ASSESSMENT OF NOVEL EMS-INDUCED GENETIC VARIABILITY IN RAPESEED (BRASSICA NAPUS L.) AND SELECTION OF PROMISING MUTANTS

Induced mutation may be an effective alternative to get a novel genetic variability that might not be found in natural germplasm. Seeds of Brassica napus L. (variety 'INRA-CZH2') were treated with Ethyl Methane Sulphonate (EMS), in 1, 1.2, 1.4 and 1.6% doses for 6, 7 and 14 hours, and were planted to obtain the M-1 plants and then the M-2 plants. The objective of this study was to evaluate the novel induced variability observed for some important quantitative traits and to select mutants with modified and interesting characteristics. Data were recorded on 10 random plants taken from M-2 populations derived from each treatment (dose by duration), along with control plants (wild type), and were evaluated in two contrasted environments. A considerable variability was observed, and EMS treatment had a significant effect on all the traits studied. Compared to control plants, mutants coming from seeds treated with low EMS doses for moderate time, namely 1% EMS (7 hours), flowered and matured earlier and had higher number of pods per plant in both environments. In addition, they were generally more adapted than the check and the other mutants to stressful environments associated with low rainfall, high temperature and late planting at Allal Tazi location. This would explain phenotypic stability and adaptability of these mutants to the environments studied. Besides, late planting at Allal Tazi location was harmful for all the plant materials studied (check and mutants) having exhibited lower performance compared to early planting at Douyet location. Interestingly, this is the first time that a rapeseed mutant combining such desirable characteristics is obtained. This promising mutant exhibiting its stability throughout M-1 and M-2 generations in both the environments will be valuable and useful for fast development of adapted and agronomically superior rapeseed cultivar.