Genetic and Environmental Factors Shaping Cannabis Phenotypes A Study on Temperature Effects and Genetic Regulation of Anthocyanin Accumulation in Cannabis sativa

Abstract

Purple pigments found in the inflorescence of cannabis plants are a desired trait in the cannabis flower industry, contributing to market appeal, cultivar differentiation, and potentially providing added therapeutic and health benefits to consumers. Anthocyanins, the compounds responsible for purple pigments in C. sativa, provide plants with protection against various environmental stressors. The mechanisms underlying this trait in C. sativa are poorly understood and warrant investigation to facilitate the development of new cultivars with diverse pigmentation patterns, increased levels of anthocyanins, and enhanced resilience to environmental stressors. To better understand how environmental temperatures affect anthocyanin accumulation in C. sativa, temperature treatments were conducted and data on anthocyanin content, CBD percentages, and biomass yield were collected. Anthocyanin biosynthesis in the inflorescence was significantly affected by temperature, with plants grown in 8 and 15°C accumulating the highest levels of anthocyanins. Temperature treatments were also shown to effect CBD percentages and biomass yield, but contrary to anthocyanin biosynthesis, differences in these traits were likely due to differences in maturity. To better understand the genetic mechanism governing anthocyanin accumulation in C. sativa, a mapping population and an open-pollinated population were used to help identify qualitative trait loci (QTL) associated with this trait. Significant single nucleotide polymorphisms (SNPs) for flower and leaf color were found on chromosome 6 while significant SNPs for stem color were found on chromosome 8. Investigating randomly selected SNPs within the QTL regions to further elucidate the mode of inheritance of anthocyanin accumulation in C. sativa revealed both complete and incomplete dominance patterns. To achieve a comprehensive understanding of the environmental factors, genetic mechanisms, and mode of inheritance governing anthocyanin accumulation in C. sativa, it is imperative that further studies are conducted. These studies should involve expanding temperature treatments to cover wider ranges with smaller intervals, allowing for a more nuanced exploration of temperature's impact on anthocyanin accumulation. Also, creating additional mapping populations with various cultivars can provide a more comprehensive view of the genetic landscape. Furthermore, evaluating a greater number of SNPs can enhance resolution and facilitate a deeper understanding of the underlying genetic mechanisms. By integrating these approaches, researchers can advance our knowledge of the complex interplay between environmental factors and genetic traits in C. sativa.