Effectiveness of gamma ray irradiation and ethyl methane sulphonate on <i>in vitro</i> mutagenesis of strawberry

Abstract

The experiment was conducted to study the effect of gamma-ray irradiation on the high concentration thidiazuron (TDZ) produced buds. In vitro buds were irradiated with different gamma-ray doses. Akihime cultivar (‘Akihime’) was irradiated with the doses of 0, 30, 80, 130, 180, and 230 Gy while ‘DNKW001 accession’ (‘DNKW001’) was exposed to the doses of 0, 30, 80, 130, 180, 230, 280, 300 and 325 Gy and similar doses of gamma rays + EMS 7uM (GRE) treatments. Survival rate and plantlet performance of DNKW001 in gamma ray + EMS 7uM treatment declined profoundly with increasing doses and LD₅₀ was lower (104 Gy) than LD₅₀ in gamma ray irradiation (177 Gy) alone. Variants of plantlets were detected in pre (white streaked leaf and bigger petiole with distorted leaf) and post acclimations (dwarf, dwarf-necrosis, variegated, dark-rigid-thick leaf, rumpled leaf, heart shape-bright red fruit). Hexadecaploid of Akihime and pentadecaploid, 13x + 4 chormosome, and diplodecaploid of DNKW001 were discovered sturdy plants with thicker leaf and bigger pollen than octoploid plant, while the monosomic octoploid performed a dwarf plant. Outstanding variants based on fruit weight, total soluble solid content and color in plot of Principle Component Analysis (PCA) were selected and proved as mutants in DNA level. Gamma ray irradiation + EMS was more effective to generate more type and magnitude of variants. Irradiation dose less than 130 Gy was ample for generating variant plants of strawberry.

Keywords: Survival rate, LD₅₀, dwarf, thick leaf, monosomic octoploid, hexadecaploid, diplodecaploid, PCA

African Journal of Biotechnology Vol. 12(30), pp. 4803-4812