method and group shelterwood method are commonly applied for silvicultural system but shelterwood method and clearcutting method practiced partially in limited area. Badischer Femelschlagbetrieb and Bayerischer Femelschlagbetrieb are popularized to the regeneration of Schwarzwald but selection method applied in part. 4. Tree cuttings are properly limited so as not to exceed annual increment volume for the sustained yield and the preservation of ecosystem in European forest management. Land preservation and recreation function are more interested with the promotion of wood production in the forest management. 5. Careful attentions are paid to the reforestation of the introduced exotic species, such as Douglas-fir, red oak, pines from America, Japanese larch, Italian poplar etc., with concern against the insect and pest damage, and the meteorological damage. 6. Some intensive studies on tree improvement, such as selection of plus tree, selection of plus stand for seed collection, provenance trial, progeny test of clone, hybrid seed orchard for clone complexing, are performed in the countries and the great part of the seed required for reforestation are supplied from the seed orchard established in Sweden and Netherland.

• Journal of Korean Society of Forest Science
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• v.29 no.1
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• pp.102-114
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• 1976

This experiment was conducted to investigate the percentage of fertile seed in terms of crossabilities and relationships of taxonomic affinities for the ${\times}$ P. rigitaeda of interspecific hybrid, ${\times}$ P. rigida rigitaeda and ${\times}$ P. rigitaeda rigida of backcross hybrids, $F_2$ of ${\times}$ P. rigitaeda and natural hybrid of ${\times}$ P. rigitaeda within Sub-genus Diploxylon of the Genus Pinus. The possibility of establishment of hybrid seed orchard and differentia of hybrids for the purpose of extensive program of reforestation in the future have also been investigated. And, the experimental results obtained are summarized as follows: 1. On the basis of crossabilities as well as on the taxonomic affinities according to the systems of Shaw, Pilger and Duffield, it has been proven that the parental species of those hybrids are of close affinities and range of the fertile hybrid seed production rate was as high as 67-87% in the best hybrid combination (Table 6). 2. Those hybrids seemed to be most promising in the growth perfermance exhibiting 28-80% more volume growth compared to the P. rigida with the statistic significance of 1-5% level (Table 7, 8, 9). And all hybrids exhibit cold hardiness as much as P. rigida except $F_1$ hybrid of ${\times}$ P. rigitaeda and it seems to suggest that the characteristics of cold hardiness were transmitted from the P. rigida. 3. With regard to the anatomical characteristics of needle, the hypoderm is biform in most of the hybrid pines and the characteristics of resin canals are medial in all hybrid. And, the fibrovascular bundles are intermediate of both parent in all hybrid. Therefore it was found to be possible to distinguish the hybrids pines from their parents by the needle characteristics (Table 10). 4. It has been demonstrated that the hybrids pines have a phenolic substance (No. 7) of pale yellow at Rf-0.66, same as P. rigida, but no trace of phenolic substance was observed in the P. taeda. This fact will serve as an important criteria for early identification of hybridity in progeny testing (Table 11). 5. It was found to be possible to distinguish by the starch gel electrophoretic variations banding patterns and staining densities of isoperoxidase in the needles of the hybrids pines from their parents (Fig. 1).

• Journal of Korean Society of Forest Science
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• v.16 no.1
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• pp.1-32
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• 1972

By means of the interspecific hybridization in the Sub-genus Diploxylon of the Genus Pinus, $F_1$ hybrids of Pinus rigida${\times}$elliottii, Pinus rigida${\times}$radiata, P. rigida${\times}$serotina and P. densiflora${\times}$thunbergii had been produced. And on the basis of the crossabilities of these hybrids the taxonomic affinities of these pines were examined. And the needle characteristics of these hybrid and the occurence of phenolic substances in these $F_1$ hybrid were also investigated to see the potential usefulness of these characteristics for the diagnosis of the taxonomic affinity. And, the growth performances of the $F_1$ hybrids have also been compared with those of parental species. In order to contribute to the establishment of the hybrid seed orchard the introgression phenomena between P. densiflora and P. thunbergii in the eastern coastal area have also been investigated along with the investigation of the heterozygosity of plus trees of P. densiflora growing in the clone bank in Suwon. And the results were summarized as follows. 1. On the basis of crossabilities as well as on the taxonomic affinities according to the systems of Shaw, Pilger and Duffield, it has been proven that the parental species of those hybrids are of close affinities and range of the fertile hybrid seed production rate was as high as 28-58% in the best hybrid combination (Table 13). 2. Among those hybrids, the ${\times}$ Pinus, rigiserotina hybrid seemed to be most promising in the growth performance exhibiting 109-155% more volume growth compared to the seed parent with the statistic significance of 1% level (Tables 16 and 17). 3. Notwithstanding the fact that the all of the pollen parents are cold tender, all hybrids exhibit cold hardiness as much as their seed parent and it seems to suggest that the characteristics of cold hardiness were transmitted from the seed parent. 4. Though a striking difference in needle length was observed between the parental species of each hybrid, it was difficult to distinguish each hybrid from their seed parent by the needle length except ${\times}$P. rigiserotina which is characterized by long needle which is 65% more longer than the needle of the seed parent (Table 21). 5. With regard to the anatomical characteristics of needle, the hypoderm is apparently thicker in most of the $F_1$ hybrid pines and the characteristics of resin canals are dominated by medial in most $F_1$ hybrid. And, the fibrovascular bundles were apart as were in their seed parent. Therefore it was found to be possible to distinguish the hybrids pines from their parents by the needle characteristics. And, it is to be noticed that the ${\times}$P. densithunbergii was more close to the pollen parent having RDI value of 0.73 (Fig.l, Table 22). 6. It has been demonstrated that ${\times}$P. rigielliottii, ${\times}$P. rigiradiata and ${\times}$P. rigitaeda have a phenolic substance (No.7) of light yellow at Rf-0.46, same as their seed parent, but no trace of phenolic substance was observed in their pollen parent. This fact will serve as an important criteria for early identification of hybridity in progeny testing. However, the fact that both of ${\times}$P. rigiserotina and ${\times}$P. densithunbergii exhibit the same reactions of phenolic substances as well their parental species seems to indicate the close affinities between the parental species of the respective hybrid (Fig.2, Table 23). 7. The separation and the reaction of phenolic substance developed on TLC were found to be same in the same species showing no variations between the individuals, and no variations due to tree part of sampling, tree age or pollen sources. And the reaction was also observed regardless of the not varied by the kind of developing solvent whether it is Aceton-Chloroform (3:7 v/v) or Benzene-Methanol-Acetic acid (90:16:8 v/v). 8. The introgression phenomena of natural Pinus densifiora stand in both east and west coastal area indicates that the major part of the red pines investigated are all heterozygous and the heterozygosity of pines are higher in the west coast than in the east coast(Tables 24 and 25). 9. Based on the RDI, among the plus trees of Pinus densiflora selected in Korea and Japan as well, no pure P. densiflora has been found. Since all of the sample trees of Pinus densiflora were found to be as heterozygous bearing part of the characteristics of P. thunbergii, those red pines were considered to be natural heterotic hybrid pines(Figs. 3 and 4. Tables 26 and 27).