The Soviet Union was obsessed with one grain in particular: wheat. And on quite a number of occasions Lysenko and his researchers were criticized for not producing a variety that could grow well in the short growing season. And then there was the controversy over winter vs. spring wheat (with the wrong approach apparently originating from the US actually). At any rate, eventually the Soviet Union over-planted and over-extended the range of winter wheat for the climates, and after a series of harsh winters, experienced disastrous crop failures requiring them to import huge amounts of wheat.
But wheat is a complex plant that doesn't yield easily to Mendelian genetics. It's a haploid hybrid of three diploid grasses. In the terms of the more advanced genetics, it is genomically unstable. Mendelians mocked Lysenko when he reported grains of rye appearing in ears of wheat grain. But Lysenko was right about this; it's quite possible for wheat to introgress with diploids like rye as well as tetraploid species. There is even a hybrid of wheat and rye now produced commercially (this was done without advanced GM techniques). The Soviet Union had long been interested in this, but as Lysenko himself reported, the results they got were sterile. They also tried crossing wheat with other native grasses to make it more hardy and productive in the harsher climates of the Soviet Union. Success at getting a wheat-rye cross that could reproduce came much later. The major advances in improving wheat production came in the 19th century more or less indifferent to Mendelian genetics. Mendelian genetics and inbreeding techniques in the first half of the 20th century did yield some gains into disease resistance. This was combined with the traditional plant breeding methods (of which Michurin and Lysenko approved) in Mexico to yield the so-called Green Revolution's hybrids (the key was old-fashioned cross-breeding with E. Asian dwarf wheat). One irony would be that such a big step forward was based on such an old technique. The other irony might be that it couldn't be done today because some company or government might have a patent on the Japanese wheat's genes! http://mbe.oxfordjournals.org/cgi/content/abstract/msi196v1 Introgressive hybridization has played a crucial role in the evolution of many plant species, especially polyploids. The duplicated genetic material and wide geographical distribution facilitates hybridization and introgression among polyploid species having either homologous or homoeologous genomes. Such introgression may lead to the production of recombinant genomes that are more difficult to form at the diploid level. Crop genes that have introgressed into wild relatives can increase the capability of the wild relatives to adapt to agricultural environments and compete with crops, or to compete with other wild species. Although the transfer of genes from crops into their con-specific immediate wild progenitors has been reported, little is known about spontaneous gene movement from crops to more distantly related species. We describe recent spontaneous DNA introgression from domesticated polyploid wheat into distantly related, wild tetraploid Aegilops peregrina (syn. Ae. variabilis), and the stabilization of this sequence in wild populations despite not having homologous chromosomes. Our results show that DNA can spontaneously introgress between homoeologous genomes of species of the tribe Triticeae and, in the case of crop-wild relatives, possibly enrich the wild population. These results also emphasize the need for fail-safe mechanisms in transgenic crops to prevent gene flow where there may be ecological risks. Keywords: Introgression; Wheat; Triticum aestivum; Aegilops peregrina; Polyploidy; Transgenic crops. http://www.desicca.de/plant_breeding/Rye_introgression/body_rye_introgression.html Current list of wheats with rye introgression of homoeologous groups 1, 4 and 5 After the first reports on spontaneous wheat-rye chromosome substitutions 5R(5A) by Katterman (1937), O'Mara (1946) and Riley and Chapman (1958), during the past three decades particularly, 1R(1B) substitutions and 1RS.1BL translocations were described in more than 200 cultivars of wheat from all over the world (Blüthner and Mettin 1973; Mettin et al. 1973; Zeller 1972; Zeller 1973; Zeller and Fischbeck 1971). Their most important phenotypic deviation from common wheat cultivars is the so-called wheat-rye resistance, i. e. the presence of wide-range resistance to races of powdery mildew and rusts (Bartos and Bares 1971; Zeller 1973), which is linked with decreased breadmaking quality (Zeller et al. 1982), good ecological adaptability and yield performance (Rajaram et al. 1983; Schlegel and Meinel 1994). The origin of the alien chromosome was intensively discussed by genetic and historical reasons. It turned out that basically four sources exist - two in Germany (it might be one source, see Schlegel and Korzun 1997), one in the USA and one in Japan. The variety 'Salmon' (1RS.1BL) is a representative of the latter (Tsunewaki 1964) and the variety 'Amigo' (1RS.1AL) is a representative of the penultimate group (Beronsky et al. 1991; The et al. 1992), while almost all remaining cultivars can be traced back to one or to the other German origin (Zeller 1973; Blüthner and Mettin 1977). There was no doubt so far that the Japanese and the American derivatives differ from one another and from the German sources. Although on two places of Germany - Salzmuende near Halle/S (breeder: Riebesel) and Weihenstephan near Munich (breeder: Kattermann) - wheat-rye crosses were already carried out since the twenties and thirties and independent pedigrees could be fragmentally reconstructed by the few reports left (Blüthner 1992), some authors presumed only one German source (Lein 1975; Moonen and Zeven 1984; Schlegel and Korzun 1997). For breeding programmes additional recombination within the translocated 1RS arm of rye and between the different wheat genetic backgrounds is wished (Müller et al. 1991a; Lutz et al. 1992). http://en.wikipedia.org/wiki/Physiological_and_molecular_wheat_breeding#3..09Mendelian_genetics_and_the_green_revolution 3. Mendelian genetics and the green revolution Mendel's experiment stimulated research by many plant scientists dedicated in improving crop production (plant breeders) through plant breeding. The most famous contribution of Mendelian genetics was hybridization. There was remarkable improvement in three economically important crops that made the food deficit world into a food surplus world. This is called the green revolution. The first, development of hybrid maize, the second development of high yielding and input responsive “semi-dwarf wheat” (CIMMYT breeder N.E. Borlaug received Nobel prize for peace in 1970), the third is high yielding “short sutured rice” cultivars. Similarly the remarkable improvements were done in other crops like sorghum and alfalfa. http://www.statemaster.com/encyclopedia/Wheat Plant Breeding In traditional agricultural systems wheat is often grown as landraces, informal farmer-maintained populations that often maintain high levels of morophological diversity. Although landraces of wheat are no longer grown in Europe and North America, they continue to be important elsewhere. The origins of formal wheat breeding lie in the nineteenth century, when single line varieties were created through selection of seed from a single plant noted to have desired properties. Modern wheat breeding developed in the first years of the twentieth century and was closely linked to the development of Mendelian genetics. The standard method of breeding inbred wheat cultivars is by crossing two lines using hand emasculation, then selfing or inbreeding the progeny. Selections are identified (shown to have the genes responsible for the varietal differences) ten or more generations before release as a variety or cultivar.[14] Landrace refers to domesticated animals or plants adapted to the natural and cultural environment in which they live (or originated) and, in some cases, work; they often develop naturally with minimal assistance or guidance from humans (or from humans using traditional rather than modern breeding methods), hence differ somewhat from... Mendelian inheritance (or Mendelian genetics or Mendelism) is a set of primary tenets that underlie much of genetics developed by Gregor Mendel in the latter part of the 19th century. ... F1 hybrid wheat cultivars should not be confused with wheat cultivars deriving from standard plant breeding. Heterosis or hybrid vigor (as in the familiar F1 hybrids of maize) occurs in common (hexaploid) wheat, but it is difficult to produce seed of hybrid cultivars on a commercial scale as is done with maize because wheat flowers are complete and normally self-pollinate.[14] Commercial hybrid wheat seed has been produced using chemical hybridizing agents, plant growth regulators that selectively interfere with pollen development, or naturally occurring cytoplasmic male sterility systems. Hybrid wheat has been a limited commercially success, in Europe (particularly France), the USA and South Africa.[15] http://www.indiatogether.org/2009/sep/dsh-borlaug.htm 23 September 2009 - It was discovery of the stocky Japanese wheat variety Norin-10, which the US military advisor D C Salmon sent back home in the early 1960s that changed the face of global agriculture. This was the variety, the only known semi-dwarf traditional wheat strain, that Dr Norman Borlaug was keenly looking for. Crossed with the rust-resistant varieties that Borlaug had developed at the International Centre for Wheat and Maize Research (CIMMYT) in Mexico, the world got the miracle improved varieties that made history. These semi-dwarf plants developed by Dr Borlaug responded to the application of chemical fertilisers and produced a bountiful grain harvest. The yields multiplied under favourable conditions, and Borlaug knew that the best place to apply the new technology was obviously India, with the largest population of hungry and starved in the world. "I tried my best to convince the Indian politicians about the utility of these semi-dwarf varieties in fighting hunger, but they were not interested," he once told me. Although the agricultural scientists, by and large, were convinced about the yield potential of these varieties, the politicians were not. ---------------- Dr Borlaug remained steadfast all through on the role of chemical fertiliser and pesticides. He was so adamant that when the Third World Academy in Italy presented a paper on how Brazil had achieved remarkable crop yields in soybean and sugarcane without applying chemical nitrogen, he didn't agree. It was only after he travelled to Brazil and saw for himself the crop yields that he at least acknowledged the reality. But even then, he wouldn't accept agriculture without chemical fertilisers and pesticides. Such was his blind faith in plant breeding that initially he even rejected biotechnology, saying it was a 'waste of time." Later, he backed genetic engineering. http://www.eeob.iastate.edu/faculty/WendelJ/pdfs/Current%20Genomics%202002.pdf Many important crop plants, including wheat, oat, coffee, potato, canola, soybean, sugarcane, tobacco and cotton are typical polyploids. Because most ancient polyploids have undergone an evolutionary process of chromosomal and perhaps genic “diploidization”, their polyploid history may be obscured at the cytological and classic genetics levels. Consequently, the polyploid nature of many plant genomes was not evident until the advent of comparative genomics and whole-genome sequencing. Recent and prominent examples include maize [17,18] and Arabidopsis [19-21] — both species were traditionally recognized as diploids, but in fact their genomes harbor compelling evidence of historical cycles of genome doubling. Given these and other recent examples from plants [e.g. 22,23-26], it is probably safe to state that there are no bona fide diploid species in the plant kingdom. Perhaps of more significance, the young (~ 8,500 year-old) natural hexaploid species Triticum aestivum (common or bread wheat), vital to the development and present sustenance of human civilization, is a classic example of speciation via allopolyploidy. This species is an allohexaploid, with a genomic constitution BBAADD, formed from a natural hybridization event between the allotetraploid Triticum turgidum (BBAA) and a taxon similar to modern Aegilops tauschii (DD), with genome doubling most probably resulting from fertilization between unreduced gametes [37,38]. http://www.weizmann.ac.il/plants/levy/hybridity.html Hybridity and Polyploidy Interspecies hybridization and polyploidy are prominent in the plant kingdom. Wheat for example is an hexaploid, whose genome is an hybrid combining the genome of three diploid progenitors. Polyploidization can occur overnight, for example through inter-specific hybridization followed by genome doubling via unreduced gametes. It is thus one of the most efficient and rapid way to generate a new species and is a driving force in plant genome evolution. The paradigm to explain the success of polyploidy was that the increased range of gene dosage, the new heterotic interactions between alleles, homeoalleles or genes and the buffering of the mutation load resulting from gene duplication facilitate the formation of novel genes and the establishment of the new species. While this long-held view is still valid, there are now new twists to the paradigm. Recent studies done in collaboration with Prof. Moshe Feldman, have emphasized the importance of non-Mendelian processes and described their time course. In these studies, synthetic polyploids were made and analyzed immediately after formation. These studies show that a new, non-additive variation, not previously present in the diploid progenitors, can be induced immediately upon polyploidization rather than on an evolutionary scale. The basis of this new variation is both genetic and epigenetic. The types of non-Mendelian changes observed were: programmed elimination of sequences (coding and non-coding); gene silencing associated with cytosine methylation and transcriptional activation of retrotransposons. These findings were confirmed by a recent bioinformatics analysis using public data on the mapping and expression of DNA sequences in natural hexaploid wheat rather than in synthetic polyploids. This rapid reorganization of the genome structure and expression is now investigated in wheat as well as in model systems, Arabidopsis and budding yeast. The current work in wheat aims at determining the precise time course and the mechanism of programmed DNA elimination. In Arabidopsis, we are making use of a new method of gene targeting recently developed in our laboratory to follow the expression of alleles as a function of hybridity and of gene dosage variation achieved through polyploidization. We expect that epigenetic changes will be triggered as a result of hybridity and/or polyploidization, that may lead to the silencing of specific alleles. In budding yeast, we are collaborating with Prof. Naama Barkai to analyze the new patterns of gene expression in yeast hybrids and in polyploids derived from interspecific crosses. Moreover, we are analyzing the genetic basis for the heterosis (Hybrid vigor) that has been observed in some of the hybrids. http://www.marxistsfr.org/reference/archive/lysenko/works/1950s/new.htm In 1949 a search for rye grains in wheat spikes was instituted in the fields of the foothill districts where winter-wheat crops are frequently found to be adulterated with rye. Until a few years ago scientists did not know the original cause of such adulteration in these districts. V. K. Karapetian, M. M. Yakubtsiner, V. N. Gromachevsky and a number of other research workers as well as a number of agronomists and students found single grains of rye in durum- and soft-wheat spikes, i.e., in the spikes of two wheat species which grew in the fields of various foothill districts. Over 200 such grains of rye were found in 1949. These grains were sown at the Institute of Genetics of the Academy of Sciences of the U.S.S.R., in an experimental field of the Lenin Academy of Agricultural Sciences of the U.S.S.R. at Gorki Leninskiye, and at the K. A. Timiryszev Agricultural Academy in Moscow. Unthreshed spikes of durum and soft wheat were likewise sent to the Lenin Academy of Agricultural Sciences of the U.S.S.R. from the districts mentioned. While they were being threshed at different biological research institutions several persons found some more grains of rye. >From these grains of rye, which had developed in spikes of durum and soft wheat, a diversity of plants was grown. These plants, with few exceptions, were neverthleless typical rye. Only in a very few cases were wheat plants obtained from rye-like grains. In all the above cases where grains of one species of plant were found in spikes of neither species neither the plants themselves nor their threshed spikes showed any signs whatever of being intermediate forms. They seemed to be typical, ordinary spikes of durum or soft wheat. But the internal state of these wheat plants was no longer the usual one, was no longer qualitatively homogeneous in respect to species. This is indicated by the fact that these wheat grains produced not only grains of wheat but also some few grains of rye, that is, grains of another species. In 1949 the Lenin Academy of Agricultural Sciences of the U.S.S.R. received samples of oats whose panicles contained single grains of wild oats alongside of the grains of cultivated oats, that is to say, the plants of one species, Avena sativa, brought forth individual grains of another species, A. fatua. Publications abroad as well as in our country have likewise repeatedly referred to cases where wild oats were found in pure-line oats. It has been observed year after year when cultivating branched wheat (Triticum turgidum) on experimental plots of the Lenin Academy of Agricultural Sciences of the U.S.S.R. and in a number of other localities that admixtures of soft and durum wheat, oats, 2- and 4-rowed barley and also spring rye appear in the crops. All our observations led us to conclude that the original source of these admixtures was the branched wheat (Triticum turgidum) itself. In 1950 it was discovered in several cases that barley plants which were growing as an admixture in branched-wheat crops had developed from grains which in external appearance could not be distinguished from branched-wheat grains. In practical farming it has long been assumed and repeatedly asserted that one kind of agricultural plant can be converted or transformed into another, as for instance wheat into rye. A great controversy was waged in print on this subject in our country as early as the first half of the previous century. Therefore the conversion of durum wheat into soft or the conversion of durum and soft wheat into rye would seem by itself to be nothing new. However, all the new facts we have adduced were obtained in a systematic way or as the result of a systematic search. As regards the past, before our investigation started, the facts were as follows. In fields sown to durum wheat individual plants of soft wheat were discovered. When this wheat was resown the soft-wheat plants multiplied more and more and finally ousted the durum wheat. Similarly, individual rye plants were found amidst winter wheat. When the seeds obtained from crops grown in such fields were resown the rapidly multiplying rye plants pushed out the wheat. But scientists refused as a matter of principle to consider any such discoveries of plants of one species in the stands of other species as a result of the conversion of one species into another. Legitimate doubts were always voiced. It was not established whether or not the prime cause of this adulteration was ordinary mechanical admixture so frequently met with. There was no assurance that the original seeds really did not contain an admixture of a few seeds of another species, or that seeds of another species had not been carried to the sown field in question by water, wind, birds or some other agency; nor could one be sure that seeds of the admixed breed had not been in the soil of that field for a long period of time, etc. This explains why it was impossible to prove by facts relating to the past that the emergence of one plant species from another species might also be an original source of the various crop admixtures and adulterations, besides their frequent introduction into crops by mechanical means. All the enumerated objections to the idea of one species giving rise to another become invalid in the cases referred to by us. Individual grains of rye discovered in spikes of wheat which had grown for several generations under definite conditions could not possibly have been introduced into these spikes from without by either birds or man or in any other way. These grains of rye were generated by wheat plants and developed in spikes of wheat. The supposition that these seeds might be of hybrid origin also goes by the board. It is a known fact that wheat can be crossed with rye, though seldom. However, in these cases the product obtained is an obvious rye-wheat hybrid which can readily be distinguished from wheat and rye by its external appearance. Besides, rye-wheat hybrids, as a rule, are self-sterile; they yield no seeds unless they are pollinated with the pollen of one of their parents, preferably the wheat. In the case at hand the grains of rye from the wheat spikes produced ordinary rye plants with normal fertility. The said plants manifested no hybrid properties whatever. The same applies to the other facts we have mentioned. The above examples of the generation of particular plant species by others are particularly valuable because analogous cases may be observed any year in suitable fields. Similar results may likewise be obtained by cultivating plants specially sown under experimental conditions for this purpose. http://en.wikipedia.org/wiki/Triticale When crossing wheat and rye, wheat is used as the female parent and rye as the male parent (pollen donor). The resulting hybrid is sterile and has to be treated with colchicine to induce polyploidy and thus able to reproduce itself. The primary producers of triticale are Poland, Australia, Germany, France, China and Belarus. In 2005, according to the Food and Agriculture Organization (FAO), 13.5 million tons were harvested in 28 countries across the world.[citation needed] The triticale hybrids are all amphidiploid, which means the plant is diploid for two genomes derived from different species. In other words, triticale is an allotetraploid. In earlier years most work was done on octoploid triticale. Different ploidy levels have been created and evaluated over time. The tetraploids showed little promise, but hexaploid triticale was successful enough to find commercial application.[citation needed] _______________________________________________ Marxism-Thaxis mailing list [email protected] To change your options or unsubscribe go to: http://lists.econ.utah.edu/mailman/listinfo/marxism-thaxis
