Early Holocene cultivation before domestication in northern Syria

Charred plant remains from the sites of Tell Qaramel, Jerf el Ahmar, Dja’de and Tell ‘Abr situated in northern Syria and dated to the tenth and ninth millennia cal b.c. demonstrate that a wide variety of wild pulses, cereals, fruits and nuts was exploited. Five lines of evidence suggest that cultivation was practised at three of the sites. (1) Wild einkorn, wild rye and lentils occur outside their natural habitats. (2) The founder crops barley, emmer and single-grained einkorn appear at different times. (3) An assemblage of weeds of cultivation was identified. (4) There is a gradual decrease in gathered plants such as small seeded grasses and Polygonum/Rumex. (5) Barley grains increase in breadth and thickness. Morphological domestication did not become established, perhaps because seed stock was regularly collected from wild stands. Charred rodent droppings indicate large-scale grain storage.     

Pulse domestication and cereal domestication: How different are they?

Evidence is brought to indicate that the domestication of lentil and pea is not very different from that of wheat and barley. All these Near East crops are characterized by basically the same domestication traits the key elements of which are breakdown of the wild mode of seed dispersal and loss of germination regulation. It is argued that both in the pulses and in the cereals these traits evolved in the same way. The changes are best explained by assuming that mutations causing the loss of the wild-type adaptations were automatically selected for soon after people transferred the wild progenitors into a system of planting and reaping.     

Modelling the origins of legume domestication and cultivation

Ladizinsky’s (1987) mathematical model of the domestication of lentils and other Near Eastern legumes is invalid. Ladizinsky believed that the model predicts that high rates of seed harvesting would lead to fixation, in wild populations, of genes conferring lack of seed dormancy (a domesticated trait). In fact, however, the model gives rapid fixation of alleles for non-dormancy underall circumstances; gathering by humans has no effect on allelic frequencies. It appears that in these species cultivation must have preceded the morphological changes that distinguish domesticated from wild plants. The addition of more realistic assumptions to the model does not alter this conclusion. I suggest several scenarios that could explain Near Eastern legume domestication: the most plausible of these postulates that cultivation of cereals led to scheduling conflicts which necessitated the abandonment of harvesting of wild legumes, and hence the initiation of their cultivation. Mathematical modelling may be able to contribute to our understanding of agricultural origins, but it must be carried out with greater rigor and closer attention to the theoretical literature.     

The domestication of Amazonia before European conquest

During the twentieth century, Amazonia was widely regarded as relatively pristine nature, little impacted by human history. This view remains popular despite mounting evidence of substantial human influence over millennial scales across the region. Here, we review the evidence of an anthropogenic Amazonia in response to claims of sparse populations across broad portions of the region. Amazonia was a major centre of crop domestication, with at least 83 native species containing populations domesticated to some degree. Plant domestication occurs in domesticated landscapes, including highly modified Amazonian dark earths (ADEs) associated with large settled populations and that may cover greater than 0.1% of the region. Populations and food production expanded rapidly within land management systems in the mid-Holocene, and complex societies expanded in resource-rich areas creating domesticated landscapes with profound impacts on local and regional ecology. ADE food production projections support estimates of at least eight million people in 1492. By this time, highly diverse regional systems had developed across Amazonia where subsistence resources were created with plant and landscape domestication, including earthworks. This review argues that the Amazonian anthrome was no less socio-culturally diverse or populous than other tropical forested areas of the world prior to European conquest.     

薄皮干酪菌生物学特性及驯化栽培

大型真菌种质资源是国家种质资源库建设重要组成部分,为了充分开发利用大型真菌资源,对采自吉林省寒葱岭的一株野生菌进行分离纯化,并将获取的纯菌株作为实验材料。通过形态学和ITS序列分析,将其鉴定为薄皮干酪菌Tyromyces chioneus。本实验研究了固体培养条件下不同碳源、氮源、pH和温度对其菌丝生长的影响,并从4个单因素实验中选出3个最优水平进行正交实验。同时,在对其菌丝体最适培养条件研究结果的基础上,对其进行驯化栽培研究。结果表明,薄皮干酪菌的最适培养条件为：果糖(20 g/L)、酵母浸粉(2 g/L)、pH 4.0、温度30 ℃。正交实验结果表明,氮源对其菌丝体生长的影响最大,其次是碳源、pH和温度。驯化栽培结果表明,菌丝发菌时间为21 d;空气湿度为85%-95%,适量的散射光,降低温度至18-20 ℃刺激后原基逐步变成菇蕾,将温度、湿度分别提高至24-25 ℃、90%-98%,30 d后子实体成熟。通过本实验的研究为薄皮干酪菌的后续开发利用提供了基础实验数据。     

迷宫栓孔菌生物学特性、驯化栽培及抗氧化活性

迷宫栓孔菌在药用上具有降血糖的功效,分布广泛,对采自吉林省白山市露水河镇红松王景区的迷宫栓孔菌Trametes gibbosa进行组织分离,得到菌株ZT-055,对其菌丝体最适培养条件和子实体驯化栽培进行研究,并测定栽培子实体的多糖抗氧化活性。在单因素试验基础上的正交试验结果表明：迷宫栓孔菌最适生长条件是碳源为果糖、氮源为酵母浸粉、温度为30℃、pH值为5.0;栽培试验中,通过17d的发菌,于30d左右开始形成原基,44d原基分化成菇蕾,57d左右形成成熟子实体;采用水提醇沉法提取多糖,苯酚-硫酸法测定多糖含量,结果表明迷宫栓孔菌ZT-055子实体多糖含量约为(80.51±5.1)mg/g,在多糖浓度为1.26mg/mL条件下,羟自由基清除率达到45%,超氧氢离子清除率达到48%,表明该菌具有较高的抗氧化活性。     

四株野生毛木耳的生物学特性分析及驯化栽培

优质菌种是食用菌产业持续健康发展的基础。毛木耳野生种质资源丰富,可作为新种质创制和品种选育的重要来源。为丰富毛木耳的育种材料,本研究以采自中国、俄罗斯和赞比亚3个国家的4株野生木耳菌株为材料,进行了基于内转录间隔区序列(ITS)的分子系统发育鉴定、生物学特性分析及出菇品比试验。结果表明：4株野生木耳菌株均为毛木耳;菌丝体最适碳源各不相同,最适氮源为酵母粉或氯化铵,最适pH为7-9,最适温度为25-30 ℃;所有菌株均可驯化出菇,其中赞比亚菌株Ⅲ的发菌速度最快,且第一茬鲜重高于国内栽培菌株(Ⅴ和Ⅵ),俄罗斯菌株Ⅰ最先产生原基。本研究获得的4株野生毛木耳菌株,在营养需求、出菇形态、产量和生育期等农艺性状上均存在差异,为毛木耳育种工作提供了新的资源。     

Ustilago maydis populations tracked maize through domestication and cultivation in the Americas

The domestication of crops and the development of agricultural societies not only brought about major changes in human interactions with the environment but also in plants' interactions with the diseases that challenge them. We evaluated the impact of the domestication of maize from teosinte and the widespread cultivation of maize on the historical demography of Ustilago maydis, a fungal pathogen of maize. To determine the evolutionary response of the pathogen's populations, we obtained multilocus genotypes for 1088 U. maydis diploid individuals from two teosinte subspecies in Mexico and from maize in Mexico and throughout the Americas. Results identified five major U. maydis populations: two in Mexico; two in South America; and one in the United States. The two populations in Mexico diverged from the other populations at times comparable to those for the domestication of maize at 6000-10000 years before present. Maize domestication and agriculture enforced sweeping changes in U. maydis populations such that the standing variation in extant pathogen populations reflects evolution only since the time of the crop's domestication.     

Genetic analysis of wheat domestication and evolution under domestication

Wheat is undoubtedly one of the world's major food sources since the dawn of Near Eastern agriculture and up to the present day. Morphological, physiological, and genetic modifications involved in domestication and subsequent evolution under domestication were investigated in a tetraploid recombinant inbred line population, derived from a cross between durum wheat and its immediate progenitor wild emmer wheat. Experimental data were used to test previous assumptions regarding a protracted domestication process. The brittle rachis (Br) spike, thought to be a primary characteristic of domestication, was mapped to chromosome 2A as a single gene, suggesting, in light of previously reported Br loci (homoeologous group 3), a complex genetic model involved in spike brittleness. Twenty-seven quantitative trait loci (QTLs) conferring threshability and yield components (kernel size and number of kernels per spike) were mapped. The large number of QTLs detected in this and other studies suggests that following domestication, wheat evolutionary processes involved many genomic changes. The Br gene did not show either genetic (co-localization with QTLs) or phenotypic association with threshability or yield components, suggesting independence of the respective loci. It is argued here that changes in spike threshability and agronomic traits (e.g. yield and its components) are the outcome of plant evolution under domestication, rather than the result of a protracted domestication process. Revealing the genomic basis of wheat domestication and evolution under domestication, and clarifying their inter-relationships, will improve our understanding of wheat biology and contribute to further crop improvement.     

Colours of domestication

During the last decade, coat colouration in mammals has been investigated in numerous studies. Most of these studies addressing the genetics of coat colouration were on domesticated animals. In contrast to their wild ancestors, domesticated species are often characterized by a huge allelic variability of coat‐colour‐associated genes. This variability results from artificial selection accepting negative pleiotropic effects linked with certain coat‐colour variants. Recent studies demonstrate that this selection for coat‐colour phenotypes started at the beginning of domestication. Although to date more than 300 genetic loci and more than 150 identified coat‐colour‐associated genes have been discovered, which influence pigmentation in various ways, the genetic pathways influencing coat colouration are still only poorly described. On the one hand, similar coat colourations observed in different species can be the product of a few conserved genes. On the other hand, different genes can be responsible for highly similar coat colourations in different individuals of a species or in different species. Therefore, any phenotypic classification of coat colouration blurs underlying differences in the genetic basis of colour variants. In this review we focus on (i) the underlying causes that have resulted in the observed increase of colour variation in domesticated animals compared to their wild ancestors, and (ii) the current state of knowledge with regard to the molecular mechanisms of colouration, with a special emphasis on when and where the different coat‐colour‐associated genes act.     

Toward the domestication of lignocellulosic energy crops: learning from food crop domestication

Domestication of cereal crops has provided a stable source of food for thousands of years. The extent to which lignocellulosic crops will contribute to the world's renewable energy depends largely on how the new crops will be domesticated. Growing miscanthus as biofuel feedstocks on marginal and degraded land in northern and northwestern China offers an example for developing theoretical framework and practical strategies for energy crop domestication. The domestication should incorporate the highest possible genetic diversity from wild species, focus on the improvement of drought and cold tolerance especially in the stage of crop establishment, increase the efficiencies of water and nutrient uses and photosynthesis, adjust vegetative growing season according to local temperature and precipitation, and reduce or prevent seed production. Positive ecological effects on soil conservation, landscape restoration, carbon sequestration, and hydrological cycles should be maximized, while negative impact on biodiversity needs to be minimized. With the development of other sources of renewable energy, the role of lignocellulosic crops may evolve from primarily energy production to increasingly ecological restoration and biomaterial development. The integration of this new cropping system into the existing agriculture may open a new avenue to the long-term sustainability of our society.     

The process of domestication

Domestication involves both culture and biology. The cultural process of domestication begins when animals are incorporated into the social structure of a human community and become objects of ownership, inheritance, purchase and exchange. The morphological changes that occur in domestic animals come second to this integration into human society. The biological process resembles evolution and begins when a small number of parent animals are separated from the wild species and are habituated to humans. These animals form a founder group, which is changed over successive generations, in response to natural selection under the new regime imposed by the human community and its environment, and also by artificial selection for economic, cultural, or aesthetic reasons. In the wild, the evolution of a subspecies occurs when a segment of a species becomes reproductively isolated by a geographical barrier. With domestic animals, this separation leads to the development of different breeds.     

Evolution of polyploid triticum wheats under cultivation: the role of domestication, natural hybridization and allopolyploid speciation in their diversification

The evolution of the polyploid Triticum wheats is distinctive in that domestication, natural hybridization and allopolyploid speciation have all had significant impacts on their diversification. In this review, I outline the phylogenetic relationships of cultivated wheats and their wild relatives and provide an overview of the recent progress and remaining issues in understanding the genetic and ecological factors that favored their evolution. An attempt is made to view the evolution of the polyploid Triticum wheats as a continuous process of diversification that was initiated by domestication of tetraploid emmer wheat and driven by various natural events ranging from interploidy introgression via hybridization to allopolyploid speciation of hexaploid common wheat, instead of viewing it as a group of discrete evolutionary processes that separately proceeded at the tetraploid and hexaploid levels. This standpoint underscores the important role of natural hybridization in the reticulate diversification of the tetraploid-hexaploid Triticum wheat complex and highlights critical, but underappreciated, issues that concern the allopolyploid speciation of common wheat.     

The domestication of American wildrice

The expansion in wildrice (Zizania palustris) production and the associated research efforts represent the largest modern effort to domesticate a cereal grain. Wildrice growers brought the species under cultivation, but plant breeding and agronomic research have accelerated the domestication process. The domestication and commercialization of this diploid (2n = 30), protogynous, cross-pollinated, annual, aquatic cereal present an opportunity to examine crop evolution and domestication theory. Traits associated with the domesticated cereal grains are shattering resistance, tiller synchrony, and increased seed size. This syndrome of traits may result from automatic selection, the selective force applied by repeated cycles of planting of harvested seed. Positive responses from deliberate selection for these traits in wildrice populations indicate that a domestication ideotype is attainable through plant breeding and that founder effect in this diploid species may be negligible. Continued commercial production of wildrice in the Great Lakes region is not likely to further the domestication process, whereas automatic selection may be initiated in the emerging California wildrice industry.     

Genetic analysis of sunflower domestication

Quantitative trait loci (QTL) controlling phenotypic differences between cultivated sunflower and its wild progenitor were investigated in an F(3) mapping population. Composite interval mapping revealed the presence of 78 QTL affecting the 18 quantitative traits of interest, with 2-10 QTL per trait. Each QTL explained 3.0-68.0% of the phenotypic variance, although only 4 (corresponding to 3 of 18 traits) had effects >25%. Overall, 51 of the 78 QTL produced phenotypic effects in the expected direction, and for 13 of 18 traits the majority of QTL had the expected effect. Despite being distributed across 15 of the 17 linkage groups, there was a substantial amount of clustering among QTL controlling different traits. In several cases, regions influencing multiple traits harbored QTL with antagonistic effects, producing a cultivar-like phenotype for some traits and a wild-like phenotype for others. On the basis of the directionality of QTL, strong directional selection for increased achene size appears to have played a central role in sunflower domestication. None of the other traits show similar evidence of selection. The occurrence of numerous wild alleles with cultivar-like effects, combined with the lack of major QTL, suggests that sunflower was readily domesticated.