MORPHOLOGICAL CONTROL AND MENSURATION OF POTATO PLANTLETS FROM TISSUE-CULTURES FOR AUTOMATED MICROPROPAGATION

Automation in plant micropropagation can be greatly simplified if the propagated plantlets have some morphological properties that facilitat e automatic chopping and subsequent inspection and classification of t he pre-cut plantlet segments by machine vision as viable propagules. W e were able to control the morphogenic pattern of in vitro-propagated potato plantlets by adding various concentrations of ancymidol to the nutrient solution. It was found that plantlets cultured in 0.25 mg l(- 1) ancymidol best fit the requirements for automated mass micropropaga tion; the mean internode length was sufficiently large (9-10 mm), the color contrast between leaves and stems was significantly enhanced, th e stem was thicker than in the control treatment and the number of axi llary buds per plantlet was maximized. Microtuber formation on segment s isolated from plants cultured in 0.25 and 0.5 mg l(-1) ancymidol med ia was enhanced shortly after transfer to tuber induction medium in vi tro. On shoot segments from control plants, microtuber formation start ed after 24-28 days. Machine vision was used to evaluate the morpholog ical and color changes in cultured potato plants. Geometrical and colo r features such as the number of buds, internode length and color cont rast between leaf and stem were precisely measured and automatically l ogged. Features were measured that till now could only be observed qua litatively.