Study on hybridization among exotic pines and their early growth assessment of F1 generation.
The breeding and hybridization among exotic pines were studied in this paper. Eight F1-hybrids of Pinus elliottii var. elliottii (PEE) × Pinus caribaea var. hondurensis (PCH) and 47 F1-hybrids of Pinus taeda (PT) × Pinus caribaea var. hondurensis (PCH), which were selected from 17 crosses of PEE × PCH and 75 crosses of PT × PCH according to the order of seedling height, were grown for filial generation test in randomly block design. The height of all the trees were measured at ages 3 and 5 years. The results of variance analysis (ANOVA) revealed that there were no differences among the hybrids in terms of the average height at age 3 years because of the lower cold-endurance of some young trees, but significant differences appeared at the age of 5 among the crosses, especially the growth differences of PT × PCH crosses were extremely significant. Thus, the assessment of F1 hybrids would begin 4 years after planting in the fields. The height of better F1 families of PT × PCH were higher than 4.0 meters, which exceeded the national standard for good conifer trees. In conclusion, better pine varieties can be selected effectively through hybridization in exotic pines.