×PINUS RIGIRADIATA의 交配親和力과 特性에 關한 硏究 = Studies in the crossabilities and principal characteristics of Pitch-Monterey hybrid pine (×P. rigiradiata)

다국어 초록 (Multilingual Abstract)

This experiment was conducted to investigate the percentage of fertile seed in terms of crossability and relationship of taxonomic affinity for the xP. rigiradiata of interspecific hybrid within Sub-genus Diploxylon of 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. the experimental results obtained are summarized as follows:
1. Since the percentage of sound (fertile) seed of xP. rigiradiata that is a F_1 hybrid between seed tree P. rigida and pllen tree P. radiata was relatively high, it would be apparent that the crossability of both trees is high and closely related.
2. The growth rate (i.e., stem height, diameter at stem base and volume) of xP. rigiradiata has shown to be slow and has indicated that xP. rigiradiata would be more closely related to the P. rigida.
3. In the anatomical characteristics, the position of fibrovascular bundle of xP. rigiradiata was close together as seen by P. radiata and the position of resin canal was medium as affected by the character of P. rigida.
4. The cold hardness of xP. rigiradiata was distinctively better than P. radiata. From this it is concluded that the cold hardness of xP. rigiradiata has been affected by the P. rigida.
5. In the conclusion xP. rigiradiata would not be a usable tree for the use in reforestation purpose, since growth rate of this tree is no better than P. rigida. However, further study will have to be made to obtain detailed data on this subject.