Seeding Rate Research Articles

Effect of biostimulants on mustard microgreens grown under different cultivation conditions

Ten products, commercially available as biostimulants or reported for their biostimulating properties, were tested under conventional and organic growing systems for their effects on mustard microgreens (Brassica juncea) grown in presence of abiotic (salt) or biotic (Pythium ultimum) stress. Drench application of wollastonite (calcium silicate) significantly improved the germination rate of mustard seeds sown in a substrate inoculated with P. ultimum in conventional growing system exclusively. In both growing systems, no significant effect of biostimulants was observed on the dry biomass or the proportion of healthy microgreens grown in presence of P. ultimum. None of the biostimulants significantly increased the germination rate of seeds exposed to a salinity stress in both growing systems while humic acid, triacontanol, chitosan, and Bacillus subtilis PTB185 significantly decreased the germination rate of seeds exposed to 40, 80 or 120 mM NaCl L-1 under conventional or organic management. Seed treatment with Trichoderma harzianum T-22 and humic acid resulted in microgreens with a significantly higher dry biomass when subjected to 40 and 80 mM NaCl L-1 under conventional and organic management, respectively. The study showed that the effects of the biostimulants vary from beneficial to detrimental and that plant response to biostimulants is influenced by the cultivation conditions.

Effect of Feeding Black Soldier Fly Larvae (Hermetia illucens Linnaeus, 1758) and Commercial Feed on the Growth Rate of Common Carp (Cyprinus carpio Linnaeus, 1758)

Feed is an important element in supporting the growth and survival of fish. Availability and quality of feed is a factor that determines the success of cultivation. So far, some fish farmers still rely on feed directly from nature, such as small fish and leaves. The price of commercial feed is currently very expensive, so the costs incurred for feed are felt by fish farmers. To reduce feed prices, looking for alternative protein sources that are cheaper and easier to obtain is necessary. Therefore, it must provide other alternatives such as natural feed whose availability does not depend on the season, for example Maggot or black soldier fly larvae (Hermetia illucens) which are alternative feeds because they meet the requirements as a source of protein. The purpose of this study was to determine the comparative effect of feeding maggot (Hermetia illucens) and commercial feed on the growth rate of common carp (Cyprinus carpio) seeds, as well as to find out the best feeding on the growth rate and survival of common carp seeds. This study used a Complete Randomized Design (CRD) with 5 treatments and 4 replications. The frequency of feeding is 2 times a day at 08.00 and 16.00 morning and evening as much as 5% of fish biomass. Weight, length, survival rate and water quality measurements were carried out every 7 days. The results of the study showed that the highest growth in length and weight was found in the P3 treatment with a combination of 25% commercial feed and 75% maggot, namely 9.33 cm and 10.23 grams, and a survival value of 90% -100%.

Research on the development of digital technologies and agriculture

The aim of the work is to study the coordination of the growth rates of the use of digital technologies in agricultural organizations and the efficiency of agricultural production in farms of all categories of the Russian Federation. Based on Rosstat data and our own calculations, the chain growth rates of indicators for 2019-2022 have been studied. With the growing number of organizations by type of activity, agriculture, forestry, hunting, fishing, fish farming in the Russian Federation, their costs for information and communication technologies, and for the purchase of telecommunications equipment are increasing. but they reduce the cost of purchasing software in the face of anti-Russian sanctions, a pandemic and shock effects. The instability of the development of organizations in the information infrastructure is associated with a decrease in the number of personal computers per 100 employees and the number of organizations using broadband Internet access. The coordination of the growth rate of potato, sugar beet, and sunflower seeds yields with the growth rate of organizations’ costs for the purchase of telecommunications equipment has been established. The dynamics of vegetable yields is coordinated with the dynamics of organizations’ expenditures on information and communication technologies.

Enhancing germination percentage and seed vigor in horticultural Crops through biopriming techniques

Seed biopriming induces a physiological condition that promotes germination and uniform seedling emergence. An investigation is carried out on different seeds such as carrot (Daucus carota subsp. Sativus), onion (Allium cepa L.), cauliflower (Brassica oleracea), radish, (Raphanus sativus), tomato (Solanum lycopersicum), spinach (Spinacia oleracea), fenugreek (Trigonella foenum-graecum), and pea (Pisum sativum) to standardise bio-priming with Bacillus siamensis strain NKIT-9 to improve seed germination and seedling vigor index. To optimise the concentration of bio-priming seedlings were bioprimed overnight with Bacillus siamensis strain (NKIT-9) at varied concentrations (0.1mg/ml, 10µg/ml, 0.1µg/ml, and 10ng/ml). Bio-priming with Bacillus siamensis strain NKIT-9 gave highest values of germination percentage and seedling vigor index of carrot (at 0.1mg/ml), onion (at 0.1µg/ml ), cauliflower at 0.1mg/ml, 10µg/ml, and 0.1µg/ml), radish (at0.1mg/ml and 0.1µg/ml), tomato (at 0.1mg/ml), spinach (at 10ng/ml ), fenugreek (at 10ng/ml) and pea (a10ng/ml ) as compared with control. carrot, onion, cauliflower, radish, tomato, spinach, fenugreek, and pea exhibited higher germination percentages (60%, 100%, 100%, 100%, 80%, 90%, 100%, and 60% respectively) and seedling vigor indexes (148 ,720, 910, 880, 525, 580, 990, and 1018 respectively) when compared with control. Therefore, bio-priming with these concentrations is best suited for improving germination rate and seedling vigor of seeds.

Bee Visits Improves Production Parameters of Maize in Northern Côte d’Ivoire (West Africa)

Maize (Zea mays) is one of cereal rich in nutrients and antioxidants essential for human health. Many studies showed that this speculation is pollinated indirectly by wind. However, we observed a strong presence of bees on the male flowers of maize as soon as they open. The high activity of bees on these flowers, causes an intense release of pollen, which couldimpact positively the fruit set. This study was carried out in the botanical garden of the university Peleforo Gon Coulibaly of Korhogo located in northern Cote d'Ivoire. Two varieties of maize (EV8728-SR and LG501) were used for this study. For each variety, 15 plants were protected from insect visits and 15 other plants were still unprotected. Ear mass,seed mass and seed number resulting from each treatment were analyzed. The findings showed that the average number of seeds per ear resulting from unprotected plants (V1: 445.8 ± 17.92 and V2: 442.27 ± 6.8) was significantly higher compared to the protected plants (V1: 242.13 ± 4.39 and V2: 208.6 ± 9.52) for each variety. The average mass of seeds resulting from unprotected plants (V1: 205.31 ± 2.23g and V2: 169.45 ± 5.15g) was also higher compared to the protected plants (V1: 101.79 ± 1.93g and V2: 77.49 ± 1.70g). Whatever the maize variety, the germination rate of seeds resulting from unprotected plants (V1: Tg = 96.67% and V2: Tg = 100%) was higher compared to the protected plants (V1: Tg = 66.67% and V2: Tg = 56.67%). This study are very relevant for farmers and scientists because, it showed clearly bee contribution in the maize production improvement.

Herbage Mass Productivity, Composition, and Biological Compatibility of Oat and Vetch Mixture at Different Seed Rate Proportions in Abandoned Lands

Herbage Mass Productivity, Composition, and Biological Compatibility of Oat and Vetch Mixture at Different Seed Rate Proportions in Abandoned Lands

Pengaruh Pemberian Ekstrak Buah Belimbing Wuluh (Averrhoa Bilimbi) Sebagai Suplemen Dalam Pakan Buatan Untuk Meningkatkan Pertumbuhan Dan Kelangsungan Hidup Benih Ikan Nila Gift (Oreochromis Niloticus)

Gift tilapia is a fish that is widely favoured by people in Bengkulu province and includes fish that has important economic value. Efforts to increase the growth rate of gift tilapia is one idea to increase production. As an important source of protein for the community. Gift tilapia has the advantage of being easy to breed, fast growth rate, and can be cultivated intensively and extensively with high density. The survival rate of tilapia seeds is highly influenced by several factors of the aquatic environment such as temperature, pH and feed. The growth of tilapia seeds also depends on the quality of the feed given every day, the higher the nutritional value of the feed given, the growth rate will increase, so therefore the provision of belimbing wuluh juice is expected to help improve the growth system and resilience of gifted tilapia seeds. This research was conducted in April to May located in the yard of the orange alley house, in Karang Anyar II Village, Argamakmur District, North Bengkulu. This study used a completely randomised design with 4 treatments and 3 replicates, namely Treatment A (no extract 0 ml/kg pellets), B (star fruit extract 55 ml/kg pellets), C (star fruit extract 75 ml/kg pellets) and Treatment D (star fruit extract 95 ml/kg pellets). The results showed that the provision of star fruit extract in artificial feed had a very significant effect on the length growth of gift tilapia, and the weight growth of gift tilapia. The best survival of gift tilapia in treatment C (star fruit extract 75 ml/kg pellets) with a survival value of 100% and produced the highest length growth in treatment D of 15.12 cm and the highest absolute weight growth was in treatment D with a value of 16.6 grams.

Persilangan Ikan Nila (Oreochromis niloticus) Dari Berbagai Varietas Serta Ikan Mujahir (Oreochromis mossambicus) Untuk Mendapatkan Benih Bersifat Unggul

This research aims to produce seeds from the crossbreeding of nile tilapia (Oreochromis niloticus) of the jabir, nirwana, and sultana strains, as well as Mozambique tilapia (Oreochromis mossambicus). The crosses involved using male jabir nile tilapia with female nirwana nile tilapia and male mozambique tilapia with female sultana nile tilapia. The breeding was conducted in a 1:3 ratio of male to female. The spawning process occurred over a 16-day cycle, followed by a 28-day period of larval rearing. Crossbreeding between jabir and nirwana resulted in a higher spawning rate (17%) compared to the crossbreeding of mozambique and sultana (7%). The specific growth rate of seeds from the jabir and nirwana cross (14%) was not significantly different from the mozambique and sultana cross (13%). The survival rate of seeds from the jabir and nirwana cross (80%) was higher than from the mozambique and sultana cross (70%). Crossbreeding between male jabir nile tilapia and female nirwana nile tilapia exhibited better performance compared to the crossbreeding of male mozambique tilapia and female sultana nile tilapia.

The fertility tracks of pollen tube in the ovary of Solanum nigrum by three-dimensional reconstruction.

In this paper, we present an enhanced method for automatically capturing a large number of consecutive paraffin sections using a microscope. Leveraging these microstructural images, we employed three-dimensional visualisation and reconstruction techniques to investigate the dispersal growth process of pollen tube bundles upon entering the ovary of Solanum nigrum. Additionally, we explored their behaviour within different ovules and examined the relationship between the germination rate of seeds and the fertilisation process. Our findings reveal that despite the abundance of Solanum nigrum seeds, only a fraction of them is capable of successful germination. The germination rate of seeds is closely related to whether fertilisation of the ovules and pollen tubes is completed. Due to the limited number of pollen tubes entering the ovary, only a portion of the ovules can be fertilised. The proportion of fertilised ovules positively correlates with the germination rate of the seeds. Through three-dimensional reconstruction, we observed a phenomenon of proximity during the pollination process, wherein ovules closer to the pollen tube bundles are more likely to be fertilised. Furthermore, fertilised ovules exhibited significant changes in morphology and embryo sac structure. The number of fertilised ovules directly impacts the germination rate of wild Solanum nigrum seeds. Although all Solanum nigrum ovules have the potential to develop into seeds, most seeds originating from unfertilised ovules are unable to germinate normally, resulting in an incomplete germination rate of seeds and preventing it from reaching 100%.

Exogenous γ-Aminobutyric Acid Can Improve Seed Germination and Seedling Growth of Two Cotton Cultivars under Salt Stress.

Excessive salt content in soil has adverse effects on cotton production, especially during the germination and seedling stages. γ-aminobutyric acid (GABA) is an important active substance that is expected to improve the resistance of plants to abiotic stresses. This study focused on two cotton cultivars (Gossypium hirsutum L.: Tahe 2 and Xinluzhong 62) and investigated the impact of exogenous GABA (0, 1, 2, 3, and 4 mM) on seed germination, seedling growth, and related morphological, physiological, and biochemical indicators under salt stress (150 mM NaCl). The results showed that salt stress significantly reduced the germination rate and germination index of cotton seeds (decreased by 20.34% and 32.14% for Tahe 2 and Xinluzhong 62, respectively), leading to decreased seedling height and biomass and causing leaf yellowing. Salt stress induced osmotic stress in seedlings, resulting in ion imbalance (marked reduction in K+/Na+ ratio) and oxidative damage. Under salt stress conditions, exogenous GABA increased the germination rate (increased by 10.64~23.40% and 2.63~31.58% for Tahe 2 and Xinluzhong 62, respectively) and germination index of cotton seeds, as well as plant height and biomass. GABA treatment improved leaf yellowing. Exogenous GABA treatment increased the content of proline and soluble sugars, with varying effects on betaine. Exogenous GABA treatment reduced the Na+ content in seedlings, increased the K+ content, and increased the K+/Na+ ratio (increased by 20.44~28.08% and 29.54~76.33% for Tahe 2 and Xinluzhong 62, respectively). Exogenous GABA treatment enhanced the activities of superoxide dismutase and peroxidase, and reduced the accumulation of hydrogen peroxide and malondialdehyde, but had a negative impact on catalase activity. In conclusion, exogenous GABA effectively improved cotton seed germination. By regulating osmoprotectant levels, maintaining ion homeostasis, and alleviating oxidative stress, GABA mitigated the adverse effects of salt stress on cotton seedling growth.

Key Insights on Influences of Different Seed Rate and Phosphorus levels on growth and Productivity of Soybean (Glycine max l.): A Review

Key Insights on Influences of Different Seed Rate and Phosphorus levels on growth and Productivity of Soybean (Glycine max l.): A Review

Sunflower (Heliánthus ánnuus) Yield and Yield Components for Various Agricultural Practices (Sowing Date, Seeding Rate, Fertilization) for Steppe and Dry Steppe Growing Conditions

The dynamics of the productivity of the sunflower hybrid “Baiterek 17” were studied for rainfed conditions of the steppe and dry steppe zones of Kazakhstan for two fertilizer levels (without fertilizers and with the application of a nitrogen-phosphorous fertilizer), two sowing dates, and three seeding rates. The growing season duration varied among zones and was affected by sowing dates. An increase in duration (3–5 days) was observed for the early sowing date and fertilized treatments, regardless of the zone. Increasing the seeding rate for all treatments by sowing date and fertilizer application reduced the duration of the growing season by 3–6 days. The fertilizer application did not affect the formation of seedlings in the study areas. In the dry steppe zone, from 2.5 to 4.8 plants/m2 were formed before harvesting, with an increase in the number of plants at the high seeding rate (57,000 seeds/ha). In the steppe zone, the same pattern was preserved: from 3.5 to 4.9 plants/m2 at a seeding rate of 65 thousand seeds/ha. The maximum diameter and weight of the flower head were found for the early sowing date and fertilized treatments at a low seeding rate, with a strong effect on the yield for both the steppe and dry steppe zones in 2022. On average, for both years, the highest yield for the dry steppe zone was obtained for the sowing date of 15 May and at a seeding rate of 57,000 seeds/ha, while for the steppe zone, the highest yield was obtained for the 10 May planting date and at a sowing rate of 65,000 seeds/ha. Improving plant nutrition and increasing the plant density up to a seeding rate of 65,000 seeds/ha for the early sowing dates (10 May) increased the plasticity in the steppe zone. For the dry steppe zone, the plasticity of the hybrid decreased, but the highest plasticity was also obtained for an earlier sowing date (15 May) and at a seeding rate of 57,000 seeds/ha crop. The study shows that the hybrid “Baiterek 17” has a high ecological plasticity under changing environmental conditions and, with an increase in moisture availability, it requires intensive agricultural practices (fertilization, increased seeding rate, and early sowing dates) to obtain a high yield.

Seed Dormancy and Germination in Alfalfa (Medicago falcata L.)

Background: Medicago falcata L. (M. falcata L.) is widely distributed in Xinjiang and Inner Mongolia, which is a significant source of resistance genes. Its seeds have a high level of physical dormancy (PD). The current study aimed to study the dormancy characteristics, water absorption characteristics and methods for releasing hard seeds of M. falcata L., to reveal the the relationship between seed coat structure and water absorption and to understand the dormancy characteristics, which can provide theoretical basis for seed dormancy and seed biology research. Methods: Seed germination rate (GR), absorption, germination inhibitor activity and initial site of water entry into seeds were measured to investigate the causes of seed dormancy. Treatments to break dormancy included: (1) sandpaper sanding, (2) ultrasonic treatment for 30 min after sandpaper sanding, (3) 98% sulfuric acid immersion (5,10, 20, 40, 60 and 120 min) and (4) hot water immersion at different temperatures (50, 60, 70, 80 and 90oC) for 10 min, 20 min and 30 min. Result: The results showed that the hard rate of untreated seeds was 99.33% and the hard rate after the seed coat was scratched was 1.33%. Based on the inhibitory activity test of M. falcata L. seeds, high concentration seed extract has an inhibitory effect on the growth of other seeds. The toludine staining test showed that the hilum and microscope are the initial and main parts for seed water absorption. The germination rate of seeds after soaking in 98% sulfuric acid for 40 minutes and ultrasonic treatment with sandpaper for 30 minutes is higher than 94%, which is an effective method to relieve the PY of M. falcata L. seeds.

Crude Saponins from Chenopodium quinoa Willd. Reduce Fusarium Wilt Infection in Tomato Seedlings

Quinoa saponins are pentacyclic triterpene compounds composed of one triterpenoid glycoside and two different sugar chains. Previous studies have showed that natural quinoa saponins showed little or no antifungal activity, and there are few reports about their antifungal effects in recent decades. Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL) is the most serious for tomatoes in the field and under greenhouse conditions. The main objective of this study was to investigate the effectiveness of different concentrations and application modes of crude saponins from quinoa bran against the causal pathogen of tomato wilt under a greenhouse experiment. The results showed that the anti-FOL activity of quinoa saponins was weak in vitro, but significantly enhanced in vivo. Tomato seeds and seedlings treated with solution of quinoa saponins at 0.5 and 1.0 g/L significantly reduced the disease incidence (%) of tomato Fusarium wilt. The treatment types of saponin solution have influence on the preventive effects (%) of tomato seedlings against Fusarium wilt, among them, root soaking > foliar spray > seed soaking. The treatment of seed soaking with quinoa saponins inhibited germination of tomato seeds to some extent. However, the germination rate of tomato seeds after saponin soaking was comparable to the chemical pesticide (thiram carboxin); therefore, it could be used to control tomato wilt disease. This is due to the fact that the antifungal activity of quinoa saponins in vivo was much higher than that in vitro when the saponin concentration was between 0.5–1.0 g/L, indicating that the antifungal activity of quinoa saponins may be achieved mainly by inducing resistance. This investigation supports the potential use of quinoa saponins as a supplier of antifungal compounds, and could be the foundation for a future study examining the use of quinoa bran as a new resource against FOL.

Intercropping Forage Sorghum with Sunnhemp at Different Seeding Rates to Improve Forage Production

Forage sorghum (Sorghum bicolor (L.) Moench) is well established in the Texas High Plains as a drought-tolerant forage that often requires additional feed to provide adequate protein for livestock. Intercropping sunnhemp (Crotalaria juncea L.), a legume, with forage sorghum, may increase crude protein. However, the optimal intercrop seeding ratio of sunnhemp to sorghum to improve crude protein content and maintain sufficient biomass is unknown. A two-year field experiment was conducted near Canyon, TX, USA, in 2020 and 2021 using sunnhemp intercropped at three seeding rates (16.8, 33.6, and 50.4 kg ha−1) with forage sorghum at four seeding rates (0, 2.8, 5.6, and 11.2 kg ha−1) under drip irrigation. This study was conducted to (1) evaluate growth potential for sunnhemp in a semiarid environment, (2) find a seeding ratio that can maintain forage sorghum dry matter production and improve forage quality, and (3) determine if a midseason harvest can be supported and further improve quality of the forage produced. Midseason, full-season, regrowth biomass, and forage quality were evaluated. Results indicated that a sunnhemp–forage-sorghum intercrop produced dry matter comparable to forage sorghum when sufficient heat units were obtained in the growing season. Forage with higher nutritive value was produced when the intercrop was harvested twice.

Determination of Optimum Level of Seeding Rate of Silver Leaf Desmodim Intercropping with Desho Grass for Dry Matter Yield and Yield-Related Components in Western Ethiopia

Compatible production of forage grasses and legumes through intercropping is one of the best options to achieve higher biomass yield and forage quality for animal production in areas where land and other resources are scarce. This study was conducted in 2017 and 2018 with the aim of evaluating the best-match level of seeding rate of silverleaf desmodium (SLD) intercropped with desho grass (Pennisetum pedicellatum) in a randomized complete block design with three replications. The treatment consists of three levels of seeding rate of SLD (2, 4, and 6 kg ha−1) and one pure plot of each species. The result of this study showed that the intercropping of 6 kg ha−1 SLD with 100% of desho’s recommended plant population (50,000 plants ha−1) produced the highest forage dry matter yield and maximum plant height. The total dry matter yield (TDMY) of the intercrops was also significantly varied for the tested treatments. Accordingly, 6 kg ha−1 of SLD intercropped with 100% recommended seed rate of desho ha−1 gave the highest forage TDMY, which surpasses both the grass and legume yields in monoculture. The total land equivalent ratio (LER), which shows system productivity, was also different among the treatments. About 6 kg ha−1 of SLD intercropped with 100% recommended seed rate of desho also produced the highest LER (1.51). Thus, in Bako and similar agro-climatic conditions, where arable land is heavily covered with food crops, desho grass intercropping with SLD can be used as one of the best strategic options for producing feeds of energy and protein sources simultaneously on the same area of land.

Effects of Plant Regulators on the Seed Germination and Antioxidant Enzyme Activity of Cotton under Compound Salt Stress.

Salinity stress significantly hampers cotton seed germination and seedling growth. Employing plant growth regulators stands out as an effective strategy to mitigate salt stress. In this study, we assessed the impact of varying concentrations of natural composite salt conditions (0%, 0.6%, and 1.2%) on cotton seed germination, seedling growth, and physiology. Additionally, we explored the effects of compound sodium nitrophenolate (CSN: 2 mg·L-1 and 10 mg·L-1), 24-epibrassinolide (EBR: 0.02 mg·L-1 and 0.1 mg·L-1), and gibberellic acid (GA: 60 mg·L-1 and 300 mg·L-1), against a control (CK: distilled water) group. The results indicate that with an increase in the composite salt concentration, the germination potential (GP) and germination rate (GR) of cotton seeds gradually decrease. Simultaneously, the fresh weight and root vitality of seedlings also correspondingly decrease, while the degree of membrane lipid peroxidation increases. Under high-salt (1.2%) conditions, soaking treatments with CSN and EBR significantly enhance both GP (45-59% and 55-64%) and GR (30-33% and 39-36%) compared to the CK. However, the GA treatment does not increase the GP and GR of cotton. Moreover, under high-salt (1.2%) conditions, CSN and EBR treatments result in the increased activities of superoxide dismutase (56-66% and 71-80%), peroxidase (20-24% and 37-51%), and catalase (26-32% and 35-46%). Consequently, cotton exhibits a relatively good tolerance to natural composite salts. Soaking treatments with CSN and EBR effectively improve cotton germination by enhancing antioxidant enzyme activities, thereby strengthening cotton's tolerance to salt stress. These findings offer new insights for enhancing the salt tolerance of cotton.

Evaluation of the Potential Seed Dispersal Effectiveness of Malus sieversii (Lebed.) M. Roem. by Cattle

The success of plant reproduction is highly dependent on effective seed dispersal. This study aimed to evaluate the potential seed dispersal effectiveness of cattle for Malus sieversii. The impact of cattle on the dispersal quantity and dispersal quality of M. sieversii seeds was explored based on camera trapping, GPS tracking, and germination trials. The results showed that, on average, cattle visited M. sieversii trees 477.33 times during a two-month observation period. Out of these visits, 315 were specifically for fruit removal. The fruit removal rate per cattle visit was as high as 96.67%. Additionally, cattle were able to disperse M. sieversii seeds up to a maximum distance of 533.67 m, with an average dispersal distance of 134.62 m. The average distance of cattle movement was recorded as 176.95 m/h, with peak activity observed during 11:00–13:00 and 19:00–21:00. The germination rate of M. sieversii seeds that passed through the digestive tract of cattle was significantly higher than that of control seeds. Finally, the emergence rate and survival rate of seeds dispersed by cattle to forest edges and gaps were significantly higher than those dispersed to understory. These findings suggest that cattle can serve as effective long-distance dispersers of M. sieversii seeds and may play a crucial role in the regeneration and expansion of M. sieversii populations in the Ili Botanical Garden.

Calcium regulation of the Arabidopsis Na+/K+ transporter HKT1;1 improves seed germination under salt stress.

Calcium is known to improve seed-germination rates under salt stress. We investigated the involvement of calcium ions (Ca2+) in regulating HIGH-AFFINITY K+ TRANSPORTER 1 (HKT1; 1), which encodes a Na+/K+ transporter, and its post-translational regulator TYPE 2C PROTEIN PHOSPHATASE 49 (PP2C49), in germinating Arabidopsis (Arabidopsis thaliana) seedlings. Germination rates of hkt1 mutant seeds under salt stress remained unchanged by CaCl2 treatment in wild-type Arabidopsis, whereas pp2c49 mutant seeds displayed improved salt-stress tolerance in the absence of CaCl2 supplementation. Analysis of HKT1;1 and PP2C49 promoter activity revealed that CaCl2 treatment results in radicle-focused expression of HKT1;1 and reduction of the native radicle-exclusive expression of PP2C49. Ion-content analysis indicated that CaCl2 treatment improves K+ retention in germinating wild-type seedlings under salt stress, but not in hkt1 seedlings. Transgenic seedlings designed to exclusively express HKT1;1 in the radicle during germination displayed higher germination rates under salt stress than the wild type in the absence of CaCl2 treatment. Transcriptome analysis of germinating seedlings treated with CaCl2, NaCl, or both revealed 118 upregulated and 94 downregulated genes as responsive to the combined treatment. Bioinformatics analysis of the upstream sequences of CaCl2-NaCl-treatment-responsive upregulated genes revealed the abscisic acid response element CACGTGTC, a potential CaM-binding transcription activator-binding motif, as most prominent. Our findings suggest a key role for Ca2+ in mediating salt-stress responses during germination by regulating genes that function to maintain Na+ and K+ homeostasis, which is vital for seed germination under salt stress.

The Ideal Seeding Rate of Rice Cultivars Depending on Grain Yield

This study aimed to determine the optimum seeding rate of rice (Oryza Sativa L.) cultivars in iraq. The experiment was conducted at Al Diwaniyah Research Station, Agricultural Research Office/Ministry of Agriculture for two seasons 2019 and 2021. A Factorial Experiment Design was used According to RCBD design in an order of split plot with three replicates, The main plots occupied the cultivars factor which was: - Yasamine (Y), Forat (F), Dijla (D), Baraka (B), Gadeer (G) and Anbar (A). While the seeding rate factor filled sub plots: - 40, 60, 80, 100, 120, 140 Kg ha-1. The research results for both seasons, indicated that each cultivar had an ideal seeding rate, as the seeding rate for the Y variety is 120 kgha-1, as it gave the best leaf area, the weight of 1000 grain, and the grains panicles-1, which was reflected in the best grain yield at this level. The results also showed that the seeding rate for the F variety was 140 kgha-1, as it gave the best plant height, panicles m-2, weight of 1000 grain, and grains panicles-1, thus giving the best grain yield at this level. The results showed that the seeding rate for variety D was 140 kgha-1, which gave the best plant height, leaf area, panicles m-2, and grains panicles-1, which reflected positively on the best grain yield at this level. The results indicated that the seeding rate for variety B was kgha-1, as it gave the best plant height, panicle m-2, unfertility, and grains panicles-1, which was reflected in the best grain yield at this level. As for the G variety, the best seeding rate was 120 kgha-1, as it excelled in all the studied treatments (plant height, panicle length, leaf area, panicles m-2, weight of 1000 grain, unfertility, and grains panicles-1), which was significantly reflected on the grain yield at this level. Whereas, cultivar A showed that the best seeding rate was 140 kgha-1 if it gave the best plant height, leaf area and panicles m-2 and thus gave the best grain yield at this level.