Effects of Fertilization on Cone and Seed Morphological Characteristics in Larix Kaempferi Seed Orchard

Larch is one of the most important tree species for industrial afforestation in China, and its production is related to the development of larch plantation industry. In order to effectively improve the seed yield of Larix kaempferi seed orchard and meet the demand for improved larix seed varieties in production, the 1.5 and 2 generation seed orchard of Larix Kaempferi was taken as the research object in this study, and N fertilizer, P fertilizer and K fertilizer were applied as fertilizers, and orthogonal experimental design was adopted. The effects of fertilization treatment on cone and seed characteristics of parent tree of Larch seed orchard were investigated and analyzed. The results show that: In terms of cone characteristics, fertilization significantly increased the weight of single fruit, the longitudinal diameter of cone and the transverse diameter of cone in 1.5 and 2 generations of Japanese larch seed garden. In 1.5 generation seed garden, the weight of single fruit and the longitudinal diameter of cone were the largest under "N (0.4 kg/plant) + P (0.6 kg/plant) + K (0.6 kg/plant)" treatment.The transverse diameter of cone treated with "N (0.2 kg/plant) + P (0.6 kg/plant) + K (0.4 kg/plant)" was the largest, reaching 2.26 cm, which was 1.1 times that of CK. In the second generation seed garden, the weight of single fruit, longitudinal diameter and transverse diameter of cone under "N (0.2 kg/plant) + P (0.8 kg/plant) + K (0.6 kg/plant)" treatment were higher, reaching 8.23 g, 3.74 cm and 2.58 cm, respectively.In terms of seed characteristics, the effects of fertilization on seed shape and quality indexes of 1.5 and 2 generations of Larch were limited, and fertilization only had significant effects on longitudinal diameter, transverse diameter and lateral diameter of seeds in 1.5 generations of seed orchard and 1000-grain weight in 2 generations of seed orchard. In conclusion, higher K fertilizer and appropriate N fertilizer application rate are conducive to the growth of cones and seeds. The optimal fertilization scheme for Japanese Larch seed orchard is 0.4 kg/plant for N fertilizer, 0.6 kg/plant for P fertilizer and 0.6 kg/plant for K fertilizer. This study has important theoretical and practical significance to guide the rational fertilization of larch seed orchard and promote the increase of seed orchard.