Culture Of Population Research Articles

Analysis of the Conservation Status, Genetic Diversity and Population Structure of Endangered Ostrya rehderiana Resources Using SSR Markers

Climate change and anthropogenic habitat destruction have led to the extinction of many species. Ostrya rehderiana (Betulaceae) is a typical rare and endangered species, and only five wild individuals have survived. In the 1980s, the offspring of the five wild trees were planted for ex situ conservation and have grown into stable cultivated populations. To protect O. rehderiana resources, the genetic diversity and genetic structure of this species were analysed using SSR markers. A total of 167 alleles were detected among 116 individuals from the only wild population and five cultivated populations at 12 SSR loci. The genetic diversity level of O. rehderiana was He = 0.88. Genetic differentiations occurred among populations (Fst = 0.17), which was also validated via an analysis of molecular variance (AMOVA). The cultivated populations TM1, TM2 and WC showed considerable genetic differences from the wild population WP based on Bayesian clustering analysis, phylogenetic tree reconstruction and principal coordinate analysis (PCoA). The cultivated populations had more genetic diversity than the wild one. It is speculated that novel alleles may have emerged out of natural processes of evolution and adaptation. The cultivated population QY with the most unique alleles has begun to propagate seedlings naturally, and the small population size and geographical isolation may negatively influence the founding of this population. To weaken the effects of bottlenecks and genetic drift, anthropogenic gene flow among populations is necessary. In addition to the wild population, the cultivated population QY and six individuals from populations QY and WC were also found to be important for the conservation of O. rehderiana. The results of this study may guide the development of conservation policies for endangered O. rehderiana.

Comparative study of representatives of different populations of <i>Sedum roseum</i> (L.) Scop growing in conditions of field crop rotation

Aim. Comparative study of the source material of four populations of Sedum roseum (L.) Scop. belonging to different ecological and geographical zones of origin and assessment of their suitability for cultivation in the conditions of the non‐chernozem zone of the Russian Federation.Materials and methods. The following populations were studied: the cultivated population of VILAR (Altai, 1980), the cultivated population of the Botanical Garden of Pitirim Sorokin Syktyvkar State University (Syktyvkar, Komi Republic), an introduced population from Kirovsk, N. A. Avrorin Polar‐Alpine Botanical Garden‐Institute and a cultivated population of Innsbruck Botanical Garden, Austria.Results. Morphological description of the samples was carried out and the productivity of raw materials and seeds and the main biological and karyological features of the populations studied were determined. The results of made it possible to identify Rhodiola populations characterized by high winter hardiness (A and D) and low winter hardiness (B and C). A high productivity of roots and rhizomes in the fourth year of life in populations C and A (30–31 g) was established, and in terms of the content of active substances (phenylpropanoids) in population B (Komi) – 5.4%. The numbers of chromosomes (2n=22) were determined and their morphometric analysis was carried out and formulas of karyotypes of the Rhodiola populations studied were compiled. Chromosomal analysis using C/DAPI‐differential staining showed that no chromosomal abnormalities were detected in the karyotypes, which indicates their stability.Conclusion. Morphological variability indicates the ecological plasticity of the populations studied, which indicates the prospects for their field cultivation.

Comparative study of multiple approaches for identifying cultivable microalgae population diversity from freshwater samples.

The vast diversity of microalgae imposes the challenge of identifying them through the most common and economical identification method, morphological identification, or through using the more recent molecular-level identification tools. Here we report an approach combining enrichment and metagenomic molecular techniques to enhance microalgae identification and identify microalgae diversity from environmental water samples. From this perspective, we aimed to identify the most suitable culturing media and molecular approach (using different primer sets and reference databases) for detecting microalgae diversity. Using this approach, we have analyzed three water samples collected from the River Nile on several enrichment media. A total of 37 microalgae were identified morphologically to the genus level. While sequencing the three-primer sets (16S rRNA V1-V3 and V4-V5 and 18S rRNA V4 region) and aligning them to three reference databases (GG, SILVA, and PR2), a total of 87 microalgae were identified to the genus level. The highest eukaryotic microalgae diversity was identified using the 18S rRNA V4 region and alignment to the SILVA database (43 genera). The two 16S rRNA regions sequenced added to the eukaryotic microalgae identification, 26 eukaryotic microalgae. Cyanobacteria were identified through the two sequenced 16S rRNA regions. Alignment to the SILVA database served to identify 14 cyanobacteria to the genera level, followed by Greengenes, 11 cyanobacteria genera. Our multiple-media, primer, and reference database approach revealed a high microalgae diversity that would have been overlooked if a single approach had been used over the other.

Genetic Structure and Diversity in Wild and Cultivated Populations of the Mangrove Oyster Crassostrea gasar from Southern Brazil.

The mangrove oyster (Crassostrea gasar) is Brazil's second most cultured species and presents a high potential for aquaculture. However, artificial selection in a highly fecund species and significant variance in reproductive success can result in the loss of genetic diversity and increases the inbreedingrate, especially in cultivated populations. In this study, we investigated the genetic structure and diversity of C. gasar in wild and cultivated populations using 14 microsatellites. Spatial genetic comparisons revealed the existence of two main genetic groups of C. gasar, one comprising the population in cultivation and the other formed by wild populations along the southern and southeastern Braziliancoasts. Although no common genetic structure exists among wild populations, it is possible to observe a distribution gradient based on discriminant analysis of principal components consistent with their geographic distribution. However, it is insufficient to differentiate them genetically. Despite artificial reproduction, thegenetic diversity values of the cultivated population remained relatively high and did not show areduction. Therefore, monitoring the cultivated population and establishing reference values for genetic diversity will allow the adoption of strategies both for the viability of the cultivated population and the management of wild populations.

SSR and 18S rDNA based molecular profiling of Neopyropia yezoensis (Rhodophyta) in China: insight into genetic impact of laver aquaculture on wild resource

Neopyropia yezoensis is a typical intertidal seaweed and an indispensable species for conservation of seaweed resources. As one of the most important marine vegetables, the cultivation area of N. yezoensis has been largely increasing in the past decade and ranked the second highest among all the farmed seaweeds in China. It remains unknown whether large-scale cultivation of N. yezoensis has a genetic impact on wild populations. In this study, SSR markers and 18S rDNA were applied for diversity and genetic structure analysis of 22 N. yezoensis populations from North China. Twenty-two haplotypes were generated from 352 18S rDNA sequences and only three haplotypes were shared by both cultivated and wild populations. Based on 11 polymorphic SSR markers developed, the average polymorphism of the cultivated N. yezoensis populations was higher than that of the wild populations, with the percentage of polymorphic loci being 90.91% in most cultivated populations. The cultivated populations were clustered separately from the wild ones based on the population phylogenetic tree. This indicates that cultivated N. yezoensis populations are diverse and divergent from wild populations in China. However, there were cultivated individuals mixed with the wild ones based on the individual phylogenetic tree and STRUCTURE analysis. The genetic differentiation between cultivated and wild populations decreased with increasing cultivation time, suggesting a possible long-term and slow process of genetic introgression between cultivated N. yezoensis and the wild resource. The wild populations were grouped into two distinct clades by SSRs, with one distributed around the intersection between the Yellow Sea and the Bohai Sea, where the populations were characterized by a specific 18S rDNA haplotype. These findings provide useful insights into germplasm conservation, genetic breeding and improvement of N. yezoensis farming practices.

The genomics of linkage drag in inbred lines of sunflower

Crop wild relatives represent valuable sources of alleles for crop improvement, including adaptation to climate change and emerging diseases. However, introgressions from wild relatives might have deleterious effects on desirable traits, including yield, due to linkage drag. Here, we analyzed the genomic and phenotypic impacts of wild introgressions in inbred lines of cultivated sunflower to estimate the impacts of linkage drag. First, we generated reference sequences for seven cultivated and one wild sunflower genotype, as well as improved assemblies for two additional cultivars. Next, relying on previously generated sequences from wild donor species, we identified introgressions in the cultivated reference sequences, as well as the sequence and structural variants they contain. We then used a ridge-regression best linear unbiased prediction (BLUP) model to test the effects of the introgressions on phenotypic traits in the cultivated sunflower association mapping population. We found that introgression has introduced substantial sequence and structural variation into the cultivated sunflower gene pool, including >3,000 new genes. While introgressions reduced genetic load at protein-coding sequences, they mostly had negative impacts on yield and quality traits. Introgressions found at high frequency in the cultivated gene pool had larger effects than low-frequency introgressions, suggesting that the former likely were targeted by artificial selection. Also, introgressions from more distantly related species were more likely to be maladaptive than those from the wild progenitor of cultivated sunflower. Thus, breeding efforts should focus, as far as possible, on closely related and fully compatible wild relatives.

Looking for non-hermaphrodite cacti: multidisciplinary studies in Gymnocalycium bruchii endemic to central Argentina.

Through a multidisciplinary study we found that Gymnocalycium bruchii, an endemic cactus from central Argentina, acts as a dioecious species, which is the first record in this genus. Cactaceae species are typically hermaphroditic; however, about 2% have other different reproductive systems. These non-hermaphroditic species may develop sexual dimorphism in flowers or other reproductive, vegetative or ecological traits, besides a specific breeding system and floral ontogeny. Therefore, multidisciplinary research is necessary to fully understand reproduction in those species. For this purpose, we studied Gymnocalicium bruchii, a globose cactus endemic to central Argentina that is presumably dioecious or gynodioecious. We made observations in two natural and two cultivated populations. We made morphological observations of plants and flowers, and performed quantitative analyses to determine the sex ratio, size of plants and flowers, flower production, fruiting, among other variables. We performed hand-pollination, self-fertilization and free-pollination tests to determine the breeding system. Finally, we studied the anatomy and ontogeny of the reproductive organs using permanent histological slides of flower morphs at different stages. Our results confirm that Gymnocalicium bruchii is a dioecious species. Female flowers have atrophied anthers and a functional gynoecium that produces fruits and seeds. Male flowers are bigger and have a functional androecium but a sterile gynoecium. In the cultivated population, the sex ratio was 1/1, whereas the number of male individuals was higher in both natural populations. Pollination tests corroborated dioecy. Ontogenetic studies revealed that in female flowers the anthers collapse before microspore maturation, while in male flowers the gynoecium shows normal development of the ovary, style, stigma, and ovules; however, the latter are never fertilized.

Nuclear DNA content and comparative FISH mapping of the 5s and 45s rDNA in wild and cultivated populations of Physalis peruviana L.

Physalis peruviana L. often known as goldenberry, has increased its commercial growth in the international market in recent years due to its nutritional value and antioxidant potential. This situation has enabled countries such as Peru to increase their production in order to meet the global demand. However, investigations about the genetic diversity of cultivated and wild populations of goldenberry are still in their early stages. FISH mapping of 5s and 45s rDNA loci and flow cytometry estimation of nuclear DNA content were used to assess genetic differences between wild and cultivated goldenberry populations from Ayacucho and Cajamarca. The majority of metaphases had six 5s rDNA sites for all populations and two and four 45s rDNA sites for the cultivated and wild populations, respectively. We were able to characterize nine different types of chromosomes based on their morphology, fluorescence, rDNA location, and conservation across populations by analyzing the chromosomes that contained rDNA. Furthermore, cultivated populations had more nuclear DNA (13.262±0.087 pg) than wild populations (12.955±0.086 pg). The results show genetic differences between wild and cultivated populations of goldenberry at molecular cytogenetic level as well as in genome size. These findings establish a precedent for future cytogenetic and genomic studies in goldenberry populations, enabling future breeding programs.

Análisis y caracterización de poblaciones bacterianas solubilizadoras de P en un ensayo de larga duración con diferentes secuencias de cultivo

It is well known that different soil use and management systems affect the abundance, activity and composition of the soil microbial community. In this work, the behavior of cultivable bacterial populations and, in particular, P (PSB) solubilizing bacteria in soil samples from a long-term trial with different culture sequences was studied. The results obtained show that the clearing and subsequent agricultural use after 11 years generated a decrease in the population of cultivable bacteria in general, and of P-solubilizing bacteria in particular, with respect to the pristine soil. Isolates with high P solubilization efficiency were obtained from the soils from the different rotations. These efficient isolates were taxonomically classified by 16S RNA analysis as belonging to the genera Bacillus, Paenibacillus, Pseudomonas and Xanthomonas. In particular, the characterization of the culture supernatants of the isolates Pseudomonas koreensis and Paenibacillus pabuli showed they are producers of organic acids. The combined inoculation tests of these two strains on maize plants in a culture chamber revealed a synergistic effect on the growth promotion of this species. The results presented here suggest that although PSB populations are more numerous in pristine soils, certain long-term crop rotations favor the increase of more efficient solubilizing bacteria, an aspect that should be considered when designing future search strategies for potential bioinoculants.

Eco-friendly bio-encapsulation from sodium alginate-trehalose-kaolin and its performance evaluation in improving plant growth under salt or/and drought conditions

Plant growth-promoting bacterium plays a significant role in improving plant tolerance to abiotic stresses. However, there are low survival and poor effect in field application, especially in unfavorable environments. Our previous study suggested that encapsulation of Bacillus pumilus G5 from polyvinyl alcohol‑sodium alginate could improve plant growth and soil fertility under drought and salt soil conditions. However, in the G5 microbeads, the polyvinyl alcohol could not be degraded after entering the soil, and the loss of viable bacteria was severe during the drying process. Achieving a more eco-friendly and efficient formulation based on biodegradable polymers can have significant effects on increasing the quantity and quality of agricultural products. Herein, G5 has immobilized in the composite wall of sodium alginate-trehalose-kaolin microbeads and then evaluated the performance, and applied on the Pharbitis nil under salt or/and drought stress by pot experiment. A 2 % sodium alginate, 1 % trehalose, and 1 % kaolin formulation for the coating films resulted in optimal G5 microbeads embedding efficiency, viable bacteria, degradation rate, and sustained release. Also, the G5 microbeads exhibited longer storage life than that of the G5 suspension. Scanning electron microscopy revealed that the G5 microcapsules had a near-spherical structure with a particle size of around 1000 μm forming a continuous dense composite wall membrane with obvious protrusions and folds on the surface, which facilitated the release of the G5 strain. The interior of the G5 capsule was rough and suitable for bacterial attachment. Infrared spectroscopy showed that the G5 microcapsules are a simple physical mixture with no chemical reaction between the excipients, making the G5 microcapsules chemically stable. The inclusion of the G5 microcapsules considerably induced Pharbitis nil seedlings growth and biomass under drought and/or salt stress. In the rhizosphere soil of Pharbitis nil, the G5 microcapsules increased the total cultivable bacteria population, the activities of invertase, urease, phosphatase, and catalase, and the contents of available nitrogen and available phosphorus. We concluded that a suitable formulation by bio-encapsulation with eco-friendly excipients for alleviating drought and/or salt stress in plants will be advantageous in sustainable agriculture.

Spatio-temporal variation on land use and land cover and its drivers under watershed management activities in Becho, Central Highlands of Ethiopia

Abstract The study sought to understand the spatio-temporal variation of land use and land cover (LULC) and its drivers under watershed management activities in Becho district, in Ethiopia’s Central Highlands. To gain a better comprehension of the subject, two micro watersheds were chosen to test the effectiveness of watershed management activities (treated-Shankur Tareqo and untreated-Mende Tufessa). LULC changes were detected using aerial photography (1973), and satellite images from Landsat 5 TM (1990), Spot 5 (2005), and Landsat 8 OLI (2021) obtained from the Ethiopian Geospatial Information Institute and the United States Geological Survey. In addition, key informant interviews (KII) and focus group discussions (FGD) were used to elicit LULC drivers. Between 1973 and 2021, the total area of woodland, and cultivated and rural settlement land LULC classes in the treated micro-watershed decreased by 24.65% (171.9 ha) and 7.34% (759 ha), respectively. Though, grassland, forestland, and barrenland increased by 30.83% (179.52 ha), 1% (3 ha), and 183.14% (755.28 ha), respectively. The overall area of LULC class for woodland, grassland, forestland, and cultivated and rural settlement decreased by 50.36% (316.16 ha), 41.23% (196.46 ha), 2.43% (11.85 ha), and 1.35% (138.6 ha), respectively, in the untreated micro-watershed, while barrenland increased by 175.86% (666.55 ha). According to KII and FGD, the drivers of LULC changes were identified as the expansion of cultivated land, population pressure, and government policy. According to the findings, local-scale watershed management activities was not as effective as expected. As a result, in order to achieve the desired outcome, the concerned stakeholders should reconsider how watershed management activities is undertaken.

Influence of vintage, geographical location and agricultural management on yeast populations in Galician grape musts (NW Spain)

The influence of vintage, geographical location and farming system on yeast populations was evaluated in grape musts from Galicia (NW Spain) in three consecutive years. Grape samples were taken in organic and conventional vineyards from four Denominations of Origin (DOs) during the 2013, 2014 and 2015 vintages. Cultivable yeast populations were characterised at the quantitative and qualitative level. The general results show the existence of significant differences for yeast counts in musts among vintages and DOs, but not between farming systems. Given the geographical location of the grapes, the influence of vintage was significant in all DOs; however, the farming system only had a significant impact on viable yeasts in Rías Baixas, although the number of yeasts tended to be higher in organic samples than in conventional ones in most cases. Species richness was location dependent, with Rías Baixas and Ribeira Sacra showing the highest values. In addition, the type of yeasts varied between Denominations of Origin. From a total of 39 different yeast species identified, Metschnikowia spp., Hanseniaspora uvarum and Aureobasidium spp. were the prevailing species. These major yeasts were found to be widely distributed. However, species such as Issatchenkia terricola, Starmerella bacillaris and different species of Candida, Pichia and Zygosaccharomyces genera were mainly found in Rías Baixas and Ribeira Sacra DOs. In contrast, Lachancea thermotolerans was isolated in Monterrei and Ribeiro DOs only. Accordingly, the ANOSIM and PERMANOVA analyses evidenced significant differences in species richness among different DOs and, to a lesser extent, among vintages, but not between farming systems.

The rapid appearance of homostyly in a cultivated distylous population of Primula forbesii.

Evolutionary breakdown from rigorous outbreeding to self-fertilization frequently occurs in angiosperms. Since the pollinators are not necessary, self-compatible populations often reduce investment in floral display characteristics and pollination reward. Primula forbesii is a biennial herb with distribution restricted to southwest China; it was initially a self-incompatible distylous species, but after 20 years of artificial domestication, homostyly appeared. This change in style provides an ideal material to explore the time required for plant mating systems to adapt to new environmental changes and test whether flower attraction has reduced following transitions to selfing. We did a survey in wild populations of P. forbesii where its seeds were originally collected 20 years ago and recorded the floral morph frequencies and morphologies. The floral morphologies, self-incompatibility, floral scent, and pollinator visitation between distyly and homostyly were compared in greenhouse. Floral morph frequencies of wild populations did not change, while the cultivated population was inclined to L-morph and produced homostyly. Evidence from stigma papillae and pollen size supports the hypothesis that the homostyly possibly originated from mutations of large effect genes in distylous linkage region. Transitions to self-compatible homostyly are accompanied by smaller corolla size, lower amounts of terpenoids, especially linalool and higher amounts of fatty acid derivatives. The main pollinators in the greenhouse were short-tongued Apis cerana. However, homostyly had reduced visiting frequency. The mating system of P. forbesii changed rapidly in just about 20 years of domestication, and our findings confirm the hypothesis that the transition to selfing is accompanied by decreased flower attraction.

Geographic factors and climatic fluctuation drive the genetic structure and demographic history of Cycas taiwaniana (Cycadaceae), an endemic endangered species to Hainan Island in China.

Hainan Island had experienced several cold-warm and dry-humid fluctuations since the Late Pleistocene period, resulting in separating and connecting from the mainland several times with the cyclic rise and fall of sea level. The fluctuations can change the biota and ecological environment in the island. Cycas taiwaniana Carruthers is endemic to Hainan Island and is classified as endangered by the International Union for Conservation of Nature (IUCN). To comprehensively understand the genetic dynamics of C.taiwaniana, we sampled 12 wild populations in Hainan Island and one cultivated population in Fujian province, and analyzed the genetic diversity, genetic structure, and demographic history based on the molecular data. Results revealed that C.taiwaniana had relatively low genetic diversity and high genetic differentiation. Haplotypes of C.taiwaniana diversified during the Pleistocene based on the chloroplast DNA (cpDNA) and the concatenated nuclear DNA (nDNA) data. Genetic cluster analyses based on the microsatellite (SSR) data showed that the 12 wild populations were separated into three clusters which could be three evolutionary significant units (ESUs), indicating three basic units of protection were identified. Moreover, we also confirmed the cultivated population FJ derived from the DLS1-GSL clade. Demographic inference from different data was discordant, but overall, it uncovered that C.taiwaniana had experienced population contraction events twice during the Pleistocene and Holocene, and then expanded recently. Our study elucidated the population genetic characteristics of C.taiwaniana, and guided us to develop targeted conservation and management strategies for this endangered species.

Identification of stable QTL controlling multiple yield components in a durum × cultivated emmer wheat population under field and greenhouse conditions.

Crop yield gains are needed to keep pace with a growing global population and decreasing resources to produce food. Cultivated emmer wheat is a progenitor of durum wheat and a useful source of genetic variation for trait improvement in durum. Here, we evaluated a recombinant inbred line population derived from a cross between the North Dakota durum wheat variety Divide and the cultivated emmer wheat accession PI 272527 consisting of 219 lines. The population was evaluated in 3 field environments and 2 greenhouse experiments to identify quantitative trait locus associated with 11 yield-related traits that were expressed in a consistent manner over multiple environments. We identified 27 quantitative trait locus expressed in at least 2 field environments, 17 of which were also expressed under greenhouse conditions. Seven quantitative trait locus regions on chromosomes 1B, 2A, 2B, 3A, 3B, 6A, and 7B had pleiotropic effects on multiple yield-related traits. The previously cloned genes Q and FT-B1, which are known to be associated with development and morphology, were found to consistently be associated with multiple traits across environments. PI 272527 contributed beneficial alleles for quantitative trait locus associated with multiple traits, especially for seed morphology quantitative trait locus on chromosomes 1B, 2B, and 6A. Three recombinant inbred lines with increased grain size and weight compared to Divide were identified and demonstrated the potential for improvement of durum wheat through deployment of beneficial alleles from the cultivated emmer parent. The findings from this study provide knowledge regarding stable and robust quantitative trait locus that breeders can use for improving yield in durum wheat.

The growing water crisis in Central Asia and the driving forces behind it

Central Asia (CA) is one of the most severe water crisis areas on earth, which has seriously limited the achievement of sustainable development goals (SDGs) in the region. However, a multi-perspective analysis on the process and driving factors of the water crisis in CA has not been conducted. Therefore, we assess the water crisis from multiple perspectives using the water stress index (WSI), safe drinking water and water pollution indicators, and quantitatively analyze the impact of climate change, population growth, poverty, urbanization and transboundary river management on the water crisis. Results show that the water crisis in CA is intensifying. Uzbekistan and Turkmenistan belong to the “severe water stress” category, and the WSIs are increasing in both countries. Tajikistan is classified as “high water stress”. Kyrgyzstan and Kazakhstan both exhibit “moderate water stress”. Moreover, the proportion of the rural population with access to safe drinking water is significantly lower than that of the urban population in all the CA countries. The impact of human activities on water crisis in CA is more significant than that of climatic factors. Both cultivated land area and population are significant factors affecting the water crisis in CA (p < 0.05), with the regression coefficients of 0.62 and 1.62, respectively. Our research provides an essential reference for the sustainable management of water resources and warns that the water security situation in CA will worsen if no effective action is taken.

Domestication Syndrome in Dacryodes edulis (Burseraceae): Comparison of Morphological and Biochemical Traits between Wild and Cultivated Populations.

For millennia, people have harvested fruits from the wild for their alimentation. Gradually, they have started selecting wild individuals presenting traits of interest, protecting and cultivating them. This was the starting point of their domestication. The passage from a wild to a cultivated status is accompanied by a modification of a number of morphological and genetic traits, commonly known as the domestication syndrome. We studied the domestication syndrome in Dacryodes edulis (G.Don) H.J.Lam (known as ‘African plum’ or ‘safoutier/prunier’), a socio-economically important indigenous fruit tree species in West and Central Africa. We compared wild and cultivated individuals for their sex distribution; flower, fruit and seed morphometric characteristics; seed germination temporal dynamic and fruit lipid composition. We found a higher percentage of male and male-hermaphrodite sexual types in wild populations than in cultivated ones; a lower fruit and seed mass in wild individuals; and similar mean time of germination, oil content and fatty acid composition between wild and cultivated individuals. Our results are interpreted in light of the presence of a domestication syndrome in D. edulis.

When half is more than the whole: Wheat domestication syndrome reconsidered.

Two opposing models currently dominate Near Eastern plant domestication research. The core area-one event model depicts a knowledge-based, conscious, geographically centered, rapid single-event domestication, while the protracted-autonomous model emphasizes a noncentered, millennia-long process based on unconscious dynamics. The latter model relies, in part, on quantitative depictions of diachronic changes (in archaeological remains) in proportions of spikelet shattering to nonshattering, towards full dominance of the nonshattering (domesticated) phenotypes in cultivated cereal populations. Recent wild wheat genome assembly suggests that shattering and nonshattering spikelets may originate from the same (individual) genotype. Therefore, their proportions among archaeobotanical assemblages cannot reliably describe the presumed protracted-selection dynamics underlying wheat domestication. This calls for a reappraisal of the "domestication syndrome" concept associated with cereal domestication.

Predictive biophysical models of bivalve larvae dispersal in Scotland

In Scotland, bivalves are widely distributed. However, their larvae dispersion is still largely unknown and difficult to assess in situ. And, while Mytilus spp. dominate shellfish production, it is mostly dependent on natural spat recruitment from wild populations. Understanding the larval distribution pattern would safeguard natural resources while also ensuring sustainable farming practises. The feasibility of a model that simulates biophysical interactions between larval behaviour and ocean motions was investigated. We employed an unstructured tri-dimensional hydrodynamic model (finite volume coastal ocean model) to drive a particle tracking model, where prediction of larval movement and dispersal at defined locations might aid in population monitoring and spat recruitment. Our findings reveal a strong link between larval distribution and meteorological factors such as wind forces and currents velocity. The model, also, depicts a fast and considerable larval movement, resulting in a substantial mix of plankton and bivalve larvae, forming a large connection between the southern and northern regions of Scotland’s West coast. This enables us to forecast the breeding grounds of any area of interest, potentially charting connectivity between cultivated and wild populations. These results have significant implications for the dynamics of ecologically and economically important species, such as population growth and loss, harvesting and agricultural management in the context of climate change, and sustainable shellfish fisheries management. Furthermore, the observations on Scottish water flow suggest that tracking particles with similar behaviour to bivalve larvae, such as other pelagic larval stages of keystone species and potential pathogens such as sea lice, may have policy and farming implications, as well as disease control amid global warming issues.

Does Economic Growth Lead to an Increase in Cultivated Land Pressure? Evidence from China

With economic growth, people’s living standards improve, and more cultivated land is needed to meet food demand. Meanwhile, the economic growth and urban expansion in China since 1978 has led to the loss of considerable amounts of cultivated land. Thus, the contradiction between “economic growth” and “food security” becomes increasingly prominent. Studying the impact of economic growth on cultivated land population support pressure is the basis for easing this problem. This study uses the cultivated land pressure index to represent cultivated land population support pressure, and explores the relationship between economic growth and cultivated land pressure based on the panel data of 31 provinces in China from 2000 to 2017. The feasibility generalized least squares estimation and the fixed effect model based on Driscoll and Kraay standard errors are used. The results show that: (1) the impact of economic growth on cultivated land pressure is an N-shaped or U-shaped curve; and (2) there are regional differences in the impact of economic growth on cultivated land pressure. The cultivated land pressure in economically developed regions and main grain production regions responds slowly to the impact of economic growth. Therefore, some policy recommendations are put forward, such as paying attention to cultivated land protection and controlling disorderly urban expansion.