Abstract:

Sowed seedlings of Larix olgensis were not planted in the field until they were transplanted for another year in the nursery. Because their size differentiated severely, sowed seedlings should have graded prior to transplanting in order to cost saving for irrigation and fertilization during subsequent culturing. Using principal component analysis, the grading standards were determined as diameter, the number of first-order lateral root>5 cm in length at junction, and the number of lateral root>1 cm in length. The ratio of I, II, III, and IV was 2.2%, 14.8%, 29.6%, and 53.4%, respectively. When they were transplanted, survival for these seedlings based on the grading standards was 80.0%, 70.1%, 60.8% and 55.0%. And significant differences in survival among the seedlings were found. Thus, the sowed seedlings should be graded prior to transplanting and could be graded into 4 classes based on these grading standards. Furthermore, the standards proved to be feasible and operational according to transplanting test.