Pinus rigida x taeda의 F₂ 利用可能性에 關한 硏究

The Possibility of F₂ Utlization of Pinus rigida x taeda

In the Pinus rigida x taeda hybridization program in Korea, the feasibility of F₂-utilization has been examined. And following facts have been proved. 1) In the performance of fertilization and seed yield based on the results of control pollinations carried out over a decade, conelet drop after pollination is lower and the fertile seed yield is apparently higher in the F₂-than in the F₁-crossings. 2) In the growth performance of both 1-0 and 1-1 seedlings at the nursery, the F₂ is not at all inferior to the F₁. However in the field performance, the growth achievements of the F₁. the F₂ and the F₁ x wind are altered due to the site condition. 3) In the field growth performance, too, the F₂ is not at all inferior to the F₁ in the growth performances in the southern latitude (south of 35° 00 N) of south Korea, where the winter is mild enough so that the F₂ suffers no cold damage, and in such region the utilization of the F₂ is quite feasbile giving better seed yield than the F₁ and reveal ing growth superiority similar to the F₁. 4) In the area of the middle and the northern latitude of south Korea the F₂ is not much inferior to the F₁ in growth, and it is considered that the utilization of the F₂ for these area is still recommendable for practical use due to the high seed yield. 5) On the poor hill sites in the northern latitude around Suweon (37° 15 N), it is considered that the F₁ x wind is more recommendable for practical use due to the very high seed yield and high resistancy to the poor soil. It is concluded that in the pine hybridzaiton program aiming at the combining of desirable traits of different species based on the high combining ability between species, the F₂ can be utilized favorably .in the area where the environment is favorable.