Addressing microbial-induced pre- and post-harvest quality reduction in cannabis

随着大麻(大麻)于2018年10月在加拿大合法化，用于医疗和娱乐市场的干大麻花(花蕾)和大麻衍生产品的生产和供应有所增加。大多数大麻生产(90%)发生在温室里，每个作物周期需要10周的收获期。收获后，大麻花被干燥到水分含量(按重量计)10-12%。持证生产者(LP)面临的最大挑战是由于微生物和病原体入侵花卉造成的采前和收获后的损失，以及由于环境扰动而无法预测的花卉质量。此外，病毒病原体的日益流行正在造成迄今尚未确定的质量损失。酵母和霉菌总数(TYM)水平是决定大麻产品最终价值的关键因素--生产过程中的高水平微生物可能导致产品降级或拒收，可能导致每年数百万美元的损失。此外，由于环境胁迫、疾病或采后损害导致的花发育不良，可能会降低花的质量以及毛状体中药物和精神药物的含量。很难对收获前和收获后的花朵质量进行测量，因为还没有开发出适当的方法来评估它们。拟议的研究将提供一些重大科技进步，可作为提高加拿大大麻质量的创新工艺和技术，具体如下：(1)可预测的栽培和分子方法，以估计大麻生产设施中的伤害量，以指导生产者优化利用资源，将收获后的损失降至最低；(2)确定环境条件、大麻基因型和收割后处理方法，将伤害量降至最低；(3)以毛状体成熟分析为基础的计算机辅助目视方法，以评估最佳的花卉质量；(4)更好地了解大麻中的复杂病毒病。加拿大各地的其他研究机构和大麻生产商可以利用一些新的研究方法造福加拿大人，这将是这一为期3年的研究项目的重要成果。

Following legalization of cannabis (Cannabis sativa L., marijuana) in Canada in October, 2018, production and supply of dried cannabis flowers (buds) and cannabis-derived products for medicinal and recreational markets have increased. Most cannabis production (90%) occurs in greenhouses, and each crop cycle requires a 10 week period to harvest. After harvest, cannabis flowers are dried to a moisture content of 10-12% (by weight). The greatest challenge facing licensed producers (LPs) is pre-and post-harvest losses due to microbial and pathogen invasion of flowers and unpredictable flower quality due to environmental perturbations. In addition, the increasing prevalence of viral pathogens is causing as-yet-undetermined losses in quality. The total yeast and mold (TYM) levels is a critical factor for final value of cannabis products - high levels of microbes during production can result in downgrading or rejection of product, potentially leading to millions of dollars in losses annually. In addition, poor flower development due to environmental stress, diseases or post-harvest damage can reduce flower quality and levels of medicinal and psychotropic chemicals in trichomes. Measurements of pre-and post-harvest flower quality are difficult to make as appropriate methods have not been developed to assess them. The proposed research will provide a number of significant scientific and technological advancements that can be implemented as innovative processes and technologies to improve cannabis quality in Canada, as follows: (i) a predictable culture and molecular based method to estimate TYM in cannabis production facilities to guide producers in optimal usage of resources to minimize post-harvest losses; (ii) identification of environmental conditions, cannabis genotypes and post-harvest handling methods that minimize TYM; (iii) a computer-assisted visual method based on trichome maturation analysis to assess optimal flower quality; (iv) a better understanding of the viral disease complex in cannabis. A number of novel research methodologies that can be utilized by other research institutions and cannabis producers across Canada to benefit Canadians will be an important outcome of this 3-year research project.