Abstract: Journal of Agricultural, Earth and Environmental Sciences

Abstract:
Somatic embryogenesis has been used to produce different coffee varieties using auxin-cytokinin interaction. The procedure has been used to multiply millions of coffee plantlets worldwide although its success relies on a particular genotype. Despite the significance of auxin-cytokinin interaction in Coffea arabica micropropagation, little is known about their ability to promote callus-induced plantlets from C. arabica var Geisha (Geisha) and improved N39-6 hybrid in vitro. Thus, this study evaluated the potency of auxin-cytokinin interaction using Geisha and N39-6 coffee leaf explants. Geisha and N39-6 leaves were sterilized,excised into small fragments of around 1 cm2. These fragments were then cultured on Murashige and Skoog (MS) with different concentration of 2,4-D, 2 iP, BAP, and sucrose to activate indirect somatic embryogenesis. Media with 0.5 mg/L 2,4-D and 2 mg/L 2iP promoted callus cell formation around the leaf regions, and the percentage of the area covered by callus cells was significantly higher in Geisha scoring 76-100% (46.3) compared to 76-100% (31.3) of N39-6 within 30 days. Then, callus-formed explants transferred on 1 mg/L 2,4-D and 4 mg/L BAP developed into friable and compact calli on Geisha and N39-6 explants respectively. However, N39-6 calli was heavier (172g) unlike Geisha (163.5g). Friable and compact calli established on the media supplemented with BAP 1.125 mg/L promoted the formation of globular, torpedo, and heart-shaped embryos in both explants. The MS media containing 1.125 mg/L BAP and 0.01 mg/L Biotin advanced to the cotyledonary stage and produced roots in Geisha and N39-6 somatic embryos. The fully formed plantlets adapted well to the ex vivo environment. Our findings indicate that this methodology can be utilized to create plantlets for several genotypes. Nevertheless, to ensure that the majority of hybrid varieties can be cultivated in vitro, more research is required