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1.
Feral populations of domesticated crops can establish through two nonmutually exclusive pathways: hybridization with native relatives and recruitment of and recombination between known cultivars. The extent and relative importance of these pathways is not known, especially for woody fruit crops. Here, we examined the evolutionary origins of feral populations of Malus domestica (domestic apple) in southern Canada using a population genetic analysis. We characterized genotypes of 578 putative feral apple trees and evaluated them in relation to genotypes of 156 commercial cultivars, 28 non‐native, ornamental crabapples and 47 native Malus coronaria trees using 14 microsatellite markers. No feral trees were genetic admixtures between domestic and native Malus; however, a minority of trees were admixed with introduced ornamental Malus. Feral trees and commercial cultivars both occurred in two major genetic groups and seven subgroups distributed throughout all commercial growing regions. A total of 42 cultivars, both heritage and currently grown, occurred in probable parental pairs for feral trees, with nine heritage varieties accounting for 72% of parental assignments. We conclude that feral apples in southern Canada are not products of hybridization with native M. coronaria but we cannot exclude ornamental apple species as contributing to the naturalization process. Nonhybrid feral domestic apples have multiple origins, with a prominent signature of early heritage cultivars. These lineages have spread and coexist throughout Ontario, rather than being derived strictly from local sources. 相似文献
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The American bullfrog (Lithobates catesbeianus), considered as one of the world’s worst invasive species because of its negative effects on native fauna, has been introduced
into over 40 countries in four continents. The invasion status in Mexico is poorly known. The first known record for this
species in the Peninsula of Baja California, northwestern Mexico is an individual collected 35 years ago. A great portion
of the peninsula is an arid desert where the sources of freshwater are the spring-fed oasis and mountain arroyos that support
rare and endemic species closely associated with wetland conditions. Humans, who have introduced alien species, inhabit many
of those oases. The aim of this work was to document the presence of the exotic bullfrog in 40 oases and mountain arroyos
in Baja California Sur state during 2006–2009. Bullfrogs were found in 25% of the oases sampled; 15% have confirmed records
of breeding populations and five oases are new location records. Our results show a considerable increase (50%) in the number
of oasis invaded by bullfrogs in only 8 years. The animal populations of rare or endemic species associated with oases would
be threatened by the arrival of bullfrogs. Actions for their control and eradication are urgently needed. 相似文献
3.
Iconic to the Mediterranean landscape, the age of monumental olive trees with large trunks and unique silhouettes is often considered several centuries to millennia. Here we combine tree-ring and radiocarbon dating to show that most monumental olive trees may have maximum ages between 300 and 500 years. Our example helps disentangling the tree size-longevity conundrum in a major Mediterranean cultivated tree species and important cultural heritage. 相似文献
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Prof. Dr. Andreas Bürkert Sulaiman Al Khanjari Nadiya A. Al‐Saady Edmond De Langhe Dirk Hölscher Jens Gebauer Stephan Behrendt Stefan Happe Katja Brinkmann Eva Schlecht 《当今生物学》2010,40(5):334-341
Until recently little was known about the crop diversity in the Sultanate of Oman, situated at the NE tip of the Arabian Peninsula. Interdisciplinary research in the often millenia‐old oases provide evidence for their role as reservoirs for plant genetic resources of ancient varieties of wheat and banana. Two newly discovered banana clones show a highly efficient biochemical defense mechanisms against some of the most devastating pests and diseases of banana. If these mechanisms can be properly understood and exploited in breeding programs, may have major impact on the commercial production of edible banana. 相似文献
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Mohamed Abdel Aziz Balah 《农业工程》2019,39(1):14-20
Oases are a specific ecosystems which date palm Phoenix dactylifera are the mainly crop growing for its fruits and others tree parts. Palm orchards are infested by many pests, including weeds species and exposed within time to the challenging invasive weeds to control. The heavy incidence of weeds negatively affects palm productivity, especially in small plantation and divergent distances, while the established orchards, palm trees shading cause deprives from the process of weeds photosynthesis to be lower competitive. The survey was conducted in El-Bahariya and El-Frafra than Siwa oases of which 375 plots were taken. Vegetative analysis in oases altogether demonstrate 91 weed specimens were encountered of which 18 perennial, 42 were broad leaved, and 30 narrow leaved as well as one parasitic weed species belonging to 22 families, whereas Poaceae is the most plentiful family displayed by 38.5% from all families, occurred in date palm orchards during the study. The geographical differentiation affected coefficient of similarity whereas, it in oases recorded the highest between El-Bahariya and El-Frafra than Siwa and El-Bahariya, while El-Frafra Oasis was the most diverse and richness than the others which have the middle soil properties, fertility, and structure. The correlation analysis of weed flora between both El-Bahariya and El-Frafra was higher and more than El-Bahariya and Siwa oases. Under the unique closed agroenvironment of oases, weeds population dynamics are a stable approximately. Regardless of the diversity of annual weed species, perennials species represent the highest dominant number and the pattern of grown weeds was more dominant than wild desert and some invasive weed species. The control action should be taken of perennial weeds and proactive as well as long term prevention for invasive species. 相似文献
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R. García M. J. Asíns J. Forner E. A. Carbonell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):511-518
Propagation of citrus rootstocks depends upon the production of clonal plants from nucellar seedlings. This makes apomixis
one of the host important traits in breeding programs for citrus rootstocks. The genetic control of apomixis was studied in
a 50-tree progeny derived from the cross C. volkameriana×P. trifoliata using 69 molecular markers and bulked segregant analysis. The proportion of nucellar seedlings was estimated by isoenzymatic
analysis of 25 seedlings per tree for 2 consecutive years. The type of embryony (polyembryonic versus monoembryonic seeds)
was also determined for fruit-yielding trees. Separate genetic maps for each parental species were developed. The integration
and comparison of these maps could be accomplished using common multiallelic segregant loci. Differences in gene synteny between
the two species-specific genetic maps were shown. Important distortions in the segregation of markers at several genomic regions,
some of them also involving differences in the C-methylation pattern, have been observed, especially for the pollen parent.
Analysis of quantitative trait loci (QTLs) revealed the presence of six genomic positions (two in P. trifoliata and four in C. volkameriana) contributing individually up to 24% of the total variation for apomixis. Within the same species, QTLs with positive and
negative allele effects were present, even in the same linkage group. One of the markers associated to apomixis (Apo2) is also associated to embryony type. Therefore, the genetic control of apomictic reproduction found in citrus (nucellar
embryony) is quite complex compared to what has been reported for gametophytic apomixis. Molecular markers linked to QTLs
governing apomixis will be useful to assist selection of future apomictic rootstocks for citrus varieties.
Received: 30 November 1998 / Accepted: 28 December 1998 相似文献
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In citrus despite the diversity among cultivated genotypes related to morphological, physiological, and agronomic traits, low polymorphism is detected at the molecular marker level, and the number of DNA-markers technologies has been insufficient to identify genetic diversity among all citrus varieties. However, DArT_seq? markers can overcome this limitation and identify genetic diversity in several species of citrus. This work developed and applied DArT_seq? platform to study the relationships among species, cultivars, and hybrids of citrus. DArT_seq? yielded a total of 37,260 polymorphic presence/absence markers that generated a dendrogram of similarity among the studied genotypes. The results confirmed the relationships of sweet orange, mandarin, and citron species. DArT_seq? markers showed extensive genetic variation among citrus species and can be applied to Citrus genetic diversity studies. 相似文献
11.
《Fungal Biology Reviews》2020,34(3):126-135
Fungi are one of the main agents responsible for the biodeterioration of cultural heritage through physical and chemical processes. The frequent isolation of certain fungal species from deteriorated materials indicates that these species appear to have a particular affinity for environmental conditions occurring in cultural heritage. It is important to identify the conditions that favour the development of such species in order to understand how to preserve monuments and collections. Among these fungal species, the involvement of Parengyodontium album (Limber) Tsang et al. seems to have been underestimated until now. This species is abundant in many environments and its taxonomic position has changed quite frequently, which may have concealed the effect of this fungus on cultural heritage sites. This review seeks to compile the involvement of P. album in cultural heritage biodeterioration phenomena under all the names that it has been attributed in order to effectively determine its occurrence. This paper also aims to determine whether P. album is marginal or dominant when detected on materials. Finally, the conditions that favour the development of P. album on cultural heritage objects and sites are discussed. 相似文献
12.
Constitutive expression of Arabidopsis LEAFY or APETALA1 genes in citrus reduces their generation time 总被引:23,自引:0,他引:23
Peña L Martín-Trillo M Juárez J Pina JA Navarro L Martínez-Zapater JM 《Nature biotechnology》2001,19(3):263-267
Citrus trees have a long juvenile phase that delays their reproductive development by between 6 and 20 years, depending on the species. With the aim of accelerating their flowering time, we transformed juvenile citrus seedlings to constitutively express the Arabidopsis LEAFY (LFY) or APETALA1 (AP1) genes, which promote flower initiation in Arabidopsis. Both types of transgenic citrus produced fertile flowers and fruits as early as the first year, notably through a mechanism involving an appreciable shortening of their juvenile phase. Furthermore, expression of AP1 was as efficient as LFY in the initiation of flowers, and did not produce any severe developmental abnormality. Both types of transgenic trees flowered in consecutive years, and their flowering response was under environmental control. In addition, zygotic and nucellar derived transgenic seedlings had a very short juvenile phase and flowered in their first spring, demonstrating the stability and inheritance of this trait. These results open new possibilities for domestication, genetic improvement, and experimental research in citrus and other woody species. 相似文献
13.
Over the last two decades, the importance of conserving genetic resources has received increasing attention. In this context
the role of home gardens as repositories of biological diversity has been acknowledged but still a comprehensive, interdisciplinary
investigation of their agro-biodiversity is lacking. Home gardens, whether found in rural or urban areas, are characterized
by a structural complexity and multifunctionality which enables the provision of different benefits to ecosystems and people.
Studies carried out in various countries demonstrate that high levels of inter- and intra-specific plant genetic diversity,
especially in terms of traditional crop varieties and landraces, are preserved in home gardens. Families engage in food production
for subsistence or small-scale marketing and the variety of crops and wild plants provides nutritional benefits. At the same
time, home gardens are important social and cultural spaces where knowledge related to agricultural practices is transmitted
and through which households may improve their income and livelihoods. The present article summarizes available literature
on the biological and cultural significance of agro-biodiversity in home gardens. It discusses future constraints and opportunities
in home garden research, in the prospect of defining and promoting their role in conservation of agricultural biodiversity
and cultural heritage. 相似文献
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槭属植物是世界园林绿化中的重要植物种类,种质资源丰富且大多数种类具有重要的观赏价值。针对目前我国槭属植物杂交育种工作中面临的品种混杂不清、亲缘状况不明等情况,该研究采用ISSR分子标记对槭属25份植物材料进行了亲缘关系分析。结果表明:选用12条扩增带型清晰且重复性好的引物共获得84条谱带,其中81条呈多态性,多态性比例(PPB)达96.43%,表明槭属植物遗传多样性较高。25份槭属植物材料的遗传相似性系数介于0.405与0.952之间,平均值为0.627,表明不同品种或物种之间遗传相似性系数变化较大。根据Nei遗传相似性系数,在0.578处,UPGMA结果将25份植物材料分为2个类群,其中鸡爪槭品种(或变种)聚为一类,显示了各品种(或变种)之间具有较高的亲缘关系,其余槭属植物则聚为类群II;在0.646处,可进一步分为6个亚类群,部分鸡爪槭品种间表现出了叶形、叶色等表型形状与其遗传关系的相关性。研究未发现鸡爪槭品种(或变种)的亲缘关系与地理分布存在相关性。我国槭树资源丰富,但目前我国对槭树新品种的开发及选育工作仍十分薄弱,建议采取自行选育结合国外引进新品种的方式,丰富我国的槭树种质资源。 相似文献
16.
An inventory was made of 50 ha of primary lowland rain forest in Peninsular Malaysia, in which ca. 340,000 trees 1 cm dbh or larger were measured and identified to species. Out of a total plot tree flora of 820 species, 76 species are known to bear edible fruit. Especially diverse were the wild species of mango (Mangifera, Anacardiaceae, 12 spp.), mangosteen (Garcinia, Clusiaceae, 13 spp.), breadfruit (Artocarpus, Moraceae, 10 spp.) and rambutan (Nephelium, Sapindaceae, 5 spp.). Median population size for all species of fruit trees was 3.0 trees per ha and 0.2 adult trees per ha. Direct economic value of wild fruit trees was small; only one species has been very much collected and sold, Parkia speciosa (Fabaceae), amounting to less than US$20 per ha per year. The potential value of the species as genetic resources is very large: 24 species are cultivated, 38 edible species are congeneric with cultivated crops and at least 10 other species bear inedible fruit but are related to cultivated crops. We conclude that the Peninsular Malaysian rain forest is exceedingly rich in wild fruit trees, that these normally live at low densities, and that their principal economic value is as genetic resources. 相似文献
17.
林木基因克隆研究进展 总被引:1,自引:0,他引:1
林木种质资源丰富, 种质间遗传差异大, 控制林木重要性状的基因克隆及转化对培育优良林木新品种具有很强的实用价值, 但许多具有潜在应用价值的林木基因未得到充分发掘和有效分离。近年来, 随着各种不同林木cDNA文库的建立, 大规模随机EST测序技术的运用以及克隆技术的不断完善, 特别是毛果杨(Populus trichocarpa)基因组测序计划的完成, 大量与林木重要性状相关的基因被分离和鉴定。这些重要基因的获得为利用转基因技术培育高产、优质、抗逆、抗病虫害的林木新品种奠定了一定的基础。该文综述了20多年来国内外林木基因克隆的研究进展, 对基因克隆及其应用过程中亟待解决的问题进行了讨论, 并对其发展趋势进行展望。 相似文献
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The citrus fruit proteome: insights into citrus fruit metabolism 总被引:1,自引:0,他引:1
Fruit development and ripening are key processes in the production of the phytonutrients that are essential for a balanced diet and for disease prevention. The pathways involved in these processes are unique to plants and vary between species. Climacteric fruit ripening, especially in tomato, has been extensively studied; yet, ripening of non-climacteric fruit is poorly understood. Although the different species share common pathways; developmental programs, physiological, anatomical, biochemical composition and structural differences must contribute to the operation of unique pathways, genes and proteins. Citrus has a non-climacteric fruit ripening behavior and has a unique anatomical fruit structure. For the last few years a citrus genome-wide ESTs project has been initiated and consists of 222,911 clones corresponding to 19,854 contigs and 37,138 singletons. Taking advantage of the citrus database we analyzed the citrus proteome. Using LC-MS/MS we analyzed soluble and enriched membrane fractions of mature citrus fruit to identify the proteome of fruit juice cells. We have identified ca. 1,400 proteins from these fractions by searching NCBI-nr (green plants) and citrus ESTs databases, classified these proteins according to their putative function and assigned function according to known biosynthetic pathways. 相似文献
20.
We investigated distribution and abundance patterns of a recently arrived species in the oases of southern Tunisia: the Common Blackbird Turdus merula . In this system, we expected that the vegetation structure and geographical locations of oases would have played an important part in shaping the patterns of oasis occupancy and local abundance. Using data collected at 53 oases during two breeding seasons, we found that Blackbird occurrence in a given oasis depended mainly on its presence at neighbouring oases. However, vegetation structure did not prove to be a relevant predictor of Blackbird occurrence. Within occupied oases, local abundance was associated with vegetation structure, namely with the diversity and abundance of the two lowest vegetation layers: fruit trees and herbaceous plants. The presence of Blackbirds at neighbouring oases was not found to account for local abundance. Overall, our results suggest that the distribution and abundance of this newly colonizing species in the southern Tunisian oasis system are influenced by processes acting at two different spatial scales. Landscape-scale processes (i.e. dispersal and colonization from nearby occupied oases) are likely to play an important role in shaping the pattern of oasis occupancy, whereas local-scale factors seem to be more relevant in determining the abundance of locally established populations. 相似文献