Plant Populations Research Articles

Histological characteristics of the Indigofera zollingeriana mutant 2 (M2) population resulting from gamma-ray irradiation grown in saline soil

Abstract Indigofera zollingeriana plant has been used by Farmers as a feed plant, which contains high protein and is very good as a source of forage to increase livestock productivity. However, its development is constrained by the limited availability of land, so it is necessary to conduct research for its development on marginal land. This study aims to evaluate the effect of salinity on histological diversity of four populations of mutant 2 (M2) I. zollingeriana resulting from gamma-ray irradiation in saline fields. The study was conducted in a randomized block design (RBD) with four treatments of the M2 I. zollingeriana population resulting from gamma-ray irradiation with 6 replications. Plant population were irradiated at 0, 100, 200, and 300 gray. Parameters observed were: characteristics of stomata, tricoma and cuticle. The results showed that the diversity of stomata and cuticles were not significantly different in each treatment. However, the number of tricoma have a significant effect, namely on the parameter number of tricoma. The highest number of tricoma was found in the 200 gray with a number of 17. Significantly different from the other treatments (0, 100 and 300 gray) each obtained a total of 9.83, 12.17 and 11.67. It was concluded that the radiation dose at the 200 gray level has the genetic potential to be continued at the adaptation test stage to further support the formation of new salinity tolerant Indigofera varieties.

Support for Baker's law: Facultative self-fertilization ability decreases pollen limitation in experimental colonization.

The ability to self-fertilize is predicted to provide an advantage in colonization because a single individual can reproduce and establish a next generation in a new location regardless of the density of mates. While there is theoretical and correlative support for this idea, the strength of mate limitation as a selective agent has not yet been delineated from other factors that can also select for self-fertilization in colonization of new habitats. We used known mating-system variation in the American bellflower (Campanula americana) to explore how plants' ability to self-fertilize can mitigate density-dependent reproduction and impact colonization success. We created experimental populations of single individuals or a small number of plants to emulate isolated colonization events. These populations were composed of plants that differed in their ability to self-fertilize. We compared pollen limitation of the single individuals to that of small populations. Experimental populations of plants that readily self-fertilize produced consistent seed numbers regardless of population size, whereas plants with lower ability to self-fertilize had density-dependent reproduction with greater seed production in small populations than in populations composed of a single individual. We experimentally isolated the effect of mate limitation in colonization and found that it can select for increased self-fertilization. We show the benefit of self-fertilization in colonization, which helps to explain geographic patterns of self-fertilization and shows support for Baker's law, a long-held hypothesis in the field of mating-system evolution.

Commercial maize hybrids have smaller root systems after 80 Years of breeding

Roots have gained attention for their role in improving plant function in high-stress environments and providing ecosystem services such as soil organic carbon storage. An important step in breeding for enhanced root phenotypes is understanding how root traits have changed historically due to selection for yield and other aboveground traits. However, among the few era panel studies focused on roots, there are conflicting findings about how breeding has altered traits such as root system length and biomass, while other traits such as root depth distribution, root size class distribution, and tissue quality remain largely unexplored. Our aim was to assess breeding-driven changes in root traits that are relevant to resource acquisition and soil carbon sequestration. We grew twelve maize (Zea mays L.) hybrids from the Corteva/Pioneer ERA panel, spanning from 1936 to 2014, in 1.5 m deep mesocosms. At the eight-leaf stage, intact root systems were imaged and analyzed using a custom root phenotyping platform, and roots and shoots were subjected to carbon and nitrogen analysis and Diffuse Reflectance FTIR to assess variation in tissue composition. We found that the newest hybrids produced 40% less root biomass and 36% less root length than the oldest hybrids, with declines of 0.024 g year−1 (s.e.: 0.005, p < 0.01) and 0.86 m year−1 (s.e.: 0.23, p < 0.01) with no changes in maximum rooting depth, which averaged 113 cm (±5.62). , and no directional shifts in chemical composition. We also found a decline in the root-to-shoot ratio from 0.58 g g−1 to 0.46 g g−1 (s.e.: 0.0006, p < 0.05). Our results suggest that selection for yield has indirectly decreased root system size over 80 years of maize breeding. Smaller root systems of modern hybrids may contribute to the higher optimum plant populations and higher yields of modern maize hybrids.

The role of the plant microbiome for forestry, agriculture and urban greenspace in times of environmental change.

This Lilliput article provides a literature overview on ecological effects of the plant microbiome with a focus on practical application in forestry, agriculture and urban greenspace under the spectre of climate change. After an overview of the mostly bacterial microbiome of the model plant Arabidopsis thaliana, worldwide data from forests reveal ecological differentiation with respect to major guilds of predominantly fungal plant root symbionts. The plant-microbiome association forms a new holobiont, an integrated unit for ecological adaptation and evolutionary selection. Researchers explored the impact of the microbiome on the capacity of plants to adapt to changing climate conditions. They investigated the impact of the microbiome in reforestation programs, after wildfire, drought, salination and pollution events in forestry, grasslands and agriculture. With increasing temperatures plant populations migrate to higher latitudes and higher altitudes. Ecological studies compared the dispersal capacity of plant seeds with that of soil microbes and the response of soil and root microbes to experimental heating of soils. These studies described a succession of microbiome associations and the kinetics of a release of stored soil carbon into the atmosphere enhancing global warming. Scientists explored the impact of synthetic microbial communities (SynComs) on rice productivity or tea quality; of whole soil addition in grassland restoration; or single fungal inoculation in maize fields. Meta-analyses of fungal inoculation showed overall a positive effect, but also a wide variation in effect sizes. Climate change will be particularly prominent in urban areas ("urban heat islands") where more than half of the world population is living. Urban landscape architecture will thus have an important impact on human health and studies started to explore the contribution of the microbiome from urban greenspace to ecosystem services.

Effect of Planting Distance and Plant Population on Growth and Yields Sunflower (Helianthus annus L.)

Effect of Planting Distance and Plant Population on Growth and Yields Sunflower (Helianthus annus L.)

Effects of Sheep Grazing and Nitrogen Addition on Dicotyledonous Seedling Abundance and Diversity in Alpine Meadows

Seedling is a crucial stage in the growth and development of plants, and the expansion and persistence of plant populations can be achieved through seed regeneration. Sheep grazing, fertilization, light, soil moisture, vegetation diversity and biomass, and litter all have potential impacts on species regeneration. We measured vegetation diversity, annual net primary productivity (ANPP), litter, ground photosynthetically active radiation (PAR), and soil moisture of alpine meadows under sheep grazing and nitrogen addition treatments, and studied their effects on the dicotyledonous seedling abundance and diversity using linear regression models (LMs) and structural equation models (SEMs). We found that sheep grazing reduced ANPP, increased vegetation diversity and PAR, and decreased soil moisture. Fertilization increased ANPP and litter, decreased vegetation diversity and PAR, but had no effect on soil moisture. Sheep grazing and fertilization both reduced the abundance of dicotyledonous seedlings, and simultaneously fertilization can reduce the diversity of dicotyledonous seedlings, while sheep grazing had no effect on the diversity of dicotyledonous seedlings. LMs showed that vegetation diversity, ANPP, and litter, rather than light and soil moisture, affected dicotyledonous seedling abundance and diversity. SEMs revealed that sheep grazing and fertilization indirectly influenced seedling regeneration through vegetation diversity rather than ANPP and litter. Our research will increase our understanding of the dicotyledonous plant regeneration process in alpine grasslands and facilitate the development of strategies for management and protection of alpine grassland.

Protocol for assessing invasive plant populations

Protocol for assessing invasive plant populations

New insights into the evolution and local adaptation of the genus Castanea in east Asia.

Chestnut plants (Castanea) are important nut fruit trees worldwide. However, little is known regarding the genetic relationship and evolutionary history of different species within the genus. How modern chestnut plants have developed local adaptation to various climates remains a mystery. The genomic data showed that Castanea henryi first diverged in the Oligocene ~31.56 million years ago, followed by Castanea mollissima, and the divergence between Castanea seguinii and Castanea crenata occurred in the mid-Miocene. Over the last 5 million years, the population of chestnut plants has continued to decline. A combination of selective sweep and environmental association studies was applied to investigate the genomic basis of chestnut adaptation to different climates. Twenty-two candidate genes were associated with temperature and precipitation. We also revealed the molecular mechanism by which CmTOE1 interacts with CmZFP8 and CmGIS3 to promote the formation of non-glandular trichomes for adaptation to low temperature and high altitudes. We found a significant expansion of CER1 genes in Chinese chestnut (C. mollissima) and verified the CmERF48 regulation of CmCER1.6 adaptation to drought environments. These results shed light on the East Asian chestnut plants as a monophyletic group that had completed interspecific differentiation in the Miocene, and provided candidate genes for future studies on adaptation to climate change in nut trees.

Elevated nitrogen and co-evolution history with competitors shape the invasion process of Galinsoga quadriradiata

Abstract Invasive plants usually experience population differentiation as they expand from their initial invasive range to the edge. Moreover, invasive plants usually encounter competitors which shared different co-evolutionary histories with them. These factors may lead to varying responses of invasive plant populations to elevated nitrogen deposition during expansion. However, this issue has received limited attention in prior research. To address these challenges, we conducted a greenhouse experiment to investigate how population differentiation of Galinsoga quadriradiata interacts with the presence of various competitors in response to increased nitrogen deposition. Competitor types (new or old that shared short or long co-evolutionary history with the invader, respectively) were set to compete with the invasive central and edge populations under different nitrogen addition treatments. Individuals from the central population of G. quadriradiata, originating from the initial invasion range, showed greater total mass, reproduction and interspecific competitiveness compared with the edge population. Nitrogen addition improved growth and reproductive performance in both populations, and the central population had a stronger response compared with the edge population. The performance of G. quadriradiata was inhibited more effectively by old competitors than new competitors. Our results indicate that population differentiation occurs in terms of growth and competitiveness during the range expansion of G. quadriradiata, with the central population exhibiting superior performance. Co-evolutionary history with competitors is considered unfavorable for invasive plants in this study. Our results highlight the combined effects of population differentiation in invasive species and their co-evolution history with competitors in the context of global change factors.

The Populations of Two Differently Medicine-Used Plants of Hedyotis diffusa and Hedyotis corymbosa Shoot-Assembling Rich Bacterial and Fungal Communities with Varied Compositions but Conserved Structures.

The plant-colonized microbial communities have closely micro-ecological effects on host plant growth and health. There are many medicinal plants in the genus Hedyotis, but it is yet unclear about the shoot-assembled bacterial and fungal communities (SBFC) of Hedyotis plants. Hence, eight plant populations of Hedyotis diffusa (HD) and H. corymbosa (HC) were evaluated with 16S rRNA gene and ITS sequences, for comparing the types, abundance, or/and potential functions of SBFC at plant species- and population levels. In tested HD- and HC-SBFC, 682 fungal operational taxonomic units and 1,329 bacterial zero-radius operational taxonomic units were identified, with rich species compositions and varied alpha diversities. Notably, the SBFC compositions of HD and HC plant populations were exhibited with partly different types and abundances at phylum and genus levels but without significantly different beta diversities at plant species and population levels. Typically, the SBFC of HD and HC plant populations were presented with abundance-different biomarkers, such as Frankiaceae and Bryobacteraceae, and with similar micro-ecological functions of microbial metabolisms of lipids, terpenoids,and xenobiotics. Taken together, HD- and HC-SBFC possessed with varied rich compositions, conservative taxonomic structures, and similar metabolic functions, but with small-scale type and abundance differences at plant species- and population- levels.

Genomic signatures of past megafrugivore‐mediated dispersal in Malagasy palms

Abstract Seed dispersal affects gene flow and hence genetic differentiation of plant populations. During the Late Quaternary, most fruit‐eating and seed‐dispersing megafauna went extinct, but whether these animals have left signatures in the population genetics of their food plants, particularly those with large, ‘megafaunal’ fruits (i.e. &gt;4 cm—megafruits), remains unclear. Here, we assessed the population history, genetic differentiation and recent migration among populations of four animal‐dispersed palm (Arecaceae) species with large (Borassus madagascariensis), medium‐sized (Hyphaene coriacea, Bismarckia nobilis) and small (Chrysalidocarpus madagascariensis) fruits on Madagascar. We integrated double‐digest restriction‐site‐associated DNA sequencing (ddRAD) of 167 individuals from 25 populations with (past) distribution ranges for extinct (e.g., giant lemurs and elephant birds) and extant seed‐dispersing animals, landscape and human impact data, and applied linear mixed‐effects models to explore the drivers of genetic variation in Malagasy palms. Palm populations that shared more megafrugivore species in the past had lower genetic differentiation than populations that shared fewer megafrugivore species. This suggests that megafrugivore‐mediated seed dispersal in the past may have led to frequent gene flow among populations. In comparison, extant frugivore diversity only decreased genetic differentiation in the small‐fruited palm. Furthermore, genetic differentiation of all palm species decreased with landscape connectivity (i.e. environmental suitability, forest cover and river density) and human impact (i.e. road density), while migration rates of the small‐fruit palm increased with road density. Synthesis. Our results suggest that the legacy of megafrugivores regularly achieving long dispersal distances is still reflected in the population genetics of palms that were formerly dispersed by such animals. Furthermore, low genetic differentiation was possibly maintained after the megafauna extinctions through alternative dispersal (e.g. human‐ or river‐mediated), long generation times and long lifespans of these megafruit palms. Our study illustrates how species interactions that happened &gt;1000 years ago can leave imprints in their population genetics.

Induction of Somatic Embryogenesis of Pontianak Siamese Orange Cotyledon Cultures on Murashige Skoog Media with the Addition of 2,4-D and Kinetin

Conventional citrus propagation has weaknesses, one of which is susceptible to CVPD(Citrus Vein Phloem Degeneration) and other diseases which are the main cause of the decline in population and production of pontianak siam orange plants in West Kalimantan. One alternative to in vitro propagation of citrus seedlings is the induction of somatic embryogenesis. The purpose of the study was to obtain the best combination of 2,4-D and kinetin concentrations for callus induction and somatic embryo induction from Pontianak siam orange cotyledon explants, observing the developmental phase (stage) of embryos formed. The implementation of the study used a factorial completely randomized design (CRD) consisting of 2 factors. The first factor is the concentration of 2,4-D consisting of 4 concentration levels, namely 0; 0.5; 1; 1.5; 2 mg/L. The second factor is kinetin concentration consisting of 4 concentration levels, namely 0; 0.5; 1; 1.5; 2 mg/L.The observation parameters include the time of callus emergence (hst), the percentage of explants forming callus (%), the texture and color of the callus, observing the stage of the embryo found. The results showed that 72% of treatments were able to induce callus from pontianak siam orange cotyledons with an average callus appearance at 7 hst. The callus formed is compact and crumbly with varied callus colors, namely white, yellowish, greenish and brownish. The best treatment that produces embryogenic callus is the combination of D0.5K0.5; D1K1; D0.5K1.5; D1.5K1.5 and D2K2 with the characteristics of crumbly callus and yellowish and brownish colors. The results of microscopic observations found that the somatic embryo phase formed was the pro-embryo phase.

Sphenoptera sp. (Buprestidae: Coleoptera) threatening wild cancer bush (Sutherlandia frutescens) population

Cancer bush (Sutherlandia frutescens) is a medicinal plant indigenous to Southern Africa, important in the treatment of diverse human diseases and ailments. The rampant harvesting in the wild has threatened many indigenous medicinal plants. To safeguard this national treasure, cultivation has been recommended. Recently, substantial insect damage to the wild population of cancer bush in the Limpopo province has been observed. Currently, there are no reports of insect pests associated with cancer bush, hence the objective of this study was to use morphological and molecular tools in the identification of insect pest associated with extensive damage to wild cancer bush populations in Makgophong and Tubatse, Limpopo Province, South Africa from March to June 2023. Plants were cut longitudinally to expose insects inside the stem, and a microscope at 40X magnification, was used to examine the morphological characteristics of insects found. Insect species found were further confirmed using mitochondrial cytochrome c oxidase subunit 1 gene (COI). All life stages of the beetle except the egg stage were observed in the plant, and the morphological and molecular examination of these specimens revealed that the adults and larvae corresponded with the descriptions of Sphenoptera species. This is the first positive confirmation of Sphenoptera species associated with cancer bush and urgent development of management strategies is needed if this plant population (species) is to be conserved.

Intraspecific variation in responses to extreme and moderate temperature stress in the wild species, Solanum carolinense (Solanaceae).

Adaptation or acclimation to local temperature regimes has often been used as a proxy for predicting how plant populations will respond to impending novel conditions driven by human-caused climate change. To understand how plants may successfully respond to increasing air temperatures (extreme and moderate) in the future, we explored how temperature tolerance traits differ in populations of Solanum carolinense from northern (MN) and southern (TX) regions of the continental USA in a two-experiment study. In the first experiment, we compared the heat and cold tolerance in vegetative (sporophyte) and reproductive (male gametophyte) traits. In the second experiment, we studied if long-term heat influences plant development by examining how development in moderate heat affected reproductive structures and reproductive success. We found that temperature sensitivity differed between southern populations, which regularly experience extreme heat, and northern populations which do not. In contrast to our expectations, northern populations appeared more heat-tolerant than southern populations for vegetative traits such as chlorophyll stability and reproductive traits such as pollen germination. Our results are consistent with a heat-avoidance, rather than tolerance mechanism to mitigate extreme heat during pollen germination. In the second experiment, plants developing under the moderate heat treatment had significantly smaller reproductive structures and reduced seed production (27% fewer seeds on average than in the control treatment). Reproductive structures that developed in moderate heat were also reduced in size, particularly in the northern populations relative to populations from the south. We conclude that rising temperatures have the potential to incur substantial negative consequences for the reproductive success of individuals in this species and that some populations already mitigate stressful temperature conditions through phenotypic plasticity.

Global insect herbivory and its response to climate change

Herbivorous insects consume a large proportion of the energy flow in terrestrial ecosystems and play a major role in the dynamics of plant populations and communities. However, high-resolution, quantitative predictions of the global patterns of insect herbivory and their potential underlying drivers remain elusive. Here, we compiled and analyzed a dataset consisting of 9,682 records of the severity of insect herbivory from across natural communities worldwide to quantify its global patterns and environmental determinants. Global mapping revealed strong spatial variation in insect herbivory at the global scale, showing that insect herbivory did not significantly vary with latitude for herbaceous plants but increased with latitude for woody plants. We found that the cation-exchange capacity in soil was a main predictor of levels of herbivory on herbaceous plants, while climate largely determined herbivory on woody plants. We next used well-established scenarios for future climate change to forecast how spatial patterns of insect herbivory may be expected to change with climate change across the world. We project that herbivore pressure will intensify on herbaceous plants worldwide but would likely only increase in certain biomes (e.g., northern coniferous forests) for woody plants. Our assessment provides quantitative evidence of how environmental conditions shape the spatial pattern of insect herbivory, which enables a more accurate prediction of the vulnerabilities of plant communities and ecosystem functions in the Anthropocene.

Evaluation of High Yielding Groundnut Varieties for North Transitional Zone of Karnataka State, India

Groundnut (Arachishypogaea L.) is an important oil seed crop grown in the arid andsemi-aridtropics of India under rainfed condition. The productivity is around 800 kg ha-1 in Karnataka as against national productivity of 1500 kg ha-1. The reasons for low productivity are many among them lack of improved variety in groundnut cultivation. Hence, study conducted to evaluate the high yielding groundnut varieties on farmers filed under farmers participatory mode approach. On field 25 FLD’s were planned by AICRP on Groundnut, MARS, UAS, Dharwad, Karnataka on farmers’ participatory mode approach under National Mission on Oilseeds and Oil Palm(NMOOP) programme and were conducted during kharif2021 with 25 farmers from Dharwad district. Each farmers field was considered as replication (25 no.) with 5 varieties as treatments and data was analysed statistically using Randomized complete block design. Statistical significance was tested with F test at 5 per cent level of probability. The study revealed that Dh-256(2850 kg ha-1) and K-1812 (Kadri Lepaxi) (2745 kg ha-1) recorded statistically on far dry pod yield. However, Dh-256 numerically out yielded K-1812 to the extent of 105 kg ha-1. Haulm yield when compared to the other varieties. A significant reduction in stem rot incidence was observed with respect to Dh-256(3.5%), K-1812(3.8%), G2-52(4.5%) and GPBD-4(4.7%) when compared to JL-24(8.1%) which resulted significant reduction plant population of JL-24 at harvest though it was having higher harvest index. The additional cost of cultivation of Rs. 2000 was spent on JL-24 to manage foliar diseases. Significantly higher gross returns were of Rs.148405 ha-1 and Rs.143460 ha-1, respectively by cultivating Dh-256 and K-1812 as against Rs.115740 ha-1 and Rs. 98728 ha-1 of local improved popular variety GPBD-4 and farmers check variety JL-24, respectively. From the results, farmers were very satisfied with Dh-256 and K-1812 newly released varieties of UAS, Dharwad, Karnataka and ARS, Kadiri, Andhra Pradesh. During, kharif2021, groundnut crop growth season was normal (496 mm from South West Monsoon i.e., June to September) for the Dharwad district and it was 4% higher than normal rainfall of 479 mm for the same period in the region, Further, groundnut crop not suffered due to dry spell any point of its growing period.

Stability in plant-pollinator communities across organizational levels: present, gaps, and future.

Abstract. The study of ecological stability continues to fill the pages of scientific journals almost seven decades after the first ecologists initiated this line of research. The many advances in this field have focused on understanding the stability of populations, communities or functions within single guilds or trophic levels, with less research conducted across multiple trophic levels and considering the different interactions that relate species to each other. Here, we review the recent literature on the multiple dimensions of ecological stability specifically within plant-pollinator communities. We then focus on one of stability´s dimensions, temporal invariability, and adapt an existing partitioning framework that bridges invariability and synchrony measures across spatial scales and organizational levels to accommodate interactions between plants and their pollinators. Finally, we use this framework to analyse temporal invariability in plant reproductive success, partitioning it on invariability and synchrony components across plant and pollinator populations and communities, as well as their interactions, using a well-resolved dataset that encompasses data for two years. Our review of the literature points to several significant gaps in our current knowledge, with simulation studies clearly overrepresented in the literature as opposed to experimental or empirical approaches. Our quantitative approach to partitioning invariability shows similar patterns of decreasing temporal invariability across increasing organizational levels driven by asynchronous dynamics amongst populations and communities, which overall stabilize ecosystem functioning (plant reproductive success). This study represents a first step towards a better comprehension of temporal invariability in ecosystem functions defined by interactions between species and provides a blueprint for the type of spatially replicated multi-year data that needs to be collected in the future to further our understanding of ecological stability within multi-trophic communities.

The Science of Vegetation with Reference to India

Pt. I Vegetation is the sum total of plant population covering a region and its descrete units circumscribed by characteristic environment, are communities. The species content is the flora. The physical and the biological surroundings characterise the environmental complex. Both plants and their environment are dynamic systems interacting within and with each other. The amplitude of variations in the environment is generally met with synchronised adaptive responses of the plants in time and space. Differentiation of ecads and ecotypes within the plastic species is the result. However, many forms and invaders may get eliminated also if the situation goes beyond their range of tolerance set by the genetic organisation as the factors may become critical at different stages of the life-cycle. The species around provide the genetic material for recruitment and ecesis within the community.pt. II Migration of species involving mobility of disseminules, their germination, aggregation, competition and final ecesis-ever continuing processes lead to colonisation and invasions. All these plant phenomena react upon the environment introducing changes therein. Thus newer community-environment-complex equilibria are set up in the dynamic system. The whole process is called, succession in relation to time and the series of succeeding communities for a given area, a sere. When it happens ‘de novo’ with no trace of plant present originally in the area, it is prisere as a result of primary succession and subsere with disturbed communities in which secondary succession is the rule. The mechanism of succession is driven by the reacting and changing environment consequential largely either to the plant processes themselves or to extraneous forces succession is autogenic in the former and allogenic in the latter case. In every case succession terminates into a more stable climax community generally dependant upon the climate and soil. The taxa used for classifying communities differ widely among ecologists but association is the basic unit accepted by all, though with varying concepts. The concept of ecosystem in relation to energy and matter within the community is the most acceptable basis for comprehending;vegetation types in India.Pt. III Since vegetation evolves out of the flora floristic regions of India should form the basis of its main divisions. For this purpose three main latitudinal belts viz. (1) Eastern and Western Himalayas, (2) Assam, Gangetic Plains and Rajasthan, and (3) Deccan and Malabar are recognised. The seven provinces with their distinct climate including photoperiod can be individually considered for the description of vegetation types along gradients of altitude, humidity-aridity, history and proximity of human settlements and soil fertility. Along these gradients closed, open and desert types of structure within forests, scrub and grass can be described with their combinations wherever necessary. Physiognomy, structure, function, composition, dynamics, habitat relations and history are the important diagnostic criteria of vegetation types. Size, texture and seasonal behaviour of leaves of dominant species may also be given. The hydrophytes can be described in each place as floating, suspended, submerged anchored, floating-leaved anchored and emergent anchored.

Multitemporal Field-Based Maize Plant Height Information Extraction and Verification Using Solid-State LiDAR

Plant height is regarded as a key indicator that is crucial for assessing the crop growth status and predicting yield. In this study, an advanced method based on solid-state LiDAR technology is proposed, which is specifically designed to accurately capture the phenotypic characteristics of plant height during the maize growth cycle. By segmenting the scanned point cloud of maize, detailed point cloud data of a single maize plant were successfully extracted, from which stem information was accurately measured to obtain accurate plant height information. In this study, we will concentrate on the analysis of individual maize plants. Leveraging the advantages of solid-state LiDAR technology in precisely capturing phenotypic information, the data processing approach for individual maize plants, as compared to an entire maize community, will better restore the maize’s original growth patterns. This will enable the acquisition of more accurate maize plant height information and more clearly demonstrate the potential of solid-state LiDAR in capturing detailed phenotypic information. To enhance the universality of the research findings, this study meticulously selected key growth stages of maize for data validation and comparison, encompassing the tasseling, silking, and maturity phases. At these crucial stages, 20 maize plants at the tasseling stage, 40 at the flowering stage, and 40 at the maturity stage were randomly selected, totaling 100 samples for analysis. Each sample not only included actual measurement values but also included plant height information extracted using point cloud technology. The observation period was set from 20 June to 20 September 2021. This period encompasses the three key growth stages of maize described above, and each growth stage included one round of data collection, with three rounds of data collection each, each spaced about a week apart, for a total of nine data collections. To ensure the accuracy and reliability of the data, all collections were performed at noon when the natural wind speed was controlled within the range of 0 to 1.5 m/s and the weather was clear. The findings demonstrate that the root mean square error (RMSE) of the maize plant height data, procured through LiDAR technology, stands at 1.27 cm, the mean absolute percentage error (MAPE) hovers around 0.77%, and the peak R2 value attained is 0.99. These metrics collectively attest to the method’s ongoing high efficiency and precision in capturing the plant height information. In the comparative study of different stem growth stages, especially at the maturity stage, the MAPE of the plant height was reduced to 0.57%, which is a significant improvement compared to the performance at the nodulation and sprouting stage. These results effectively demonstrate that the maize phenotypic information extraction method based on solid-state LiDAR technology is not only highly accurate and effective but is also effective on individual plants, which provides a reliable reference for applying the technique to a wider range of plant populations and extending it to the whole farmland.

Effect of Varieties and Dates of Sowing on Seed Yield of Sunhemp

A field experiment was conducted at Agricultural Research Stattion, Amadalavalasa to identify a suitable sunhemp variety and sowing window during Khariff or obtaining higher yields in North Coastal Andhra Pradesh. The soil of experimental site was sandy loam in texture, medium in alkaline reaction (pH: 8.24), non-saline (EC: 0.22 dS m-1), low in organic carbon (0.5%), low in available nitrogen (219.3 kg ha-1), low in available phosphorus (22.18 kg P2O5 ha-1) and medium in available potassium (268.3 kg K2O ha-1). The experiment was laid out in a split plot design with four main plot treatments, three subplot treatments and with three replications. The main treatments comprised of four dates of sowing viz., D1: 1st may,D2:15th may,D3:1st june and D4: 15th june. The sub plot treatments comprised of three varieties viz., V1: K12 yellow, V2: K12 black and V3: SH 4. All the cultural practices were adopted as per the recommendations of University. The results of the experiment indicated that growth and yield of sunhemp was significantly influenced by variety as well as date of sowing. It was evident that sowing of sunhemp in North Coastal AndhraPradesh on 15th June was optimum as it recorded shorter plant height (224.8 cm), early flowering i.e flower initiation at 80 days, 50% flowering in 91 days, higher plant population and significantly higher seed yield (2.35 q/ha) was recorded. Among the varieties tested SH 4 produced taller plants exhibited early flowering and finally recorded significantly higher seed yield (2.16 q/ha). However, plant population did not vary significantly among the varieties. Interaction between dates of sowing and varieties indicated that for seed crop K12 black and SH 4 of sunhemp can be sown between 1st june to 15th June in North Coastal Andhra Pradesh for getting higher seed yield of sunhemp as the seed yield of the above two varieties and dates of sowing were atpar.