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Wheat Information Service
Number 89: 1-6 (1999)
Research article


Effect of seed size on the tissue culture response of callus from mature embryos of wheat species

Muge T. Sayar1, Melahat A. Birsin2, Hakan Ulukan2 and Murat Ozgen2*

1Department of Molecular Biology and Genetics, Faculty of Science and Art, Bogazici University, 80815 Bebek, Istanbul, Turkey
2Department of Field Crops, Faculty of Agriculture, University of Ankara, 06110 Diskapi, Ankara, Turkey


Summary

Effect of seed size on the culture response of callus from mature embryos of different genotypes of diploid (T. monococcum L. and T. boeoticum L.), tetraploid (T. durum Desf. 'Kunduru-1149') and hexaploid (T. aestivum L. 'Bezostaja-1') wheat was investigated using recently developed endosperm-supported mature embryo culture technique. After the separation of seeds among each genotype as being large and small, they are imbibed and wounded by moving the embryos from the seed without excision completely. Following their incubation in 8mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) solution for callus induction, they are transferred onto auxin-free Murashige-Skoog (MS) medium for regeneration. Callus induction frequency, fresh weight of callus, regeneration capacity of callus and culture efficiency were found significantly higher in large seeds compare to small seeds in all genotypes. There were also significant correlation between seed weight and callus weight (r=0.86**) as well as callus weight and regenerative callus number (r=0.85**). These results suggested that efficient regenerative callus induction from endosperm supported mature embryo culture of wheat could be obtained by using large seeds. Therefore, this technique provides an alternative use of wheat mature embryos as an explant which unlike immature embryos, are available at every periods of each year in unlimited quantities.

Key words: Triticum spp., Tissue culture, Embryo culture, Callus induction, Plant regeneration.


Introduction

The achievement of biotechnological methods used for improving some agricultural properties of plants, like resistance and quality, depends on development of the most suitable callus and regeneration system for each genotype. As for other plants, callus can be formed from cereals by using different explants and thus regenerative plants can be obtained. Similarly for somatic callus culture of wheat, several explants such as immature embryo (Sears and Deckard 1982; Felfoldi and Purnhauser 1992; Bohorova et al. 1995), immature inflorescence (Ozias-Akins and Vasil 1982; Maddock et al. 1983; Sharma et al. 1995), mature embryo (Ozias-Akins and Vasil 1983; Heyser et al. 1985; Kato et al. 1991), mesocotyl (Yurkova et al. 1982), seed (Gosch-Wackerle et al. 1979), apical meristem (McHugen 1983) and young leaves (Zamora and Scott 1983) were used. Immature embryos usually are the most successfully used explants (Maddock et al. 1983; and Redway et al. 1990). However, these embryos are available only for limited periods each year thus makes their usage difficult.

*Corresponding author: mozgen@dialup.ankara.edu.tr

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