In vitro micropropagation is an important technique for coffee multiplication performed by somatic embryogenesis, which can be indirect, with the formation of calluses, or direct, when embryos are formed directly from explant cells. In the present study, we characterized the ontogenesis of somatic embryos regenerated via indirect and direct somatic embryogenesis in leaf explants from Coffea arabica ‘Mundo Novo’ and assessed the development of these embryos in leaf explants from adult plants maintained ex situ and in vitro. Anatomical analyses showed that leaf explants present structural differences depending on their origin. In the direct pathway, tissue develops more rapidly in explants from in vitro plants than in those from ex situ explants. In both methods, the formation of a pro-embryogenic mass was found to be essential for embryo formation. In the indirect pathway, calluses from ex situ material presented elongated cells and a loose external appearance. Conversely, calluses from in vitro material presented large regions of meristematic cells with a single large nucleus and dense cytoplasm. We propose that indirect somatic embryogenesis in in vitro–grown explants may accelerate genetic breeding in coffee, and it represents the most efficient condition for somatic embryogenesis, producing embryos in less time than the required by ex situ plants (indirect: 260 d in ex situ conditions, 62 d in vitro; direct: 270 d ex situ, 86 d in vitro).

体外微繁殖是通过体细胞胚胎发生进行咖啡繁殖的一项重要技术，这可以是间接的，形成愈伤组织，也可以是直接的，当胚胎直接从外植体细胞形成时。在本研究中，我们表征了通过间接和直接体细胞胚胎发生再生的体细胞胚胎的个体发生，在来自小粒咖啡'Mundo Novo' 的叶外植体中，并评估了这些胚胎在来自异地和体外维持的成年植物的叶外植体中的发育。解剖学分析表明，叶外植体根据其来源存在结构差异。在直接途径中，组织在来自体外的外植体中发育得更快植物比那些来自异地外植体的植物。在这两种方法中，都发现促胚团的形成对于胚胎形成是必不可少的。在间接途径中，来自异位材料的愈伤组织呈现出细长的细胞和松散的外观。相反，来自体外材料的愈伤组织呈现出具有单个大核和致密细胞质的大面积分生组织细胞。我们建议体外培养的外植体中的间接体细胞胚胎发生可以加速咖啡的遗传育种，它代表了体细胞胚胎发生的最有效条件，在比异地植物所需的时间更短的时间内产生胚胎（间接：异地260 天）条件下，体外62 天；直接：270 d易地，86 d体外）。