An Overview of the Practices and Management Methods for Enhancing Seed Production in Conifer Plantations for Commercial Use

Abstract

Flowering, the beginning of the reproductive growth, is a significant stage in the growth and development of plants. Conifers are economically and ecologically important, characterized by straight trunks and a good wood quality and, thus, conifer plantations are widely distributed around the world. In addition, conifer species have a good tolerance to biotic and abiotic stress, and a stronger survival ability. Seeds of some conifer species, such as Pinus koraiensis, are rich in vitamins, amino acids, mineral elements and other nutrients, which are used for food and medicine. Although conifers are the largest (giant sequoia) and oldest living plants (bristlecone pine), their growth cycle is relatively long, and the seed yield is unstable. In the present work, we reviewed selected literature and provide a comprehensive overview on the most influential factors and on the methods and techniques that can be adopted in order to improve flowering and seed production in conifers species. The review revealed that flowering and seed yields in conifers are affected by a variety of factors, such as pollen, temperature, light, water availability, nutrients, etc., and a number of management techniques, including topping off, pruning, fertilization, hormone treatment, supplementary pollination, etc. has been developed for improving cone yields. Furthermore, several flowering-related genes (FT, Flowering locus T and MADS-box, MCMI, AGAMOUS, DEFICIENCES and SRF) that play a crucial role in flowering in coniferous trees were identified. The results of this study can be useful for forest managers and for enhancing seed yields in conifer plantations for commercial use.

Is Pollen Production of Birch Controlled by Genetics and Local Conditions?

“…Effects on pollen production and catkin formation were especially obvious two years after topping. Topping and pruning have been considered as adequate tree crown management techniques to enhance seed production, specifically in conifer seed orchards, or to promote the branching of the trees [47,68,69]. Viherä-Aarnio and Ryynänen [47] studied seed production of silver birch individuals that were topped in the second year in a greenhouse experiment.…”

Genotypic and environmental effect on male flower production in Cupressus sempervirens clones and selection of genotypes with reduced pollen emission

“…These conditions may have promoted flower initiation and bud differentiation in the summer of 2013 (which was particularly rainy) and the subsequent development of cones up to full flowering in the winter of 2014. Some authors in fact have reported a positive effect of watering during the growing season on the production of pollen cones in pine species ( Puritch, 1977 ; Li et al., 2021 ). The climatic conditions in 2014 could represent a sort of stress test for assaying the production of male cones by common cypress clones in a particularly conducive environment.…”

Transcriptomic Analysis of Hormone Signal Transduction, Carbohydrate Metabolism, Heat Shock Proteins, and SCF Complexes before and after Fertilization of Korean Pine Ovules

“…For example, the application of nitrogen fertilizer has been shown to promote seed setting and increase female blossom bud numbers. The application of GA 3 has also been shown to significantly increase the number of female and male Korean pine blossom buds [ 6 ]. Research on Korean pine reproductive biology has mostly focused on issues such as ovule failure and poor fertilization, which hinder seed production [ 7 ].…”