# Application of Biotechnology for Sunflower Inbred Line Development: Immature Embryo Rescue
New methodologies of sunflower breeding introduce a new system by using inbred line B-PET1-rf1 Rf1, reducing the inbred lines' development down to two inbred lines [21; 22]. The use of inbred lines provides several advantages, including genetic stability and improving F1 seed production [8]. A major challenge in modern sunflower breeding involves overcoming difficulties related to the development of inbred lines, which require a minimum of 6-8 generations before being introduced into breeding programs. One solution to address these challenges is the application of biotechnology in sunflower improvement through the optimization of more efficient technologies for generating new sunflower genotypes [23]. Biotechnology has significantly influenced sunflower breeding by enabling advanced genetic improvement techniques, including the use of molecular markers that allow for the rapid identification of target genes [24; 25], genomic selection that estimates genetic value based on whole-genome analysis [26], and the introduction of in vitro cultures in breeding programs [27; 28; 29]. The use of biotechnological techniques for plant regeneration from immature embryos has a significant benefit in sunflower breeding, enabling the recovery of viable genotypes from interspecific crosses to enhance genetics [28; 29]. Immuture embryo rescue is one of the methods used for obtaining inbred lines in a short period, offering the advantage of seed harvesting at physiological maturity and the continuation of the line development process. The applicability of immature embryo rescue also extends to interspecific crosses, being utilized for obtaining tolerance to abiotic and biotic factors [30]. Immature embryo rescue technology has facilitated genetic diversity by enabling the recovery of viable embryos from interspecific crosses involving _Helianthus annuus_ and _Helianthus decapetalus_, _H. originals, H. angustifolius, H. resinosus, H. nuttallii, H. deblis, H. argophyllus_, and many others [31]. Pre-zygotic barriers primarily involve reproductive incompatibilities that prevent fertilization, whereas post-zygotic barriers can restrict or impair embryo development. Immature embryo rescue procedures help the sunflower breeding programs to not only enhance the success rate of hybridization, but also to enable the generation of haploids and doubled haploids [32]. According to the present studies, 15-day-old immature embryos enabled the development of drought-tolerant genotypes de rived from the wild species _H. argophyllus_ by supplementing MS media with hormones [33]. Other reports of using immature embryo rescue methodologies reveal the successful rescue of immature embryos up to the flowering stage, managing the development of imidazoline sunflowers [34]. Additionally, in vitro cultures have been applied in various fields, such as plant regeneration through organogenesis and embryogenesis in culture media [35], the induction of genetic variability through mutation induction [36; 37; 38], and the production of haploids through anther and pollen culture to obtain haploid lines for breeding programs [39; 40]. In vitro technology relies on sterile conditions and nutrient-rich media to enhance plant survival rates. By placing plants in culture media, nutrients--including macroelements, microelements, and vitamins--necessary for growth and development are supplied. [PERSON] (MS) established a widely used culture medium containing macroelements, microelements, vitamins, and growth regulators including auxins, cytokins, and gibberells [41], and agar as a gelling agent in the optimal pH for plant growth ranges between 5.0 and 6.0 [42; 43]. Among the most widely used and important methods in sunflower breeding are in vitro cultures. Providing an optimal balance of hormones can significantly improve the embryo rescue rate. Additionally, accurately identifying the stage of the embryos is essential to maximize the efficiency of this technique, as the reduced germination of immature embryos is often caused by dormancy or an insufficiently developed embryo.