Induced mutation variability in Linum grandiflorum Desp

Linum grandiflorum is a popular crop on the European market of ornamental plants. It is commonly used as a flowerbed crop. L. grandiflorum is known for its limited genetic variability. Up to now its colour spectrum remains poor and mutations of flower shape, which are not of small importance for any ornamental crop advancement on the consumer market, are unknown. It was supposed in this connection, that the method of chemical mutagenesis had to broaden the mutation spectrum and to increase the frequency of useful mutations in comparison with natural variability. Seeds of annual wild species of L. grandiflorum with a large ruby corolla and a dark red spot at the centre of the flower (var. rubrum) were treated with 0.01, 0.05, 0.1 and 0.5% of ethyl methanesulphonate (EMS) for 18 hours. After treatment the seeds were washed to remove the mutagen. Seeds of every M1 plant were sown separately in individual plant-to- progeny rows. In the M2 generation the majority of visually selected mutants were selfed and advanced from M2 to M3, where every mutant line was raised along with the parental genotype. The results of screening M2 segregating material indicated that L. grandiflorum was characterized by a high frequency of morphological mutations. Six types of mutants, namely chlorophyll deficiency, leaf waxy bloom, corolla colour, flower shape and size, and plant habit were selected from the M2 generation). EMS concentrations of 0.05 and 0.1% were the most optimal to induce the greatest number of mutants, taking into account the high survival rate of plants in M1. Half of the mutants were found with modified chlorophyll content and one-third had a new habit. Under 0.05 and 0.1% EMS treatments only super-dwarf plants and plants with the modified corolla colour were found. The spectrum of chlorophyll mutants isolated in the present study comprised of albina, viridis and xantha mutations. The variant super-dwarf possessed a phenotype of small (several centimetres in height only), half-spheric bush. Chlorophyll-deficient mutations were often observed among this variant. All the selected 'sd' plants were not viable. Compared with the wild type plants, the dwarf mutants ('d') had shorter internodes, leaves were also shortened and thickened petals were of darker colour. Mutations of corolla colour and corolla shape were of the greatest interest with a view to obtain new ornamental varieties. The unique variant 'apr' possessed a phenotype with apricot petal colour and a mahogany spot at the center of the flower. The mutation of corolla shape was represented by the star-shaped flower ('star' mutant) [1]. Both these mutants had a high viability. The mutant with an apricot coloured corolla successfully passed variety testing and under the name of 'Aurora' was included in the State Register of Plant Varieties in the Ukraine for 2002. Another mutant with a star-shaped flower is now under State Variety Testing.