| EMS-induced sphaerococcum mutation in Triticale
Sevdalin GEORGIEV Institute of Introduction and Plant Resources - Sadovo 4122, Plovdivsko, Bulgaria Using monosome analysis (SEARS 1947) estabilished the localisation of the gene which controls the symptoms characteristic of T. sphaerococcum Perc., as a hemizygous ineffective/ zero allele/in 3D/XVI chromosome. Later by the telocentric method (PRABHEKARA RAO 1977) affirmed the localization of this gene in the short arm of 3D chromosome. As a result of the application of radiation and chemical mutagens, mutants of the sphaerococcum type were obtained in 2x, wheats (GEORGIEV & NICOLOFF 1975, GEORGIEV 1979), 4x wheats (BOZZINI 1965) and 6x species of the Triticum genus (SWAMINATHAN et al. 1963), GEORGIEV 1976). Induced sphaerococcum type mutation in Triticale has not been described until now, and the present work is preliminary communication and description of a sphaerococcum type of mutation in Triticale (2n=6x=42) after treatment with EMS. Materials and Methods Seeds of the hexaploid Triticale cultivars MT 47 - Armadilo, calibrated in advance, were treated with 0.5% aerated water solution of EMS at pH=4.5 (Sorensen buffer) for 3 and 5 hours. Five hundred seeds (0.1 ml/seed) were treated from each variant at 24o + or - 0.5C. After rinsing with running water for 30 to 40 minutes the seeds were sown parallel with controls - seeds soaked in distilled water in advance. For M2 the sowing was carried out in progenies. Results and Discussion Among the plants in the M1 generation in the variants of Armadilo treated with 0.5% EMS at pH=4.5 for 3 hour and 0.5% EMS at pH=4.5 for 5 hours, 3 chimeral plants with characteristics typical of the phenotype of the hexaploid species T. sphaerococaum Perc., 2n=6x=42, have been observed. The mutant sector in the M1 chimeral plants affected only part of the spike (Fig. 1). As can be seen from Fig. 1B, the length of the glumes of the mutant spike is shorter as compared to the controls, and the length of the mutant stem is 20 cm, shorter than the remaining ones with standard phenotype. From these plants we obtained a total 18 grains originated both from the mutants and from the standard earlets of the chimeral spike. The seeds obtained are shortened, with a hemispherical shape and they had the typical form of the glumes. Among 100 M2 progenies of the tested total 2075 M2 plants of MT 47 treated with 0.5% EMS at 4.5 pH for 3h, five plants were observed with features typical of the hexaploid type T. sphaerooocum Perc. The mutant plants were shorter by 30 cm than the plants with standard phenotype and possessed an errect habit with an upright disposition and shortened and bent on the top leaves. As is seen from Fig. 2B and Fig. 3, the mutant plants possessed shortened compact ears, shortened and hemispherical ear glumes and seeds, with completely reduced length of the awns. |
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