The collection of barley mutants is suitable for use in research work (studying genetic instability and the effects of various modifying agents) and for the study process.
Barley (Hordeum vulgare L.) has been cultivated since ancient times (more than 10000 years ago) and almost everywhere, thanks to its good adaptability to a wide range of environmental conditions: high heat (the Middle East), mountainous and high altitudes (the Himalayas), regions closer to the deserts (Ethiopia, Morocco), and other areas (North America, Australia, Europe).
Barley is a monocotyledonous plant belonging to the bellflower family (Poaceae). The stems of plants in this family are composed of umbels and internodes. The leaf sheaths are open at the base of the internodes and the leaf blades are linear. Barley has specific inflorescence, spike and floret units, called spikelets. Floral stem of the spike is divided into nodes and internodes, and three spikelets develop on each internode. In two – roved, two spikelets are sterile, and only the central spikelet has a fertile floret. In six – rowed, all spikelets are fertile. Each floret comprises the lemma and palea , three stamens, the two lodicules and a single carpel. The lemma carries a bristle-like distal appendix, called the awn. The fruit of barley is the grain. The cotyledons are usually attached to the kernel, but varieties have been developed in which the kernel is loose, and the cotyledons do not grow with the husk. This benefits farmers by facilitating the grain collection process.
The genetic collection of barley mutants at VU Botanical Garden is used for research, studies and experimental material collection. The collection and storage of induced original mutants started in 1973. In 1975, the Plant Genetics Department of VU Botanical Garden was set up and the barley collection was started. The first mutants were the original quantitative, chlorophyll and morphological mutants and, in subsequent generations, revertants from some genetically unstable tweaky spike (tw) mutants. Subsequently, the collection has been enriched in other mutagenesis experiments with newly obtained mutants of tw, branched ear (be) and other types. These mutants have a common origin and long-term cultivation in the same geographical area has resulted in partially adapted plant populations which can serve not only as a subject of research but also as valuable starting material for the development of varieties.
In 1987, the collection of mutants of original origin was supplemented by lysine barley mutants downloaded from the N. Vavilov Institute (VIR, St. Petersburg, Russia) and 16 genetic lines for genetic mapping of barley. In 2001 and 2002, the collection was expanded with laxatum mutants of barley obtained from the Swedish Nordic Gene Bank. In 2002, various hooded and new laxatum mutants and other morphological mutants of barley of the ring/inflorescence type were obtained from the USDA-ARS National Small Grains Collection (Aberdeen, Idaho, USA). This collection was subsequently expanded with double and triple mutants obtained by several rounds of crosses between existing single and double mutants. The genetic collection of barley mutants at the VU Botanical Garden is the largest collection of induced plant mutants in Lithuania. Currently, the barley genetic collection consists of 22 varieties (including 15 Lithuanian varieties), 155 single mutants and genetic lines, 71 revertants, 382 double and triple mutants and breeding material.
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Barley (Hordeum vulgare L) tw mutant The first tw mutant was obtained at VU in 1974 by chemical mutagenesis from the variety 'Auksiniai II'. The spike is double, short, gradient - the blooms are weakly developed at the base of the spike and large at the tip, forming a kind of 'crown'; the internodes of the spike may be elongated and have small tears. This mutant is characterized by multiple abnormalities, such as gradient spike development, irregularly transformed into stamens and/or carpels or but also into chimeric organs, genetic instability, immune deficiency, and others.
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Barley (Hordeum vulgare L.) Lemma hooded (Lh) mutant The mutant has a unique spike appearance. The spike is hexamerous, the ectopic floral structures develop on the awns and their structure varies from slight thickening on the awn to a fully developed ectopic ring and a normal awn. The spike-scales of this mutant have evolved into inflorescences which have normal awns, ectopic rings, or the beginnings of such. |
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Barley (Hordeum vulgare L.) mutant tw2Br38 Resulting from a cross between tw2 and Brittle rachis. The plant has no waxy covering (eceriferum). The spikes are two – rowed, the extra flowers ectopically develop in place of awns. The anthocyanin color of the grains becomes apparent after the plant has emerged but before the spikes are fully mature.
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Barley (Hordeum vulgare L.) mutant tw2Br6 Resulting from a cross between tw2 and Brittle rachis. The plant is short, the spike is small (compact), awns are long, fan-shaped, lateral rows of spikelets small. As the plant matures, it is possible to observe changes in the color of the grain until the spikes are fully mature (black). |
