These wild varieties were then cultivated, creating landraces, which spread across Europe, Africa, and Asia right image. All barley cultivars worldwide derive from these landraces. Each dot on the maps represents the collection site of an individual accession in the Global Inventory of Barley Genetic Resources.
Ana Poets, Zhou Fang, and Peter Morrell at the University of Minnesota and Michael Clegg of the University of California, Irvine, examined a larger collection of barley landraces of them to see if there is any clustering within the landraces.
And they found a lot of it, with six major clusters. More surprisingly, in two-dimensional space those clusters can be overlain on a map of where the landraces are found. These studies are interesting because they indicate that landraces tend to stick to certain geographic regions.
Russell, Mascher, and colleagues delved deeper into their Fertile Crescent findings and analyzed a data set including 91 wild and landraces. The scientists narrowed the geographic range of their analysis because they were primarily interested in the genetics of five special accessions.
They separated the landrace individuals from the wild accessions, and each of the wild accessions was then assigned to one of five ancestral populations.
The wild strains fall into two recognizable clusters, suggesting that they come from two well-defined ancestral populations.
The geographic break between the two clusters appears to be between a group of accessions mostly from Israel, Cyprus, Lebanon, and Syria, and those from Turkey and Iran.
Once they had obtained the detailed picture of wild strains, the researchers analyzed the landraces. They found that there are at least three ancestral patterns for landrace barley from this region.
The five special accessions mentioned earlier are included in this analysis; and they are as special as accessions get, because they consist of 6,year-old barley kernels, found in Israel, that are believed to represent cultivars that humans used all that time ago. And they appear to be very similar to modern landraces. More specifically, these cultivars show close affinity to current landraces from Israel and Egypt. This result is spot on with the idea that the domestication of barley was initiated in the Upper Jordan Valley.
Close examination of the ancestral components of these five samples suggests that the Israeli landraces grown today have not changed much in 6, years, despite some occasional mating with wild strains. Genome-level information is instructive not only about the ancestry of barley, but also about the genes that might have been involved in its domestication. We have already discussed the major outward difference that distinguishes wild accessions from landraces—the brittle spike.
But other traits were certainly also selected for by barley breeders over the past 10, years. Indeed, Russell, Mascher, and colleagues used their data set to identify the kinds of genes that have been, and continue to be, under selection in landraces.
Among the traits they showed to be under breeding selection over the past several millennia are days to flowering, and height as response to temperature and dryness. Both traits are important in the adaptation of cultivated barleys to their domestic circumstances.
But as the scientists point out, there are doubtless many factors still to be uncovered. More genomics work will help us discover what they are. What about the brittle spike trait that we have seen was perhaps the most important genetic change during domestication? It turns out that the trait is under quite simple genetic control. Two genes are involved, Btr1 and Btr2 , whose protein products interact with each other.
When these two gene products interact properly, the central stem, or rachis, is brittle; but if there is an abnormal interaction as the result of gene mutation, the rachis stays strong, and no shattering occurs. Other domestic grains, such as rice and wheat, also have strong rachises, raising the question of whether breeders of rice, wheat, and barley selected for this trait in these grains via the same genetic pathways.
Clearly, there is more than one way to achieve the same rachis qualities. This theme is a common one in evolutionary biology, so it is hardly surprising that plant breeders have also stumbled onto the same principle using artificial selection.
In the first sentence of his review of barley biology, Robin G. Allaby clarifies our interpretation of the genomic data by pointing out that every single landrace of barley so far examined has genomic remnants of the four or five ancestral wild accessions, and he raises a key question—is barley the exception among domesticated forms, or is it the rule?
The answer is that barley might well illustrate the rule. Domestication—which in the case of barley seems to have taken place over the general region of the Fertile Crescent—was evidently not a simple process. With the rise of genomic technology, a very different approach to barley breeding has now become possible, using cheaper and faster techniques.
In the past, the breeding of landraces of barley possessing the most desirable traits for agriculture was a trial-and-error affair.
Six thousand years ago, barley farmers knew nothing of formal genetics, but they were smart and clearly knew enough about their plants to achieve the results they wanted. Breeders continue to grapple with the same two major kinds of traits: yield and quality. Yield traits include features such as numbers of seeds set, capacity to breed multiple times a year, or the brittle spike character that, if mutated, allows for more efficient harvesting.
Quality traits are those that effect the protein content, oil content, or any other phenotype concerned with the nutritive content of the plant. During the 20th century, barley breeders were still using their knowledge of classical genetics to facilitate breeding in a tedious and labor-intensive process. With the rise of genomic technology, and the ease with which it can be applied to large numbers of lines and landraces, a very different approach to barley and other grain breeding has now become possible, using cheaper and faster techniques.
Genome-based plant breeding uses a concept called genomic prediction that relies on the predictive abilities of traits. It requires genome-level sequencing of large numbers of landraces, as well as abundant data on the traits that might be targeted such as seed size, protein content, and protein yield.
Prior to the use of this approach, barley breeding experiments were massive and costly. Now, using genomic prediction, barley breeders can get a more precise, quicker, and cheaper idea of how easy it will be to breed for certain traits. Several such studies have already been directed at the assessment of quality traits that are important in brewing. Malthe Schmidt of the German plant-breeding company KWS SAAT and his colleagues analyzed the predictive abilities of 12 malting characteristics of spring and winter barleys.
Is it simply tradition, or is the make-up of barley essential for creating anything that can really be defined as "beer"? I'm aware there are sorghum beers, but that's only for the unfortunate folks with gluten allergies, so I'm not counting them.
They've all been tried over and over again yet practically everywhere that barley is available it's the grain of choice. Many reasons,a main one would be that it malts very easily and well. Wheat is incredibly difficult to malt properly there are physical reasons for this Barley has versatility and is cheap and easy to grow.
And it tastes pretty good too. Barley is a basic cereal grain not particularly good for milling into flour and making bread or bakery goods. But it is great for beer. There are three major types of barley. These are differentiated by the number of seeds at the top of the stalk. Barley seeds grow in two, four and six rows along the central stem.
Brewers in the US traditionally prefer six-row barley because it is more economical to grow and has a higher concentration of enzymes needed to convert the starch in the grain into sugar and other fermentables. JimKal , Roguer , BrettHead and 4 others like this. While beer can be made from other grains, barley provides some benefits for beer making.
Its husk offers protection against the damage caused by handling the grain, particularly the regular turning to separate the grains during germination. A brewer can compensate via other means e. By brewing with a mix of malted barley and malted wheat the brewer does not need to worry about a stuck sparge. At this point, it is called "green malt. The trick is that you don't want the barley to sprout too much.
After about five days of soaking, the grain will want to take root and grow a new plant. Maltsters—the skilled people in charge of the malting process—want to stop the germination process before this happens. This is done with heat. Maltsters kiln, or dry, the green malt by slowly raising the temperature to more than F. The final temperatures vary depending on what kind of malt they want in the end. No matter the temperature, the result is the same: the growth of the sprouts is stopped.
What is left is a dried barley grain full of sugar, starch, and a particular kind of enzyme called diastase. It is during this stage where the final beer begins to take its shape.
The level of heat that the green malt is subjected to will play a big role in the final style of beer that is produced. It has much to do with determining the color of beer:. To further complicate matters, the finished malt may be roasted after kilning. This is done at high temperatures in a roaster. The level of roasting will factor into the darkness of the beer as well as the amount of carbonation it has. During the fermentation stage, a particular strain of yeast is introduced to further define the beer.
For instance, pale ales and lagers require almost the same level of kilning.
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