A photoautotrophic in vitro system for evaluating salt tolerance of soybean (Glycine max L.) plants

To explore the possibility of employing the photoautotrophic in vitro system for evaluating salt tolerance of soybean cultivars, a study was conducted. Three soybean cultivars, ʹLee 68ʹ, ʹZhonghuang 13ʹ, and ʹUnionʹ were cultured photoautotrophically (sugar-free medium) in vitro under seven water potentials. After three weeks, plantlet growth and leaf chlorophyll, proline, and soluble sugar contents showed that salt tolerance of these cultivars increased in the order of ʹUnionʹ, ʹZhonghuang 13ʹ, and ʹLee 68ʹ with abilities to tolerate water potentials up to -0.45, -0.91, and -1.14 MPa, respectively. The photoautotrophic in vitro salt tolerance evaluating system is apparently faster, efficient, and saves labour and cost as the performance of the cultivars can be evaluated in a few weeks compared to several months in the conventional field or greenhouse evaluations.