Title : Physical mutagenesis application in selection of Sesamum indicum L.
Relevance of carrying out researches on selection of tropical culture – (Sesamum indicum L.) is caused by warming of climate in general and in Pridnestrovie, in particular, and also wide use of seeds in the food industry and sesame absence in the variety register allowed touse in Pridnestrovie. Researches were conducted in Tiraspol, located on 46th northern latitude. Therefore, it was necessary to receive short vegetative period forms not more than 145 days first of all.
Physical mutagenesis was used as a selection method because of absence of sesame various initial material.
The collection sample of the Republican botanical garden (Tiraspol) of sesame of unknown origin relating to Asian group (ssp bicarpellatum Hilt, var. albidum) has been served as an initial material for receiving mutant posterity. Seeds coloring whit with a gray shade, branchiness of stalks from 3 to 6 - 7, in a leaf bosom 1 box.
Mutant material was received in 2012 by seeds irradiation of 60Co radioactive isotope on the «Researcher» gamma-ray irradiation facility (fig. 1) located in Pridnestrovian research institute of agriculture (Tiraspol), using up to 240 Gray doses.
Two varieties of sesame Lebed and Mulatka suitable for cultivation in Pridnestrovie were received as a result of research. The sesame variety Lebed, was created by a physical mutagenesis method with the subsequent selection of the best line. Plants have 130-140 days of the vegetative period duration, 165-175 cm height, 7-8 escapes of the first order, first branch height laying at 10-13 cm, flowers are trimmed, light pink (fig. 2). Productive part of the main escape length is 100-115 cm on which there are from 50 to 76 densely located boxes (fig. 3). 250-400 of boxes are formed on a plant in total, when maturing crack poorly. Boxes length is about of 24-25 mm. Seeds mass from one plant – 25-55 g, (maximum from some plants up to 75 g). Weight of 1000 of seeds – 2,7 – 2,9 g. Seeds are white with a cream shade and have an extended form (fig. 4). The productivity is about 20-22 c/hectare without irrigation.
The sesame variety Mulatka plants height is about 150-160 cm with 5-10 escapes of the first order. First branch height laying at 10-15 cm. Flowers are trimmed, light-violet with small dark-violet spots on an internal surface of four side petals and larger – on a lower lip of a flower (Fig. 5). Productive part of the main escape length is 100-115 cm on which there are from 48 to 60 boxes (Fig. 6). 200-250 of boxes are formed on a plant in total, when maturing crack poorly. Boxes length is about of 25-26 mm (Fig. 7). Seeds mass from one plant – 18-30 g, on some plants is formed up to 45 g. Weight of 1000 of seeds – 2,6-2,8 g. Seeds are light brown color with an extended form (Fig. 8). The productivity is about 17-20 c/hectare without irrigation.
Take Away Notes:
• For sesame irradiation doses at which it is possible to receive a high variety of mutant forms with useful signs are defined.
• An initial material for selection is characterized in following plants signs: forms with a length of vegetative period up to 145 days, upright arrangement of escapes, dense arrangement of boxes, plants with an acinaciform boxes with well-developed false partitions which are steady against of seeds fall, different color of seeds, with sterile forms.
• The physical mutagenesis method allows to receive desirable practical results very quickly and especially effective at a limit of initial material variety, for cultures promotion to a nonconventional regions of cultivation for expansion of species areas.Received mutants are of practical interest to expansion of sesame genetic variety in the different directions of selection process. Also, received initial selection material are of interest to physiologists for the purpose of assessment on: drought and salt resistance, to soil reaction and for ecological geneticists for determination of genotypes potential in different climatic zones. In general, received initial selection material will allow to accelerate selection process.