GrainGenes
A Database for Triticeae and Avena
M. Ilhan Çagirganı , Metin B. Yildirim², M. Emin Tugay³
²Department of Field Crops, Faculty of Agriculture, Ege University, Izmir, Turkey
³Dept. of Field Crops, Faculty of Agriculture, Cumhuriyet University,Tokat, Turkey
Gigantum (giant) mutants have been reported in pea, tomato and barley. In these cases several or all plant parts were enlarged (Kawai 1977) despite the fact that the reverse has been the most common experience in mutation breeding programs, resulting useless material for direct propagation for variety release.
In our mutation breeding program a gigantum mutant, M-Q-54, was selected in the M2 generation of a two-row spring habit "Quantum" barley of which the seeds were irradiated with 150 Gy of gamma-rays from a ^60^Co source at the International Atomic Energy Agency laborotories, Seibersdorf, Austria. The irradiated seeds were sown to grow M1 generation in 1985 in Tokat province and harvested as single spikes from each plants in July 1986. The M2 generation was arranged in the form of M1 spike-to-row progenies, consisting of one row of 150 cm length, 30 cm apart and 16 seeds sown. A total of 1459 M2 family were grown in 1986-1987 season as a winter nursery to screen cold tolerant plants.
Some well-developing plants having erect habit took our attention in a family. They were selected and further characterized by taller plant height, thicker stem diameter, bigger kernels, more tillers, higher single plant grain yield than the parent variety 'Quantum'. These attributes were confirmed in the M3 and M4 generations grown in two replicated progeny rows. It was also revealed that the mutant has had better cold tolerance according to 1-5 scale and higher biological yield than its spring parent variety. However harvest index did not changed or slightly decreased (see Table). This mutant has also shown wider adaptability than its parent variety especially in areas where both soil fertility and rainfall are limiting factor. Because of its longer basal internode length in yielding environments, consequently, it is sussceptible to lodging. Nevertheles, we have found very useful and practical testing mutants in different environments.
In the mutant population, M-Q-54 was the only morphologically deviating variant for which we could select. On the M2 family basis, the mutation frequency was 6.9 X 10^(-4).
We consider that M-Q-54 will be useful for both directly variety release and for developing strains and varieties that may be performed well in more stressful environments.
Table. Phenotypic characteristics of the mutant 'M-Q-54' as related to the parent variety 'Quantum' over the generations M2-M6 grown in contrasting environments.Acknowledgements______________________________________________________ Characteristics Phenotypic value ______________________________________________________ Lodging tolerance Less than in fertile soils Basal internode length More than Plant height More than Spike length Less than Spike density More than Stem thickness More than Cold tolerance More than Drought tolerance More than General adaptability More than Number of tillers More than Number of grains per spike Less than Thousand grains weight More than Grain yield More than Biological yield More than Harvest index Equal to or less than ______________________________________________________
We are kindly thankful to Dr. Helmut Brunner of International Atomic Energy Agency, Seibersdorf, Austria, for the seed irradiation of the material with gamma rays. The contributions of Mustafa Polat and Emin Ergan in growing plant materials are gratefully recognized.
References:
Kawai, T. 1977. Plant Type and Growth Habit. In: Manual on Mutation Breeding. Second Edi. Tech. Rep. Ser. No:119 . International Atomic Energy Agency, Vienna, pp.173-174.