Factors affecting in vitro tuberization of potato

Abstract

Abstract Background Potato (Solanum tuberosum L.) is one of the most economically important annual vegetable crops. Microtubers can be produced, stored around year and directly transported to market without transferring to fresh media and without acclimatization. Thus reducing the field cycle to obtain sufficient number of seed potatoes and a high level of healthy materials. The aim of this study was to investigate effects of different combinations and concentrations of growth regulators i.e., kinetin (2.5 mg/l) and coumarin (20, 40 and 60 mg/l) alone or in addition to varied concentrations of sucrose (30, 60 and 90 g/l) on in vitro tuberization of potato (Solanum tuberosum) cv. Diamount. Results The plantlets were propagated using single-node cuttings cultured on Murashige and Skoog medium containing 0.04 mg/l kinetin and 1.0 mg/l IAA. Shoots (6–7 nodes) from the previous step were cultured into medium supplemented with a factorial combination of sucrose concentrations (30, 60 and 90 g/l), coumarin concentrations (0, 20, 40, and 60 mg/l) and two concentrations of kinetin (0 and 2.5 mg/l). Our results showed that kinetin – induced medium have slightly effect to improve tuberization in vitro. But when kinetin was combined with sucrose, this effect was better when raised sucrose concentration from 30 or 60 to 90 g/l. The highest percentage of tuberization after 8 weeks, highest number of microtuber were obtained with high concentration of sucrose (90 g/l) together with dark condition, at 18–20 °C. Also, the highest concentration of sucrose significantly increased the fresh weight of microtuber. In case of coumarin, results revealed that it has important effect on tuber initiation especially with concentrations 20 mg/l and 40 mg/l; otherwise, the initiation period was minimized after adding kinetin. So, the plantlets must be continuously incubated in coumarin –induce medium plus kinetin for 8 weeks to affect the tuberization response. Also, all the other characters of tuberization process on coumarin-inducing medium could be improved by increasing sucrose concentration to 9 g/l. Conclusions Generally, results pointed out that the treatment which consists of kinetin (2.5 mg/l) plus 90 g/l sucrose and 20 mg/l coumarin has the best characteristics of in vitro micro-tuberization.