Studies On Induced Mutation Of Strawberry In Vitro And Selection For Salt-tolerance Variant

In the present experiment, the screening techniques for salt tolerance and mutants of strawberry leaf and anther callus in vitro were studied, and primary screening system for salt tolerance evaluation was established. It was studied the sensitivity to mutagen of different strawberry cultivars and different tissues in vitro. Also, the difference in salt tolerance of variants was compared.1. Induction treatments. All of Ethyl methanesulfonate(EMS), ⁶⁰Co Gamma rays and interactive treatment can induce the strawberry tissues in vitro, and using EMS or ⁶⁰Co-γ rays separately had no distinctive difference ,but the interactive treatment injured strawberry in vitro seriously, the regeneration decreased about 10% to 15% than that of treating with single mutagen.When treatment leaves in vitro with EMS only, two different ways were applied as bellow: â‘  Treatment with mutagen solution. (2) Treatment with mutagen added to medium. And the first method was better. There were different optimal combinations of treatment in different mutagens, treatment ways and in allusion to various tissues in vitro, both considering of the survival and regeneration rates, the best combination of treatment were as follows, leaf in vitro: treatment with EMS solution: (0.2%-0.4%) + (1.0h-2.0h);treatment with ⁶⁰Co-γ rays: 3-5KR;interactive treatment: 3KR+(EMS)lh+0.2%,3KR+(EMS)2h+0.l%;Anther callus: treatment with EMS solution: 1.5h+0.1%, 1h+0.2%.2. Sensitivity to mutagen. When treatment on the leaves in vitro of strawberry cultivars of All Star and Xinminxing by any mutagens, the result showed that the survival and regeneration rates have no difference .It indicated that the two strawberry cultivars were similar in genetypes and had same sensitivity to any mutagen. The anther callus of All Star was more sensitive to EMS than that of leaf in vitro, and it might generate salt-tolerant variation easily.3. Physiological Change for mutant plants and comparison of salt tolerance of induced mutation. After primary selection from critical content of NaCl, the induced mutants could resist salt stress by increasing SODase,PODase activities, content of free proline , and decreasing content of MDA, value of Na+/ K+. The salt tolerance of all the induced mutation was higher than that of control. The salt tolerance of variants with interactive treatment from leaf in vitro and the anther callus regeneration plants were the highest.