Optimization of In Vitro Ovule Culture System in Upland Cotton

In vitro ovule culture serves as an experimental platform for exploring the growth and development processes of cotton fibers. However, over the decades, research on the in vitro ovule culture of upland cotton has remained underdeveloped. In this study, ovules collected 2 days post-anthesis (2 DPA) from the upland cotton genetic standard line TM-1 were used to investigate the effects of carbon sources (glucose, fructose, sucrose), kinetin (KT), and glutamine (Gln) on ovule growth and observed fiber development in vitro. The results showed that the ovules grew more favorably on a medium supplemented with 0.05 M glucose, 0.02 M fructose, and their degradation products as carbon sources. Regarding the role of KT, it has a slight inhibitory effect on the development of cotton fiber in vitro at a lower concentration (0.1 mg/L). However, as the concentration increased (0.5 mg/L), its effect shifted to promotion. Additionally, Gln demonstrated the ability to enhance the characteristics of fiber fluffiness. In this study, the optimized formula for the in vitro ovule culture of upland cotton was established. This method provides an improved technical system for the in vitro ovule culture of upland cotton, holding great potential for fiber function genomics and seed bioengineering in cotton.