X-RAY INDUCED IN VITRO VARIATION IN TOMATO (Lycopersicon esculentum L.)
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Date
1995
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Publisher
AAU, Anand
Abstract
The present investigation describes tissue culture studies on organogenesis via X-ray treated callus derived from cotyledonary explant of tomato (Lycopersicon escuIentum L.) vars. Junagadh Ruby and MahabaIeshwar-2 to explore the possibility of creating variability which could be used to supplement the conventional breeding programmes. Experiments were conducted using various media to induce shooting via callus. The findings revealed that maximum number of shoot bud differentiation was obtained on MS mediam supplemented with 3.0 μM IAA and 9.0 μM BA in both varieties by culturing twenty days old cotyledonary explant. In both varieties X-ray irradiation had a detrimental effect on growth of callus from lower to higher concentration in both varieties. A significant decrease in number of shoots was observed as a result of X-ray irradiation in both varieties. Maximum number of shoots as well as highest shoot length were obtained in control in both varieties. Among various X-ray treatments imposed on callus, the maximum number of shoots as well as highest shoot length were obtained in 0.1 kR in Junagadh Ruby, whereas in MahabaIeshwar-2 maximum number of shoots were obtained in 0.1 kR and highest shoot length was obtained in 0.5 kR. However minimum number of shoots as well as shortest shoot length were obtained in 12.5 kR in both varieties. Maximum number of roots were observed in MS medium supplemented with 4.0 mg-1 IBA. Significant delay in root Initiation was recorded in both varieties. X-ray irradiation significantly reduced the number of roots In both varieties. Maximum number of roots were obtained in control in both varieties. Among the plants obtained from X-ray treated callus maximum number of roots were obtained In 2.5 kR and minimum number of roots were obtained in 12.5 kR in Junagadh Ruby. In the case of Mahabateshwar-2, maximum number of shoots were obtained in 2.5 kR and minimum number of roots were obtained 0.5 kR. Longest root was obtained in 0.5 and 0.5 kR in Junagadh Ruby whereas, in Mahabaleshwar-2, longest root was obtained In 0.5 kR. Several types of morphological variants were obtained in both varieties. In the variety, Junagadh Ruby, variants varied from 23.5 - 50.0 % including dwarf habit, simple leaves, stem like leaves, Iobed leaves and elongated leaves. In the other variety, MahabaIeshwar-2, this varied form 33.3 - 45.4 % including simple leaves, potato leaf shape, chlorophyll deficiency and dwarf habit. Percentage chromosomal aberrations varied from 0.47 - 1.3 In Junagadh Ruby Including fragments, bridges and laggards whereas, 0.41 - 0.82 in MahabaIeshwar-2 including loose association of chromatids, bridges and laggards. Survival percentage of plantlets decreased with increase In X-ray dose when they were transferred into pots containing the best potting mixture, sand + soil + FYM ( 1 : 1 : 1).
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Keywords
PLANT BREEDING AND GENETICS, Agriculture, A STUDY