Density Of Seeds Research Articles

Assessing the status of soil seed bank in Parthenium hysterophorus invaded land use types and its social aspects in Lower Hare Watershed, Southern Ethiopia

In Ethiopia, Parthenium hysterophorus (P. hystrophorus) is an invasive alien plant affecting various ecosystems. P. hysterophorus displaced native plant species and caused a serious threat to biodiversity. This study aimed to assess soil seed bank of P. hysterophorus under major land use types and assess community perception towards the effects of P. hysterophorus on social aspects in lower Hare watershed. For this study, 210 soil samples were collected from fifteen transect lines in grassland, cropland, and forest land use types. Statistical analysis using three ways factorial ANOVA was used to analyze the difference in density of P. hysterophorus among various land uses soil depths, and sites (P < 0.05). For the perception of local communities regarding the effects of P. hysterophorus, a total of 117 respondents were used and semi-structured and close-ended questionnaires for data collection. It found that all factors: land use, site, and soil depth significantly affected the soil seed bank density in the lower Hare watershed (P < 0.05). Results indicated that mean density of seeds were the highest in croplands of other land use types. Meanwhile, the highest mean density of seeds was identified in 0-10 cm soil depth, but the lowest mean density of seeds was identified in 10-15 cm soil depth. The highest seeds were identified at Chano Cheliba, but the density of seeds the lowest in density at Kola Shera. 38.5% of households in Kola Shera, and 21.4% in Kola Cheliba, but 8.5% in Kola Doriga said that it had effects on ecosystem services such as crop yield and livestock production. There should be a need for increased awareness about the density of P. hysterophorus in various land uses and its impacts on native plant species. Seeking possible solutions such as biological and mechanical control methods are among the local people, researchers, and extension workers can use for the management of its invasion, and appropriate control measures can be designed to combat its further invasion and impacts on different land uses of the region.

Woody species’ carbon sequestration and soil seed bank conservation potentials of traditional rangeland management strategies in Western Guji, Southern Ethiopia

Rangelands are important for mitigating climate change and rehabilitating land by storing carbon from woody plants and seeds in the soil. However, there is a lack of empirical data on how traditional rangeland management practices (such as enclosure, communal grazing and prescribed fire) affect the carbon storage of woody species and the conservation potential of soil seed banks. This study evaluates the carbon sequestration and soil seed bank conservation potential of traditional rangeland management practices in the Western Guji zone, Ethiopia. A total of 32 sample plots were established using systematic random sampling, with 12 in each management practice, to measure woody biomass and estimate carbon stock using a nondestructive method. Additionally, 72 soil samples were collected for soil seed bank analysis, with 24 samples taken from each type of rangeland management practice. The study found that enclosures had the highest amount of carbon stocks 63.1 tons per hectare (t ha−1), with a corresponding carbon dioxide equivalent (CO2e) sequestration of 231.58 t ha-1, followed by communal grazing areas that stored 27.05 t ha−1 of carbon with a CO2e sequestration of 99.27 t ha−1. Prescribed fire had the lowest carbon stocks at 19.39 t ha−1, with a CO2e sequestration of 71.16 t ha−1. The study also found that different traditional rangeland management practices significantly influenced the diversity, richness, and density of woody species in soil seed banks. The highest Shannon diversity was recorded in enclosures (3.56 ± 0.09), followed by communal grazing (2.87 ± 0.14) and prescribed fire (1.27 ± 0.08). As a result, enclosure promotes the storage of carbon in woody plants and increases the diversity, density, and richness of woody species seeds in the soil, while prescribed fire reduces it. Therefore, it recommend for pastoralists to expand the use of enclosures as it improves the potential for conserving carbon stocks and soil seed banks of woody species.

Pollinator planting establishment and bee visitation are influenced by seeding rate and post‐seeding management

Perennial wildflower plantings are commonly used to support pollinators and other beneficial insects, but their establishment can be costly, and few studies have directly compared the effectiveness of different management strategies for wildflower establishment. To determine the relative importance of pre‐seeding weed control, seed density, and post‐seeding management on seed mix establishment, we developed a multifactorial field experiment in a grass‐dominated weed community. Pre‐seeding management treatments (mowing, herbicide, or soybean cover crops) did not affect the stem density of sown plants, or the percent of ground covered by sown plants. However, the percent of ground covered by weeds was significantly influenced by pre‐seeding treatments, with infrequent mowing resulting in significantly less weedy ground cover than the herbicide or soybean pre‐seeding treatments. Plots with a higher seeding rate had a significantly greater density of sown wildflower species and a higher percent cover of these species after 3 years. Plots that received no post‐seeding management had higher stem density, a greater percent ground cover of sown forbs, and higher species richness compared to those that were intensively managed (mow or mow + herbicide). The total number of bee visits (honey bees, bumble bees, and other wild bees) increased with higher forb species richness, higher ground cover of sown forbs, and higher sown species richness. Doubling the density of seeds resulted in a 24.3% increase in the number of wild bees observed. When establishing wildflower habitat for pollinators, investment in ground preparation and seeding density has the greatest impact on sown species establishment.

The effects of native seed mix composition and sowing density on plant community reassembly in wetlands

AbstractSeed‐based restoration of wetlands is often necessary to improve important ecosystem functions (e.g., invasion resistance and habitat provisioning) and meet society's need for wetland ecosystem services such as supporting recreational activities and improving water quality. However, persistent questions remain about the composition and sowing density of seed mixes needed to restore robust native wetland plant communities. In Great Salt Lake wetlands (Utah, USA), the revegetation of native species is crucial to recovering critical habitat and preventing reinvasion of the invasive, non‐native grass Phragmites australis and other invasive species (e.g., Typha spp.). In greenhouse and field experiments, we investigated the effects of seed mix composition and sowing density on plant community reassembly. We predicted that seed mixes containing native forb species with resource‐preempting traits (e.g., rapid seedling emergence and high aboveground growth rate) and high sowing densities (>5500 pure live seed m−2), would increase native plant light acquisition and establishment, thereby limiting invasive species. To our surprise, the effect of seed mix composition on native plant performance (cover and biomass) varied among the experiments, with distinct differences between plant functional groups arising. Native forb species had the highest performance in the greenhouse, but native grasses performed better in the field. Although multiple seed mix compositions show promise for establishing high native cover and biomass, these mixes may not always suppress invasive species. Interestingly, seed mix composition most often affected plant performance independent of sowing density. However, in one greenhouse experiment, we found that only slow‐growing mixes required a high sowing density to maximize native cover, an indication that the ideal sowing density may depend on the seed mix composition. Our research also supports the idea that in addition to reducing propagules of invasive species via appropriate management strategies, the application of higher sowing densities (>5500 pure live seed m−2) may lead to more favorable outcomes when a high density of invasive plant seeds remains or stressful field conditions are present. This research contributes to knowledge of plant community reestablishment in wetlands and demonstrates how seed‐based restoration strategies can catalyze native species revegetation and, in some situations, reduce the cover of invasive species.

What Is in the Bank? Assessing Persistent Soil Seed Bank Density of Sclerocactus wrightiae (Cactaceae)

Wright fishhook cactus is a small globose cactus endemic to an area of 280,000 ha in south-central Utah and was listed as endangered in October of 1979 by the U.S. Fish and Wildlife Service (USFWS). There is a general paucity of information about this species, and no published data on the seed bank for any species in the genus. Our objective with this study was to provide insight into the established seed bank density for this species. We processed 500 soil samples from various locations near individual cacti and potential neighboring nurse plants. We found that the species had a detectable seed bank of a size similar to other members of the Cactaceae family. Seed bank densities were the highest immediately adjacent to, and downslope from, parent plants. Our data indicate that areas within 20 cm of seed-producing cacti contain by far the greatest density of seeds. These areas should be given special consideration in future management plans for this species.

Core-shells particles grown in a tubular reactor: Influence of the seeds nature and MPCVD conditions on boron-doped diamond crystalline quality

A trend in the synthesis of Boron Doped Diamond (BDD) materials resides in increasing surface areas to exalt reactivity at the BDD/electrolyte interface. This can be achieved either by surface structuration of BDD films or conformal growth on 3D substrates. Another strategy considers isolated BDD particles, mainly obtained by milling of BDD layers that can be further deposited on surfaces or embedded in a conductive matrix. Here, we propose an alternative method to obtain boron-doped diamond particles using a core-shell approach, which consists in growing diamond coatings on spherical silica templates seeded with nanodiamonds. We investigated the effects of the nature and the density of diamond seeds as well as growth parameters on the crystalline quality of the coatings. The microstructure and the boron incorporation in the diamond shell was investigated by combining Scanning Electron Microscopy (SEM), UV Raman and X-ray Photoemission Spectroscopy (XPS) investigations. Such characterizations were compared to Scanning TEM (STEM) imaging, Energy Dispersive Spectroscopy (EDS) and Electron energy loss spectroscopy (EELS) performed on thin cross-sections of core-shells prepared by focused ion beam (FIB) milling.

Delaying a prescribed burn to scale up the restoration of alien‐invaded Lowland Sand Fynbos in South Africa

AbstractFire‐adapted species invading fire‐prone ecosystems in Mediterranean climate regions are difficult to control because they are equally responsive to restoration treatments. We assessed the efficacy of delaying a prescribed burn to promote the recruitment of native species in a Lowland Sand Fynbos ecosystem invaded by alien Acacia saligna. Acacia stands were felled and fallowed for 2 years before burning the slash and sowing pre‐treated fynbos seeds. We hypothesized that sowing pre‐treated fynbos seeds after fallowing cleared areas before burning would improve the regeneration of native species. Fallowing cleared areas would reduce the density of acacia seeds and post‐fire acacia recruitment while allowing felled acacia biomass to dry and decay over time leading to improved prescribed burn properties. Sowing pre‐treated fynbos seeds improved the recovery of native cover but had little effect on the recovery of native species diversity after 2 years. Although the rapid recruitment of annual native species did not affect acacia density, it might have contributed to reduced post‐fire acacia cover and allowed the native perennial species to establish. After 2 years of fallowing cleared areas, the density of acacia seeds and post‐fire acacia recruitment was reduced by ≈50% and 80% respectively. Although too dense to be outcompeted by recruited native species alone, this reduced acacia recruitment helped to decrease and delay the need for follow‐up acacia clearing as it was where burning occurred soon after felling acacia stands. The recruited native species managed to establish before the acacia emergents were removed unlike where burning occurs soon after felling and where native species were outcompeted resulting in the need for follow‐up sowing. In conclusion, building resilience against acacia resurgence by increasing the pool of sown species to recover a good cover of native species in combination with the timely removal of acacia recruits can help to scale up restoration.

The Effect of Giving Lamtoro Leaf Meal (Leucaena leucocephala) with Different Concentrations in Feed on the Growth and Survival Rate of Tilapia (Oreochromis niloticus)

This research aims to determine the effect of adding Lamtoro leaf flour to feed at different levels on the growth and survival of Tilapia. The test fish seeds used were relatively the same, namely approximately ± 5-8 cm, obtained from one of the members of the fish cultivator group in Kertayasa Village, Pangandaran. The containers used in this research were 12 with a net size of 1x1x1m3. The density of Tilapia seeds during the research was 20 fish/plot with the amount of feed provided being 5% of the fish biomass. The method used in this research was an experimental method using a Completely Randomized Design (CRD) with 4 treatments and 3 replications. The treatments used were (A) without giving Lamtoro leaf flour (control), (B) giving 5% Lamtoro leaf flour, (C) giving 10% Lamtoro leaf flour and (D) giving 15% Lamtoro leaf flour. This research was carried out for 40 days starting in May-June 2023, taking place in Kertayasa Village, Cijulang District, Pangandaran Regency. Parameters observed included absolute weight growth, feed conversion ratio (FCR) and survival rate (SR). The results showed that giving Lamtoro leaf flour to feed had a significant effect (P<0.05) on absolute weight growth with the highest treatment being treatment C (10% Lamtoro leaf flour) at 20 g, but no significant effect (P>0.05) to the value of feed conversion ratio and survival rate.

The Phytonutrient Content and Yield of Brassica Microgreens Grown in Soilless Media with Different Seed Densities

Microgreens are increasingly valued by consumers for their phytonutritional benefits. There is limited information to growers on the influence of growth media and seed density on antioxidant properties of Brassica microgreens. Therefore, the study was conducted to determine the effect of seedling media (Hygromix, Promix, and TS1) and seed density (4, 8, and 12 seeds per seed cavity) on morphological parameters, yield, color, antioxidant components, and their activities in radish (Raphanus sativus), cabbage (Brassica oleracea), and rocket (Eruca sativa) microgreens. Fourteen days after seeding, Promix at a seed density of 12 per cavity improved yield of radish, cabbage, and rocket microgreens. Irrespective of the seed density, all three Brassica microgreens grown in TS1 had higher leaf nitrogen, phosphorus, and calcium content. Interaction effects of Hygromix x seed densities were more pronounced on the antioxidant properties (DPPH and FRAP). These differences could be due to the physical properties of growth medium. Vitamin C and total glucosinolate were improved on Brassica microgreens grown in Hygromix at a seed density of 4 per cavity. Twelve seeds per cavity in Promix growth medium improved Brassica microgreens yield, whereas phytochemicals were most likely improved by growing media, Hygromix followed by TS1 and mineral content improved in TS1 followed by Hygromix at low seed density of 4 per cavity.

Potential contributions of the soil seed bank and seed rain for accelerating the restoration of riparian catchments in Australia

The quality and quantity of soil seed bank composition can play a key role in secondary succession restoration efforts such as those involved in this study, which concerned the restoration of damaged native sites in riparian environments in Victoria, Australia. The objective of this study of the restoration work was to determine the role played by naturally existing soil seed bank in the success of natural restoration in these restored and unmanaged riparian areas. In this regard, we sampled the soil seed bank, seed rain, seedlings in the field and vegetation cover from three sub catchments defined by restoration attempts which had been conducted (i) < 3 years, (ii) 4–8 years, and (iii) > 9 years previous to sampling. In addition, (iv) in order to provide comparative data, adjacent sites (iv) chosen for future restoration and (v) with remnant vegetation, were also sampled. From samples, a total of 8858 seedlings were recorded from the seed bank and the vegetation survey showed 170 species, with exotic species being more numerous than native. The seed rain (a total of 1422 seeds) was dominated by exotic species at all sites. When comparing the vegetation distribution and the seed rain composition, it was clear that whilst the seed bank was more promising as a comparative recruitment source of native species, there were still too many sites dominated by exotic species to rely on this as a long-term restoration strategy. However, this study indicated that there were significant variations in restoration potential among the sites, suggesting that some careful prior site selection for investment of restoration efforts is an important issue. As a consequence, we have recommended that a detailed understanding of the soil seed bank and seed rain species composition prior to the restoration is essential, since a positive seed bank composition with a significant relative density of native species seeds, will provide an indication of native species’ resilience and their potential for recovery. We therefore believe that the findings of this study will provide valuable information to natural resource management agencies regarding the strategy for prioritisation of restoration sites, which will be more beneficial than randomly selecting sites for habitat restoration. In addition, with successful sector restoration, it is expected that the increasing usefulness of the seed bank will allow further restoration of adjacent areas with time.

Engineering Properties of Onion Seeds for Sustainable Agricultural Machinery Design

The engineering properties of the crop are an important factor in effectively designing agricultural machines. In terms of onion seeding or planting, various physical, mechanical, and frictional properties play a crucial role in the development of planting machines and performance assessment. The study on the engineering properties of onion seeds and their implications for agricultural machinery design supports the adoption of sustainable agricultural practices. Efficient and precise planting systems can optimize resource utilization, reduce wastage, and enhance overall agricultural productivity. This focus on engineering aspects in machinery design indirectly contributes to sustainable agriculture practices, which prioritize minimizing environmental impacts while ensuring food security. Ultimately, by emphasizing the importance of engineering properties, the study promotes the development of agricultural systems that align with sustainability goals. In this study, various engineering properties of onion seeds concerning the different soaking times have been studied. An experiment was performed to assess the change in engineering properties of onion seeds (Gavran, Puna fursungi, and KSP-117) by soaking them in water with a predefined duration (Dry seed, Day 1 and Day 2). The average moisture content of onion seeds varied from 9.44 to 40.87 % (d.b.). Sphericity, aspect ratio, geometric mean diameter, and thousand seed weight varied in the range from 0.72 to 0.77, 0.71 to 0.76, 2.05 to 2.18 mm, and 3.50 to 6.75 g, respectively. The bulk density of onion seeds was observed in the range of 489.64 to 526.24 kg/m3. It was observed that there was a gradual increment in bulk density with an increase in soaking time. However, a gradually decreasing trend was observed in the case of true density. The true density of onion seeds varied from 1127.14 to 1245.64 kg/m3. The coefficient of friction of onion seeds on a selected material (Wood, Plastic, Mild steel, and Aluminum) showed gradual growth concerning the soaking time.

The effect of moisture contents on the physical properties of both bambara groundnut seeds and pods in South Africa

Bambara groundnut (Vigna subterranean (L) Verdc) is an indigenous African crop. In South Africa, the crop is grown by rural subsistence farmers. This crop is classified as a drought-tolerant crop and it can produce good yields in poor soil conditions. However, statistics show that Bambara groundnut production is currently neglected by industries due to the lack of research on the crop focused on postharvest technologies, and agro-processing. Current research on the crop is mostly focused on agronomic and growing characteristics. Data on the physical properties and processing equipment for the Bambara groundnuts are limited. The objectives of this study were to investigate the effect of moisture contents on both Bambara groundnut seeds (shelled) and pods (unshelled). The physical properties of the pods and seeds were measured at three moisture content levels. The finding showed that axial dimensions, geometric mean diameter, sphericity, volume, and weight increase as moisture content increases. The static coefficient of friction of seeds and pods increased from 0.15 to 0.19 and 0.29 to 0.31, respectively. Simirlarly, the bulk density of shelled and unshelled groundnuts increased from 500 to 955, and 355 to 422 kg.m-3, respectively. The results also showed that the true density of seeds rose from 994 to 1832 kg.m-3 and for the unshelled groundnuts it increased linearly from 532 to 655 kg.m-3. The required forces for cracking both bambara groundnut seeds and kernels showed a declining trend as moisture increased from 6 to 20%. The cracking forces required for Bambara groundnuts kernels at 6, 15, and 20 % are 32.5 ±12 N, 29.9 ±15.3 N, and 28.9 ±9 N, respectively. As the moisture increased, the data deviation from the mean decreased from 16.30 to 10.1 N. In terms of designing agro processing eqiupment or machinary such as a shelling machine, the physical properties from the lower moisture content are recommended. Key words: cracking force, physical properties, moisture content, Bambara groundnuts

Etching Kinetics of Nanodiamond Seeds in the Early Stages of CVD Diamond Growth.

We present an experimental study on the etching of detonation nanodiamond (DND) seeds during typical microwave chemical vapor deposition (MWCVD) conditions leading to ultra-thin diamond film formation, which is fundamental for many technological applications. The temporal evolution of the surface density of seeds on the Si(100) substrate has been assessed by scanning electron microscopy (SEM). The resulting kinetics have been explained in the framework of a model based on the effect of the particle size, according to the Young-Laplace equation, on both chemical potential of carbon atoms in DND and activation energy of the reaction with atomic hydrogen. The model describes the experimental kinetics of seeds' disappearance by assuming that nanodiamond particles with a size smaller than a "critical radius," r*, are etched away while those greater than r* can grow. Finally, the model allows to estimate the rate coefficients for growth and etching from the experimental kinetics.

Gram-Scale Continuous Flow Synthesis of Silver-on-Silica Patchy Nanoparticles with Widely Tunable Resonances for Plasmonics Applications

Extensive research has been conducted on colloids that incorporate nanostructured noble metals, motivated in particular by their highly tunable optical properties. However, the lack of approaches that offer reproducibility, tunability, and scalable production is limiting their exploitation in many application areas. Here, we present an innovative process for the controlled formation of silver patches on silica nanospheres using gold nanocrystal seeds. The synthesis of the seeds and their attachment in very small numbers to the silica spheres is achieved without employing any surfactants, stabilizers, or linker molecules. Using advanced transmission electron microscopy techniques, we show that electroless deposition of nanostructured silver occurs at the introduced seeds and leads to a central protrusion from the metal patches not observed in earlier, seed-free work. We demonstrate that both seeding and growth processes can be achieved in millimixer flow reactors. With this simple and scalable approach, we provide compelling evidence for the use of seeds in producing targeted morphology and function. Specifically, patch size and optical properties can be tailored in a predictive manner by adjusting the density of seeds on the silica nanospheres as well as reagent concentrations during growth. As a result, our process can be used to obtain colloidal dispersions with localized surface plasmon resonance peaks anywhere in the range 400 to nearly 1300 nm. We confirm the scalability of our method by operating the growth process for around 70 min. Apart from changes in the first few minutes, the product properties remained rather stable and over a gram of high quality silver patch-coated silica could be recovered. Our approach opens up exciting new avenues for plasmonics applications, which typically require large amounts of nanoparticles with specifically designed optical properties. These include color and IR pigments, photocatalysts, and as light management components in optoelectronic devices like photovoltaic cells.

Seed Density as a New Predictive Index of Seed Migration in Brachytherapy for Prostate Cancer Using Iodine-125 Loose Seed

This study aimed to examine the usefulness of seed density as a predictor of seed migration in patients with prostate cancer who received brachytherapy using Iodine-125 loose seed. From May 2006 to April 2016, 320 patients with localized prostate cancer underwent transperineal brachytherapy using iodine-125 loose seeds. Among them, 202 (63.1%) patients received brachytherapy monotherapy and 118 (36.9%) received combined brachytherapy and external beam radiotherapy. Seed density was calculated using the following formula: seed density = implanted seed number/prostate volume. All patients underwent radiography of the chest, abdomen and pelvis, and computed tomography at 1 day, 1 month, and 1 year after brachytherapy to evaluate the presence of seed migration. In total, the number of implanted seeds was 21,876. Seed migration was detected in 92 (28.8%) patients. Of a total of 21,876 seeds, 144 (0.66%) showed migration. The number of needles, number of seeds, and seed density were significantly higher in the group with migration than in the group without migration (p = 0.05). The ROC cutoff values for prostate volume, number of needles, number of seeds, and seed density were 20.9 cc, 21, 65, and 3.0, respectively. In the univariate analysis, prostate volume, number of needles, number of seeds, seed density, and treatment modality were all significant factors in predicting migration (p = 0.05). In the multivariate analysis, seed density and treatment modality were significant factors in predicting migration (p = 0.05). Seed density is useful for predicting seed migration. In cases with seed density > 3.0, it is necessary to take measures such as considering the use of stranded seeds.

QTL analysis and candidate gene prediction for seed density per silique by QTL-seq and RNA-seq in spring Brassica napus L.

Seed density per silique (SD) is an important agricultural trait and plays an important role in the yield performance of Brassica napus L. (B. napus). In this study, a genetic linkage map was constructed using a double haploid (DH) population with 213 lines derived from a cross between a low SD line No. 935 and a high SD line No. 3641, and a total of 1,098,259 SNP (single-nucleotide polymorphisms) markers and 2,102 bins were mapped to 19 linkage groups. Twenty-eight QTLs for SD were detected on chromosomes A02, A04, A05, A09, C02, C03, C06, and C09 of B. napus, of which eight QTLs were on chromosome A09 and explained 5.89%-13.24% of the phenotypic variation. Furthermore, a consistent QTL for SD on chromosome A09, cqSD-A9a, was identified in four environments by QTL meta-analysis, explaining 10.68% of the phenotypic variation. In addition, four pairs of epistatic interactions were detected in the DH population via QTL epistasis analysis, indicating that SD is controlled not only by additive effects but also by epistatic effects that play an important role in spring B. napus., but with little environmental effect. Moreover, 18 closely linked SSR markers for cqSD-A9a were developed, as a result, it was mapped to a 1.86Mb (7.80-9.66 Mb) region on chromosome A09. A total of 13 differentially expressed genes (DEGs) were screened in the candidate interval by RNA-seq analysis, which were differentially expressed in buds, leaves and siliques both between and siliques both between two parents and two pools of extremely high-SD and low-SD lines in the DH population. Three of 13 DEGs were possible candidate genes that might control SD: BnaA09g14070D, which encodes a callose synthase that plays an important role in development and stress responses; BnaA09g14800D, a plant synaptic protein that encodes a membrane component; and BnaA09g18250D, which is responsible for DNA binding, transcriptional regulation, and sequence-specific DNA binding and is involved in the response to growth hormone stimulation. Overall, these results lay a foundation for fine mapping and gene cloning for SD in B. napus.

Weed Seed Bank Density in Seven-Year-Old Conservation in No-Till System

Weed management remains a challenge when introducing new cropping systems. In Lebanon, farmers are increasingly adopting conservation agriculture (No-till) because it saves energy and reduces water and nutrient erosion. However, introducing a new system will cause a significant shift in production and management practices and is expected to produce novel weed management challenges. Thus, knowledge of soil seed banks of weeds in such systems is vital in designing effective weed management strategies. The objective of this research was to assess the size of the weed seed bank in seven-year-old conservation no-till fields. Soil samples were collected from established till and no-till fields at a depth of 0-5 cm. Transient and persistent weed seeds banks were evaluated. Results provide tangible evidence that the weed seed bank at a depth between 0-5cm in no-till system is greater than in till system. The no-till fields contained almost seven times the density of monocot and dicot weed seeds than in the conventional tilled fields. Ongoing work that builds on present results will help gain knowledge pertaining to weed seed bank dynamics in no-till system compared with conventionally tilled system.

QTL mapping for seed density per silique in Brassica napus

Seed density per silique (SDPS) and valid silique length (VSL) are two important yield-influencing traits in rapeseed. SDPS has a direct or indirect effect on rapeseed yield through its effect on seed per silique. In this study, a quantitative trait locus (QTL) for SDPS was detected on chromosome A09 using the QTL-seq approach and confirmed via linkage analysis in the mapping population obtained from 4263 × 3001 cross. Furthermore, one major QTL for SDPS (qSD.A9-1) was mapped to a 401.8 kb genomic interval between SSR markers Nys9A190 and Nys9A531. In the same genomic region, a QTL (qSL.A9) linked to VSL was also detected. The phenotypic variation of qSD.A9-1 and qSL.A9 was 53.1% and 47.6%, respectively. Results of the additive and dominant effects demonstrated that the expression of genes controlling SDPS and VSL were derived from a different parent in this population. Subsequently, we identified 56 genes that included 45 specific genes with exonic (splicing) variants. Further analysis identified specific genes containing mutations that may be related to seed density as well as silique length. These genes could be used for further studies to understand the details of these traits of rapeseed.

Long-term active restoration of degraded grasslands enhances vegetation resilience by altering the soil seed bank

Long-term active restoration is often employed to restore degraded grasslands. The establishment of a viable soil seed bank is the key to successful restoration, as it enhances the resilience of vegetation. However, little is known of how the soil seed bank affects vegetation resilience following long-term active restoration of degraded grasslands. We determined seed abundance and species composition of the soil seed bank and soil properties and vegetation resilience of intact, degraded, and long-term (>10 years) actively restored grasslands on the Tibetan plateau (3900–4200 m a.s.l.). The plant-soil-seed bank quality index and structural equation modelling (SEM) were used to assess the effect of the soil seed bank on vegetation resilience. After long-term (>10 years) active restoration of degraded grasslands by sowing seeds of native plant species, the densities of transient and persistent seeds increased by 5%, but seed richness (number of species) decreased by 25% when compared with degraded grasslands. This occurred largely as a result of an increase in grass but decrease in forb seeds. Persistent seeds of grasses play an important role in the productivity of restored grasslands, while the density of persistent seeds serves as an indicator of the resilience of vegetation. A combination of the plant community and soil properties determined seed density. Here, we show for the first time that long-term active restoration enhances vegetation resilience of grasslands by altering the soil seed bank. A high seed density of sown Gramineae and a low seed density of forbs in the soil seed bank is a key to the successful active restoration of degraded grasslands.

EVALUATION OF WHEAT GENOTYPES WITH DIFFERENT SEEDING DENSITIES IN SOUTHERN SONORA, MEXICO

An evaluation of seeding density (60, 120, and 180 kg ha-1) with six durum wheat and two bread wheat genotypes, was carried out at the Norman E. Borlaug Experimental Station during the fallwinter 2021-2022 crop season. An experimental alpha lattice design was used with three replications; the plot size consisted of two beds five meters long, separated by 80 cm and with three rows. Highly significant statistical differences were found between seed densities and between the genotypes evaluated; the best seed densities (p ≤ 0.05) were 120 and 180 kg ha-1, with grain yields of 7,319 and 7,425 kg ha-1, respectively. Genotypes with the highest grain yield were: STOT (STOT//ALTAR 84/ALD/3/PATKA_7/YAZI_1/4/SOMAT_3/PHAX_1// TILO_1/LOTUS_4/5/SOOTY_9/RASCON_37//WODUCK/CHAM_3/6/BAROYECAORO C2013/7/WID22202/4/SORA/2*PLATA_12//SOMAT_3/3/AJAIA_12/F3LOCAL(SEL.ETHIO. 135.85)//PLATA_13/5/CF4-JS 21//TECA96/TILO_1, CDSS13B00720T-099Y-099M-1Y-4M0Y) with 7,669 kg ha-1, followed by Noroeste C2021 (7,561), Don Lupe C2020 (7,463), Borlaug 100 (7,392), CIANO M2018 (7,296), TARRO (TARRO_1/2*YUAN_1//AJAIA_13/ YAZI/3/SOMAT_3/PHAX_1//TILO_1/LOTUS_4/4/CANELO_8//SORA/2*PLATA_12/5/CBC 501CHILE/GUANAY/4/CNDO/PRIMADUR//HAI-OU_17/3/SNITAN/7/ALTAR84/ BINTEPE85/3/STOT//ALTAR 84/ALD/4/POD_11/YAZI_1/5/VANRRIKSE_12/SNITAN/6/ SOOTY_9/RASCON_, CDSS14B00835T-099Y-099M-5Y-1M-0Y) (7,282), CENEB Oro C2017 (7,271), while CIRNO C2008 the regional check, showed the lowest grain yield (6,019 kg ha-1).