International Journal of Molecular Evolution and Biodiversity, 2025, Vol.15, No.1, 51-63 http://ecoevopublisher.com/index.php/ijmeb 58 process involved natural selection driven by the local climate, which led to the development of distinct morphological and chemical traits. The spread of the Indica strain began with its early dissemination to Southeast Asia, Africa, and eventually the Americas. This spread was facilitated by human migration and trade routes, which allowed the strain to adapt to various environmental conditions and cultural practices (McPartland and Small, 2020). The popularity of Indica strains grew significantly in the 1980s, driven by their high tetrahydrocannabinol (THC) content and the psychoactive effects that were highly sought after for both recreational and medicinal purposes (McPartland and Small, 2020). Figure 3 Representative achenes of four varieties (Adopted from McPartland and Small, 2020) Image caption: (A) indica, Rajshahi (Bangladesh), Clarke 1877 (BM); (B) indica, Coimbatore (India), Bircher 1893 (K); (C) indica, South Africa, Hillig1996; (IND); (D) himalayensis neotype; (E) himalayensis, Bareilly (India), Roxburgh1796 (K); (F) himalayensis, East Bengal (Bangladesh) Griffith 1835 (GH); (G) afghanica neotype H afghanica epitype I afghanica Yarkant (Xīnjiāng), Henderson 1871 (LE); (J) asperrima lectotype K asperrima Nuristān (Afghanistan), Street 1965 (F); (L) Kailiyskiy Alatau (Kazakhstan), Semenov-Tyan-Shansky 1857 (LE) (Adopted from McPartland and Small, 2020) 7.2 Discuss the genetic improvements made and their impacts. Genetic improvements in the Indica strain have been substantial, particularly through the process of polyploidization. This technique involves the induction of polyploidy, which has been shown to enhance certain desirable traits in cannabis plants. For instance, the development of tetraploid Indica lines has resulted in larger fan leaves, increased trichome density, and significant changes in the terpene profile. These genetic modifications have also led to a notable increase in cannabidiol (CBD) content, which is beneficial for medical applications (Parsons et al., 2019). Moreover, the genetic diversity of Indica strains has been further enriched by cross-breeding with other cannabis varieties from different gene pools. This has resulted in hybrid strains that combine the high THC content of Indica with other beneficial traits such as improved yield and resistance to pests and diseases (Clarke and Merlin, 2016; Ren et al., 2021). The use of advanced genomic techniques, such as whole-genome resequencing, has provided deeper insights into the genetic makeup of Indica strains, enabling more targeted breeding strategies to enhance specific traits (Ren et al., 2021). These genetic improvements have had significant impacts on both the medical and recreational cannabis markets. The increased CBD content and optimized terpene profiles have made Indica strains highly desirable for therapeutic uses, including pain relief, anxiety reduction, and anti-inflammatory effects. On the recreational side, the high THC content and unique flavor profiles have continued to drive the popularity of Indica strains among consumers (Parsons et al., 2019; Romero et al., 2020).
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