Phases Of Plant Growth Research Articles

Controlled release fertilizer: A review on developments, applications and potential in agriculture

Controlled release fertilizer (CRF) plays a crucial yet necessary part in the sustainable agriculture industry. An alarming rise in call for crop production directly influences the increasing need for synthetically derived fertilizers and pesticides production. The application of CRF has been a gamechanger as an environmentally sustainable pathway to increase crop yields by paving desired phase of plant growth via a direct or indirect mechanism. The mechanism of CRF does not only decreases nutrient dissipation due to volatilization and leaching, but also provides a precisely appropriate nutrient release design that is suitable in the physiological and biochemical aspect of the plant growth. However, CRF is not deployed on larger scale of commercial agriculture practices due to being expensive, has relatively low efficiency in releasing nutrients and its coatings are largely composed of petroleum-based synthetic polymers. Alternatively, there are many polymers derived from renewable and biodegradable sources that can be used as coating material for CRF in the form of bio-nanocomposites. Having said that, there is an apparent gap between the mechanism of the CRFs for promoting plant growth and the prominent role of the nanocomposites especially bio-nanocomposites as coating material for CRF synthesis, thus the importance of nanotechnology application in enhancing the effectiveness of CRF. Therefore, this review attempts to bridge the stated gap and summarizes the comprehensive developments, application mechanisms and future potential of CRF as a fertilizer for crop sustainability.

Eligibility criteria for joint ensilage of maize and yellow lupine on poorly productive lands of the Upper Volga region

In the modern conditions of RF agro-industrial complex development, the transfer of animal husbandry to an industrial basis is possible only with high-grade vegetable protein production increase. Silage of the aboveground mass of pure corn during all phases of plant growth and development does not provide the content of nutrients in the feed unit according to the zootechnical requirements. Therefore, to optimize the finished feed in terms of the carbohydrate-protein ratio, green mass of legumes should be added to its composition during the preparation of silage from corn. The selection of the legume component should be carried out taking into account the following main criteria: coincidence with corn by the growing season duration, the same attitude to soil and climatic resources and insolation conditions, high provision of the legume component with digestible protein, dry matter, starch and exchange energy during the ensiling period. It has been established that the joint ensiling of corn with yellow lupine is expedient when the corn is in waxy ripeness, and the lupine is in the phase of shiny beans with the component ratio of 55:45%. In this case, the content of digestible protein in 1 feed unit of finished silage is 100.2 g at reliable feed supply with both irreplaceable (36.0 g) and critical (7.2 g) amino acids.

A reevaluation of the role of the ASIL trihelix transcription factors as repressors of the seed maturation program.

Developmental transitions are typically tightly controlled at the transcriptional level. Two of these transitions involve the induction of the embryo maturation program midway through seed development and its repression during the vegetative phase of plant growth. Very little is known about the factors responsible for this regulation during early embryogenesis, and only a couple of transcription factors have been characterized as repressors during the postgerminative phase. Arabidopsis 6b‐INTERACTING PROTEIN‐LIKE1 (ASIL1), a trihelix transcription factor, has been proposed to repress maturation both embryonically and postembryonically. Preliminary data also suggested that its closest paralog, ASIL2, might play a role as well. We used a transcriptomic approach, coupled with phenotypical observations, to test the hypothesis that ASIL1 and ASIL2 redundantly turn off maturation during both phases of growth. Our results indicate that, contrary to what was previously published, neither of the ASIL genes plays a role in the regulation of maturation, at any point during plant development. Analyses of gene ontology (GO)‐enriched terms and published transcriptomic datasets suggest that these genes might be involved in responses during the vegetative phase to certain biotic and abiotic stresses.

Heritable variation in tree growth and needle vegetation indices of slash pine (Pinus elliottii) using unmanned aerial vehicles (UAVs)

Vegetation indices (VIs) are mainly associated with plant yield, and yield-related physiological traits can assist in breeding selection. Tree breeding programs require a rapid assessment of a large number of individual trees across multiple regions. Unmanned aerial vehicle (UAV) multispectral platforms combined with high spatial, temporal and spectral resolutions can readily assess the VIs at various plant growth phases, which has been deeply detailed for evaluating the physiological status of agricultural crops and forest stands. However, the underlying genetics of foliar spectral bands, VIs and growth traits from a large scale of samples, especially in the case of forest trees, have been less investigated. In this paper, two sites of slash pine breeding populations were completely investigated to monitor the spectral bands, VIs, and tree growth traits. This allows us to determine the genotypic variation of these traits and to estimate the heritability (h2). The results show that the estimated h2 ranges from 0.04 to 0.36, and the site may affect tree growth because the traits between two sites come to different h2 values. At the two sites, the h2 values of the green red difference vegetation index (GNDVI) and anthocyanin reflectance index (ARI) at Site 1 and the red edge chlorophyll index (RECI), leaf chlorophyll index (LCI), red green blue vegetation index (RGBVI), normalized difference red edge index (NDRE), NIR and red edge at Site 2 were less than 0.1. However, breeding selection is still possible for most VIs and growth traits at both sites based on different breeding targets and families (families 3, 5, 10, 11, 14 and 17 at Site 1 and 4, 6, 8, 19 and 13 at Site 2 for optimal spectral bands; families 2, 8, 7, 13, 16, and 18 at Site 1 and 6, 7, 11, 14, 15, 18, and 20 at Site 2 for optimal VIs; families 8 and 16 at Site 1 and families 7 and 18 at Site 2 for optimal growth traits) with a variety of optimal traits are selected. This paper demonstrates the potential use of UAV-based imagery technologies in the breeding selection of slash pine trees.

Exogenously Applied Proline Modulates Drought Tolerance in Maize (Zea mays L)

Improving drought stress tolerance in maize is essential to increase its production and yield worldwide. Thus, the present study was conducted to investigate the improvement of drought tolerance in maize (Zea mays L.) by exogenous application of proline (25 and 50mM) on two maize varieties. Maize plants were subjected to drought stress at various phases of plant growth under pot culture conditions and proline was applied as foliar spray. Water deficit stress caused a significant decrease (by approximately 25%) in growth and yield of both maize varieties by decreasing plant height, cob length, dry root weight, grains per cob and 100-grain weight. Water deficit stress also decreased chlorophyll and intercellular proline contents, and antioxidant enzyme activities viz. catalase (CAT), guaiacol peroxidase (POX) and ascorbate peroxidase (APX). Exogenous application of proline (50 mM) was found to be more effective in increasing growth and yield of both varieties. These increases were positively associated with increased levels (by at least 15%) of chlorophyll and intracellular proline, and enhanced activities of CAT, POX and APX enzymes in both varieties. Interaction effects of exogenous proline and water deficit stress were significant in aspects of higher growth and yields and enhanced levels of chlorophyll, intracellular proline and antioxidant enzyme activities. Therefore, it is concluded that foliar application of proline improves drought tolerance by modulating chlorophyll and intracellular proline contents, and antioxidant enzyme activities.

Influence of various types of absorbent and mulching materials on the productivity and quality of the harvest of cucumbers in the Forest-steppe of Ukraine

The article presents three year’s data on the influence of various types of absorbent and mulching materials on the productivity of Bettina hybrid cucumber for growing plants on a vertical trellis in the Forest-steppe conditions of Ukraine. The data on the passage of the main phenological phases of growth and development of cucumber plants, biometric parameters, yield and biochemical composition of fruits, correlation and variance analysis of the research results are presented. It was found that all phases of plant growth and development passed faster when the soil was mulched with black plastic wrap and black agro fbre using different types of absorbent. In comparison with the control, water-retaining granules and gel, against the background of the use of mulching materials, contributed to an increase in the height of the main stem, the formation of a larger number of leaves on the plant and the area of their assimilation surface. Among the mulching materials, the best results were obtained with the black flm, and among the types of absorbent - with the gel. The highest marketable yield was obtained from the options for mulching the soil with black plastic wrap using water-retaining granules and gel – 56,4 t/ha and 56,9 t/ha, respectively. The largest mass of the early harvest was provided by the option of mulching with a black flm and applying gel to the soil – 35,9 t/ha. Mulching materials and various types of absorbent have contributed to the increase in the marketability of the crop. However, the largest marketability was in the option of mulching with black flm and the use of water-containing granules – 99,4 %. Under the influence of mulching materials and various types of absorbent, the biochemical composition of cucumber fruits changed. The highest dry matter content was for mulching with black flm and the use of an absorbent – 5,3 %. The most sugary fruits were those with the option of mulching with a flm and using an absorbent in the form of a gel – 2,19 %. The content of nitrates in fruits did not exceed the maximum permissible level. However, their lowest content in fruits was under agro fbre without the use of an absorbent – 52,0 mg/kg. Key words: cucumber, hybrid, vertical trellis, absorbents, mulching materials, biometric indicators, yield, fruit marketability, crop quality.

Impact of fertigation schema on yield and chemical composition of strawberry (Fragaria×ananassa Duch.)

A frequent fertigation of garden strawberry with solute mineral fertiliser in accord with the plant growth phase allows a more efficient mineral nutrient absorption compared to a single application of larger fertiliser amount. Field studies on medium loam-granulometry sod-podzol soil in fruiting garden strawberry plantations were carried out for three years in the Moscow Region to evaluate the impact of fertigation regimes on strawberry yield and the main nutrient content in soil and plant leaves. In study setup, the control crop grew with a no-fertiliser drip irrigation, schema 1 included frequent (once in 3 days) mineral fertiliser drip application at 2-3 g/l, schema 2 — 4-6 g/l solution application twice less often (once in 6 days). Materials and methods. Yield was estimated by weight per plot area unit, plant samples analysed with conventional wet ashing. Nitrate nitrogen was determined in ionometry, exchangeable ammonium — in photocolourimetry, mobile phosphorus and potassium specimens — by the Kirsanov’s CINAO-modified method. The article presents registration data, averaged leaf chemical assays and content dynamics of major soil macronutrients over a three-year observation period. Conclusions. A significant increase in three-year total yield was observed with the mineral fertiliser fertigation schema in the Ducat strawberry cultivar; a supraoptimal phosphorus accumulation in leaves of the Rusich cultivar was facilitated by a less frequent application of concentrated fertiliser solution; a maximal nitrogen amount in Ducat leaves was observed with fractional fertigation; in a lower-yield season, concentrated mineral fertiliser fertigation contributed to the increase of mobile phosphorus and potassium specimens in soil in mid growing season. A greater correlation was observed between the soil content of mobile potassium and its uptake by strawberry plants.

Soil erosion dynamics on a cultivated slope in the Western Polish Carpathians based on over 30 years of plot studies

Soil erosion is one of the most important processes affecting land degradation, especially in mountainous areas. The main aim of this study was to assess the dynamics of surface runoff and soil erosion in the Carpathians (Poland), based on data from over 30 years of plot studies, determine the threshold of extreme soil erosion on agricultural slopes, and estimate the cover-management factor (C-factor) of the flysch mountains. The field research was carried out in the Bystrzanka catchment on experimental plots with potato, cereals and grassland crop. The average annual soil erosion on the potato plots was 25.67 Mg ha−1 year−1, which was 95.4 and 99.7% higher than the soil erosion on the cereal and grassland plots. Principal component analysis was used to identify the factors determining soil erosion in the Carpathians, taking into account precipitation parameters, soil conditions, plant growth phases and agricultural practices. There were positive statistically significant relationships (p < 0.05) between soil erosion and precipitation sum and surface runoff. Precipitation thresholds for soil erosion of various magnitudes were determined, and the extreme soil erosion threshold was calculated (8.79 Mg ha−1 for a single soil erosion event and 59.37 Mg ha−1 for the annual total soil erosion). In addition, the Revised Universal Soil Loss Equation was used to show the role of the C-factor (calculated based on long-term plot studies, and proposed for Poland in the literature) in soil erosion studies. Different C-factors reflect changes in average soil erosion of up to 69%. Long-term plot studies are key to agricultural production and sustainable development in mountainous areas.

Morpho-Physiological Classification of Italian Tomato Cultivars (Solanum lycopersicum L.) According to Drought Tolerance during Vegetative and Reproductive Growth.

Irrigation is fundamental for agriculture but, as climate change becomes more persistent, there is a need to conserve water and use it more efficiently. It is therefore crucial to identify cultivars that can tolerate drought. For economically relevant crops, such as tomatoes, this purpose takes on an even more incisive role and local agrobiodiversity is a large genetic reservoir of promising cultivars. In this study, nine local Italian cultivars of tomatoes plus four widely used commercial cultivars were considered. These experienced about 20 d of drought, either at vegetative or reproductive phase. Various physio-morphological parameters were monitored, such as stomatal conductance (gs), photosynthesis (A), water use efficiency (WUE), growth (GI) and soil water content (SWC). The different responses and behaviors allowed to divide the cultivars into three groups: tolerant, susceptible, and intermediate. The classification was also confirmed by a principal component analysis (PCA). The study, in addition to deepening the knowledge of local Italian tomato cultivars, reveals how some cultivars perform better under stress condition than commercial ones. Moreover, the different behavior depends on the genotype and on the growth phase of plants. In fact, the Perina cultivar is the most tolerant during vegetative growth while the Quarantino cultivar is mostly tolerant at reproductive stage. The results suggest that selection of cultivars could lead to a more sustainable agriculture and less wasteful irrigation plans.

Biometric responses of sugarcane under high doses of vinasse

ABSTRACT Rational use of vinasse as a fertilizer in sugarcane cultivation is a good option to increase crop development and yield due to its nutritional support, properly dispose of the by-product, and reduce costs of mineral nutrition. However, in the field, controlling the amount of vinasse can be difficult, interfering in sugarcane development. In this sense, this study aimed to evaluate high doses of vinasse related to biometric responses in the initial growth phase of sugarcane plants. The experimental design was completely randomized, and the treatments consisted of five vinasse doses (0, 150, 300, 600, and 1200 m3 ha-1), with six replicates, except D0, three replicates, and one dose of mineral fertilizer with 70 kg ha-1 of N, 120 kg ha-1 of P2O5 and 90 kg ha-1 of K2O, with three replications. The biometric variables were evaluated in the following sequence: number of tillers per pot from 60 to 150 days after planting (DAP), plant height, number of green and dry leaves from 90 to 210 DAP, stem diameter, leaf area, and fresh and dry biomasses of roots and shoots at 210 DAP. Vinasse increased the biomass production through the number of tillers and the number of leaves compared to mineral fertilizer, promoting greater growth up to the dose of 600 m3 ha-1. The vinasse dose of 1200 m3 ha-1 decreased the plant height.

Can We Estimate Functionality of Soil Microbial Communities from Structure-Derived Predictions? A Reality Test in Agricultural Soils.

ABSTRACTComputational approaches that link bacterial 16S rRNA gene amplicon data to functional genes based on prokaryotic reference genomes have emerged. This study aims to validate or refute the applicability of the functional gene prediction tools for assessment and comparison of community functionality among experimental treatments, inducing either fast or slow responses in rhizosphere microbial community composition and function. Rhizosphere samples of wheat and barley were collected in two consecutive years at active and mature growth phases from organic and conventional farming plots with ambient or future-climate treatments of the Global Change Experimental Facility. Bacterial community composition was determined by 16S rRNA gene amplicon sequencing, and the activities of five extracellular enzymes involved in carbon (β-glucosidases, cellobiohydrolase, and xylosidase), nitrogen (N-acetylglucosaminidase), and phosphorus (acid phosphatase) cycles were determined. Structural community data were used to predict functional patterns of the rhizosphere communities using Tax4Fun and PanFP. Subsequently, the predictions were compared with the measured activities. Despite the fact that different treatments mainly drove either community composition (plant growth phase) or measured enzyme activities (farming system), the predictions mirrored patterns in the treatments in a qualitative but not quantitative way. Most of the discrepancies between measured and predicted values resulted from plant growth stages (fast community response), followed by farming management and climate (slower community response). Thus, our results suggest the applicability of the prediction tools for comparative investigations of soil community functionality in less-dynamic environmental systems.IMPORTANCE Linking soil microbial community structure to its functionality, which is important for maintaining health and services of an ecosystem, is still challenging. Besides great advances in structural community analysis, functional equivalents, such as metagenomics and metatranscriptomics, are still time and cost intensive. Recent computational approaches (Tax4Fun and PanFP) aim to predict functions from structural community data based on reference genomes. Although the usability of these tools has been confirmed with metagenomic data, a comparison between predicted and measured functions is so far missing. Thus, this study comprises an expansive reality test on the performance of these tools under different environmental conditions, including relevant global change factors (land use and climate). The work provides a valuable validation of the applicability of the prediction tools for comparison of soil community functions across different sufficiently established soil ecosystems and suggest their usability to unravel the broad spectrum of functions provided by a given community structure.

ОСОБЛИВОСТІ ВЕГЕТАЦІЇ АГРОФІТОЦЕНОЗІВ ПШЕНИЦІ ОЗИМОЇ ПІСЛЯ ПОПЕРЕДНИКІВ БОБОВИХ БАГАТОРІЧНИХ ТРАВ

The article is devoted to solving the problem of increasing the yield of winter wheat crops when it is grown after the predecessors of six types of perennial legumes. The features of the passage of the growth and development phases of winter wheat plants in the spring are shown, depending on the predecessors. The dynamics of plant height in the spring-summer period is analyzed. The change in the density of winter wheat plants during the spring renewal of the growing season and at the end of the growing season was studied. The spring thinning of winter wheat plants, the coefficient of total and productive tillering are calculated. The total number of stems of winter wheat plants and productive stems is shown. The level of grain yield of winter wheat, depending on its predecessors, was investigated, and correlation-regression relationships between it and the factors of spring-summer vegetation of crops were revealed. A close correlation has been proved between the grain yield and the number of all stems, as well as productive stems of winter wheat plants on an area of one square meter, as well as between the grain yield and the height of winter wheat plants at the beginning of spring regrowth. It is shown that the most favorable growing conditions and the level of grain yield of winter wheat when growing it after various types of perennial legumes is observed after the predecessor of meadow clover, where the highest plant density at the end of the growing season was observed – 145 million pcs/ha, the number of total – 878 pcs./m2 and productive stems – 799 pcs./m2, as well as the highest plant height at the beginning of spring regrowth – 6 cm. This allows you to get a winter wheat grain yield of 5.8 t/ha without the use of mineral fertilizers. After white melilot, the yield of winter wheat was 10.2 % less and amounted to 5.21 t/ha; after sandy sainfoin – 14.% less – 4.99 t/ha; after the eastern goat's rue – by 21.6 % less – 4.55 t/ha; after sowing alfalfa – by 24.5 % less – 4.38 t/ha and after horned grass – the lowest yield – 4.03 t/ha, which is 30.6 % less than after meadow clover

Application of Potassium Fertilizer and Chicken Coop Fertilizer Against Growth and Production of Shallots (Allium ascalanicum L.)

This study aims to determine the application of potassium fertilizer and chicken manure to the growth and production of shallots (Allium ascalanicum L.). The study used a randomized block design with 2 factors repeated 3 times. Factor 1: Potassium Fertilizer 40,60,80 kg/ha. Factor 2: Chicken Manure 5,10,15 tons/ha. The results showed that the application of potassium fertilizer and chicken manure did not interact with either the growth phase or the production phase of the plant on all observation variables, while the potassium fertilizer treatment showed significantly different results only on the plant vegetative growth parameters, namely the number of leaves at the age of 7 days after planting, namely ( 8,111 strands), while the vegetative phase had no significant effect on the number of tubers per clump, wet weight of tubers per clump, wet weight of tubers per plot, dry weight of sun-dried tubers per clump, and dry weight of sun-dried tubers per plot. While the treatment of chicken manure had a significant effect on the vegetative growth phase of plants, namely the length of plants at 28 DAP (30.278 cm) and 35 DAP (32.704 cm), on the number of leaves at 7 DAP (8,000 strands). While the generative phase (60 DAP) significantly affected the number of tubers per clump, namely (5,889 grams), wet weight of tubers per clump (38,333 grams), wet weight of tubers per plot (319,000 grams), dry weight of sun-dried tubers per clump. namely (23.074 grams), and the dry weight of sun-dried tubers per plot (191.889 grams).

Estimating water requirements of tomato plant based on Forecast-Evapotranspiration Equation in Semangat Village, Merdeka Sub-district, Karo Regency, North Sumatera Province, Indonesia

Tomato plant is one of the horticulture products that produce in Semangat Village. One of the problems focused by tomato’s farmer was how much water will give. Estimating water requirements for tomato plants will make it easier for farmers to provide water according to the phase of plant growth. The aims of the research was to estimating water requirements of tomato plants in Semangat Village Merdeka District, Karo Residence. The methods divided two steps, they were analysis the forecast-potential evapotranspiration, and estimating water requirements of tomato plant where calculated by the relation of crop coefficient and forecast-potential evapotranspiration. The results showed forecast-potential evapotranspiration (ETo) in Semangat Village were 3.36 – 6.89 mm/day during January until July, 2020. The water requirements of tomato plant showed 3.141 mm/day in the early phase, 6.02 mm/day in the middle phase, and 4.188 mm/day in the final phase. The conclusion showed that the water requirement of tomato plants for all of growth phase was increase as high as crop coefficient of tomato plants.

Irrigation Management Strategies with Brackish Water in Production and Post-harvest Quality of “Toad Skin” Melon

In regions with water scarcity, it is necessary to use well water, often brackish water, in the irrigation of crops, which requires the adoption of management mitigation strategies. This study was carried out in the Fazenda Pedra Preta, Mossoro, Brazil, with the objective of evaluating the use of 10 management strategies of irrigation with two types of water (electrical conductivity ECWP1 = 0.57 dS m−1 and ECWP2 = 4.33 dS m−1). This was based on alternating and/or varied application as a function of the phenological stage during the plant growth phase, on the production, mean weight, and quality of the “Toad Skin” melons (Cucumis melo L., cv Sancho). A randomized complete block design with four replications was used, totaling 40 experimental plots. It was concluded that irrigation with water of electrical conductivity of 0.57 dS m−1 in the flowering and fruiting phases and water of 4.33 dS m−1 in the vegetative growth and maturation phases has produced more commercial fruits with higher mean weight. Through time, water management strategies did not influence the number of fruits per plant, fruit productivity, soluble solids content, and pulp firmness.

Heat stress response mechanisms in pollen development.

SummaryBeing rooted in place, plants are faced with the challenge of responding to unfavourable local conditions. One such condition, heat stress, contributes massively to crop losses globally. Heatwaves are predicted to increase, and it is of vital importance to generate crops that are tolerant to not only heat stress but also to several other abiotic stresses (e.g. drought stress, salinity stress) to ensure that global food security is protected. A better understanding of the molecular mechanisms that underlie the temperature stress response in pollen will be a significant step towards developing effective breeding strategies for high and stable production in crop plants. While most studies have focused on the vegetative phase of plant growth to understand heat stress tolerance, it is the reproductive phase that requires more attention as it is more sensitive to elevated temperatures. Every phase of reproductive development is affected by environmental challenges, including pollen and ovule development, pollen tube growth, male–female cross‐talk, fertilization, and embryo development. In this review we summarize how pollen is affected by heat stress and the molecular mechanisms employed during the stress period, as revealed by classical and ‐omics experiments.

Current Understanding of Leaf Senescence in Rice.

Leaf senescence, which is the last developmental phase of plant growth, is controlled by multiple genetic and environmental factors. Leaf yellowing is a visual indicator of senescence due to the loss of the green pigment chlorophyll. During senescence, the methodical disassembly of macromolecules occurs, facilitating nutrient recycling and translocation from the sink to the source organs, which is critical for plant fitness and productivity. Leaf senescence is a complex and tightly regulated process, with coordinated actions of multiple pathways, responding to a sophisticated integration of leaf age and various environmental signals. Many studies have been carried out to understand the leaf senescence-associated molecular mechanisms including the chlorophyll breakdown, phytohormonal and transcriptional regulation, interaction with environmental signals, and associated metabolic changes. The metabolic reprogramming and nutrient recycling occurring during leaf senescence highlight the fundamental role of this developmental stage for the nutrient economy at the whole plant level. The strong impact of the senescence-associated nutrient remobilization on cereal productivity and grain quality is of interest in many breeding programs. This review summarizes our current knowledge in rice on (i) the actors of chlorophyll degradation, (ii) the identification of stay-green genotypes, (iii) the identification of transcription factors involved in the regulation of leaf senescence, (iv) the roles of leaf-senescence-associated nitrogen enzymes on plant performance, and (v) stress-induced senescence. Compiling the different advances obtained on rice leaf senescence will provide a framework for future rice breeding strategies to improve grain yield.

Effect of Seedbed Types and time of Vine Harvesting on Shoot and Tuber Yields of Sweet Potato [Ipomoea batatas (L.) Lam.] in South-south, Nigeria

A field experiment was conducted at Rivers Institute of Agricultural Research and Training (RIART), Rivers State University, Port Harcourt, Nigeria with the objective of evaluating the influence of seedbed types and vine harvesting time on shoot and tuber yields of sweet potato and make recommendations for optimal and sustainable production. The treatments consisted of three seedbed types (ridge, flat, and mound), and four vine harvesting time (8, 12, 16 and 20 weeks after planting). The experiment was laid out as a 3 x 4 in factorial arrangement fitted into a randomized complete block design (RCBD) and replicated three times. The results revealed that planting of sweet potato on ridge produced the highest root tuber yield followed by mound seedbeds; planting on flat seedbed produced the highest shoot (vine) and lowest tuber yields. While planting on ridge seedbed and harvesting the vines 16 weeks after planting (when about 80% of the growth phase of the plant was completed) produced optimum shoot yield which could be used as fodder with no significant effect on root tuber yield. In general, vine harvesting during active growth phase of the sweet potato plant seriously depressed tuber yield more than it affected shoot production. These results therefore stand as our recommendations for sweet potato production in the South-south zone of Nigeria.

Comparative assessment of the work of photosystem II in the leaves of soybean varieties and hybrids

The efficiency of PS II of soybean leaves was shown depending on the genotype of the variety, the phase of plant growth and development, and the intensity of their illumination in the field. Purpose of the work: to study the intensity of photosynthetic processes in soybean leaves using a MINI-PAM fluorometer to isolate highly active ones. The object of research was early maturing and mid-maturing varieties, white-flowered soybean hybrids. The efficiency of PS II (Y) with a sequential increase in the illumination intensity was determined in the early ripening variety Sonata and the mid-ripening Oktyabr 70. The most stable efficiency of PS II was in the leaves of the varieties Sonata and Oktyabr 70 at an illumination degree of ≈ 800 to 1500 μmol quanta m-2 s-1. The Sonata cultivar had a higher potential in the restoration of the photochemical activity of PS II. The dependence of PS II activity on the phase of plant growth and development was revealed. A high level of effective quantum yield of PS II (0.84 … 0.86 rel. units) during the growing season was noted in the leaves of new soybean varieties Kruzhevnitsa, Evgeniya, Persona and Kitrossa. Plants of the white-flowered collection had the maximum parameters of the quantum yield of PS II during the period of formation of reproductive organs. The data obtained allowed us to recommend the varieties Sonata, Kruzhevnitsa, Evgeniya, Persona, and Kitrossa, as well as hybrids KB (5) and KB (26) for inclusion in the breeding process, as they have a high level of PS II work, when creating varieties with increased photosynthetic activity.

Shade stress in various growth phases of peanut genotypes and its effect on agronomic characters and chlorophyll content

Shading stress during plant growth is one of the factors that might decrease the peanut crop productivity. The growth phase of the peanut genotypes has different responses to shade stress. This research aimed to study the effect of shade stress in various growth phases on agronomic character and chlorophyll content of peanut genotypes. Shade stress was regulated in six conditions: no shade, shade from planting to harvest, shade from planting until 25 days after planting (dap) (vegetative phase), shade from 26 to 50 dap (flowering phase to pods formation), shade from 51 to 75 dap (seed filling phase), and shade from 75 to 100 dap (the ripening phase of the seeds to harvest). The shade was carried out using paranet which holds 35% of the sun’s rays. The genotypes used were F3 generation plants from crosses (G200-I and G300-II x cv.Domba, Takar 1, Bison). The results showed that there were no significant differences in the interactions between shades in various growth phases and genotypes for agronomic traits, but there were significantly different interactions on the content of chlorophyll-a and total chlorophyll. All 12 peanut genotypes tended to produce more chlorophyll-a and total chlorophyll in shade treatment from planting to harvest. Shade at various plant growth phases had a significant effect on agronomic characters. The shade given from planting beginning to harvest produced the lowest dry pod weight (12.9 g/plant) or yield decreased to 23.7% compared to peanut grown without shading. The genotypes significantly affected agronomic traits and g6 genotype (G200-I x cv.Domba)7 produced the heaviest dry pod weight 17.2 g/plant.