Wael Mtawj
Department of Horticulture, General Commission for Scientific Agricultural Research (GCSAR)
Faculty of Agriculture, Tishreen University
2017
Abstract
This research was conducted as a collaboration work between Tishreen University and Lattakia Research Center of the General Commission for Scientific Agricultural Research (GCSAR) during 2012-2017. It aims to develop a method for inducing salinity-tolerant somaclonal variations from mutant callus cultures by using Ethyl methane sulphonate (EMS) and in vitro indirect induction of vegetative shoots of potato (Solanum tuberosum) L. Cv. Marfona. The results showed that the highest callus induction 100% was on the media MS1 and MS2. The fresh weight of callus averaged was 1.93 g on MS17 after 12 weeks of planting. SHM2 was the best in terms of inducing vegetative shoots from callus by 61.67%. RM2 had the highest rooting by 100%. Five vegetative somaclonals were selected from the 2nd vegetative generation (SV2), depending on morphological and production indicators (stem length and color, no. of leaves, no. and weight of tubers/plant and average tuber weight). Ethyl methane sulphonate (EMS) was used for inducing salinity-tolerant genetics variability on Marfona cultivar by treating full-sprouted tubers at three concentrations of the mutagen (20, 30, 40) mM and at three intervals (2, 3, 4) hr. The results of 1st mutation generation (M1) showed significant differences among the studied mutating treatments. The treatment 40mM/4hr revealed low plant survival by 51%, and the 2nd mutating generation M2 showed nine changes in leaves, stem, flowers and fruits. The occurrence of these changes differed by concentration and soaking interval. The treatment 20mM/3hr gave the largest stem diameter (1.63) cm, whereas 20mM/2hr was the best and gave 1459 g and 16.8 tubers for production and no. of tubers, respectively. The results also showed that the biggest average of tuber weight and longest plant were 118.1 g and 67.22 cm, respectively for the treatment 30mM/3-4 hr. On the other hand, the treatment 40mM/3hr gave the highest number of vegetative shoots (3.90). Plants selected from the 2nd generation M2, based on morphological and production indicators, were exposed to salt concentrations by irrigating plants grown in PE bags containing a mix of crushed pumice and fluvial sand at (1:3) and water containing sodium chloride at graded concentrations (0, 50, 100, 150, 200) mM in the 3rd mutation generation. The treatment 20mM/4hr had the highest plant and number of leaves by 66.3 cm and 16.3 leaf respectively, while 30mM/4hr was the best in terms of average tuber weight (75.9) g. In addition, the results showed that the highest production (466.9) g and no. of tubers (6.31) was recorded for 40 mM/4hr under salinity stress conditions. Plants selected in the 4th mutation generation were propagated to increase the plant material. M4 plants and in vitro somaclonal variations were exposed to salt pressure for selecting the best tolerant clones in M5, depending on morphological, production and biochemical indicators (proline and chlorophyll contents). The results showed the clones 40mM/3hr/P14, 40mM/3hr/P2, 40mM/2hr/P31, 30mM/4hr/P46, 40mM/4hr/P13 and 40mM/3hr/42 were the most tolerant, giving the best values for leaf area ranging between (212.6 – 218.4) cm2, the best values for leaf content from proline (0.266-0.278) mg/g, the highest values for leaf content from chlorophylla, b (12.11-12.97) µg/ml. The results showed genetic differences between clones selected by random amplified polymorphic DNA (RAPD) and those resulted from interaction of random primers, underlying that the selected clones is genetically different from the control, Marfona.
Keywords: Potato, Marfona, Callus Induction, EMS, Mutations, Selection, Salinity.