Net Assimilation Research Articles

Effects of Nutrient Management on Growth Indices and Grain Yield of Different Crop Establishment Methods in Rice (Oryza sativa L.)

A field experiment was conducted during two consecutive Kharif seasons, 2021 and 2022 at Agronomy Research Farm, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj Ayodhya (Uttar Pradesh, India) to assess the effect of crop establishment methods and nutrient management on growth indices and yield of rice (Oryza sativa L.). The experiment was conducted in split plot design which comprised of four crop establishment methods. There are: M1 transplanting (Conventional); M2 direct seeded rice; M3 drum seeded rice and M4 broadcasting sprouted seed under puddled condition were kept in main plot while five nutrient management practices were kept in sub plot. They are: N0 Control; N1 Recommended dose of fertilizer (150:60:40 kg/ha NPK); N2: RDF + Zn@5kg/ha; N3: RDF + S@40 kg/ha; N4: RDF + Zn + S (@5 + 40 kg/ha). The experiment was replicated three times. Significantly higher crop growth rate, absolute growth rate, relative growth rate and net assimilation rate growth and grain yield was recorded in transplanting methods during both the years of investigation. Among the nutrients management; higher value of all the growth indices and grain yield was recorded in 150:60:60 kg/ha NPK + Zn (5 kg/ha) + Sulphur (40 kg/ha).

Phytohormones Promote the Growth, Pigment Biosynthesis and Productivity of Green Gram [Vigna radiata (L.) R. Wilczek

Globally, optimized doses of exogenously applied growth regulators hold the potential to sustainably boost the growth and productivity of leguminous crops, including green gram. A field investigation was undertaken at the Agronomy Farm of the University of Agriculture Faisalabad, Pakistan in 2021–2022 to determine the highest-performing doses of foliar-applied salicylic acid (S1 = 0 and S2 = 75 ppm) and gibberellic acid (G1 = 0, G2 = 30, G3 = 60, G4 = 90 and G5 = 120 ppm) for green gram (cv. NIAB-MUNG 2011) sown under irrigated conditions in a semiarid climate. The response variables included physiological growth traits (CGR and net assimilation rate (NAR)), yield attributes (plant height (PH), PBs and the number of pods per plant−1 (NP), pod length (PL) and SW, grain (GY) and biological yields (BY), the biosynthesis of pigments (chlorophyll a, chlorophyll b and total chlorophyll along with carotenoids) and protein (P) contents. The results revealed that S2G5 remained unmatched in that it exhibited the highest crop growth rate, while it remained on par with S2G4 and S2G3 in terms of its net assimilation rate. Additionally, S2G5 maximized plant height, the number of pod-bearing branches and pods per plant, pod length, seed number per pod−1 and 1000-seed weight, which led to the highest grain yield and biological yield (104% and 69% greater than those of the control, respectively). Moreover, the same treatment combination also surpassed the rest of the treatments because it recorded the largest amounts of chlorophyll and carotenoid contents, and the P content was increased to 24% greater than that observed for the control treatment. Thus, the exogenous application of salicylic acid (75 ppm) and gibberellic acid (120 ppm) might be recommended to green gram growers to sustainably increase the plant’s yield and nutritional value, and these findings may serve as a baseline for conducting more studies to test higher doses of these growth regulators.

Pantoea conspicua promoted sunflower growth and engulfed rhizospheric arsenate by secreting exopolysaccharide

A rhizobacterium, Pantoea conspicua, was examined against sunflower seedlings' growth under arsenate stress. Sunflower upon exposure to arsenate resulted in compromised growth that might be due to the accumulation of higher concentrations of arsenate and reactive oxygen species (ROS) in seedlings' tissues. The deposited arsenate led to oxidative damage and electrolyte leakage, making the sunflower seedlings vulnerable to compromise its growth and development. However, inoculation of sunflower seedlings with P. conspicua alleviated arsenate stress in host by initiating a multilayered defence mechanism. In fact, P. conspicua filtered out 75.1% of the arsenate from growth medium that were available to the plant roots in the absence of the said strain. To accomplish such activity, P. conspicua secreted exopolysaccharides as well as altered lignification in host roots. The arsenate (24.9%) that made its way to plant tissues was countered by helping the host seedlings to produce higher levels of indole acetic acid, non enzymatic antioxidants (phenolics and flavonoids) and antioxidant enzymes (catalase, ascorbte peroxidase, peroxidase, superoxide dismutase). As a result, ROS accumulation and electrolyte leakage were brought back to normal levels as observed in control seedlings. Hence, the rhizobacterium associated host seedlings achieved higher net assimilation (127.7%) and relative growth rate (113.5%) under 100 ppm of arsenate stress. The work concluded that P. conspicua alleviated arsenate stress in the host plants by imposing physical barrier as well as improving host seedlings’ physiology and biochemistry.

THE EFFECT OF SEEDING DENSITY AND POTASSIUM RATES ON GROWTH AND YIELD OF PSYLLIUM SEED (Plantago ovata)

The study was conducted on psyllium seed to assess the combine effect of seeding density and potassium rates on growth, productivity and yield. A factorial study was carried out in Randomized Complete Block Design (RCBD), during winter season of 2020-21, at Tobacco and Medicinal Crop Research Institute, Tandojam. The seeding densities were maintained at 6.5, 7.5 and 8.5 kg ha-1. Whereas potassium was applied @ 0, 20, 40, 60, 80 and 100 kg ha-1. The data were recorded for various quantitative, qualitative and yield parameters. The results shown that all quantitative parameters had non-significant effect of various potassium levels and seeding density except plants m-2. The values of plants m-2 were observed higher at potassium level 100 kg ha-1 and seeding density level of 8.5 kg ha-1. While the qualitative parameters had significant differences due to various potassium levels and seeding density, excludes days to 50% spike emergence, days to 50% maturity and seed index. The seed weight spike-1 (g), seed index (g) and seed yield (kg ha-1) were observed maximum from the plants where potash was applied at 100 kg ha-1. In qualitative parameters, the seeding density at 7.5 kg ha-1observed higher seed yield (1152.33 kg ha-1). While higher seed weight spike-1 (0.14g) observed at seeding density 6.5 kg ha-1. Among growth parameter, leaf area was increased at potash level 60 kg ha-1 and the values of seeding density showed higher leaf area at seeding density level 8.5 kg ha-1. The same pattern showed of leaf area index where seeding density was higher at seeding density 8.5 kg ha-1. Leaf area duration and total dry matter were found significantly higher at potash level 100 kg ha-1 and seeding density 8.5 kg ha-1. While the net assimilation rate was greater at seeding density level 8.5 kg ha-1. It is concluded from the results that and seeding density 7.5 kg ha-1 and increased levels of potassium at 100 kg ha-1 had ensure better results for most quantitative, qualitative and yield attributes.

Differential effect of water salinity levels on gas exchange, chlorophyll fluorescence and antioxidant compounds in ex vitro date palm plants

In this study, the response to salt stress was evaluated in ex vitro acclimated date palm plants, regenerated from in vitro culture multiplication. The plants, eighteen-month-old, were irrigated with 0 (control), 150, 300 or 450 mM NaCl solutions (high to very high-water salinity). Photosynthesis parameters and antioxidant compounds were determined at the end of the experiment in leaves. At 150 mM NaCl, net CO2 assimilation rate and internal CO2 concentration were not impaired; while transpiration and stomatal conductance decreased by 60 and 70%, respectively. By increasing salt concentrations, all gas exchanges parameters were decreased. Measurement of chlorophyll fluorescence and P700 redox state showed that PSII and PSI machineries were significantly enhanced under 150 mM NaCl, conditions. With the 300 mM NaCl, the PSI parameters remained unchanged compared to control, while some of the PSII parameters, such as NPQ and Y (NPQ), were increased. At 450 mM NaCl, photosystems functionality was light intensity (PAR) dependent. Only at low PAR, a significant increase of some PSI and PSII parameters was observed. At the contrary, with high PAR, most of the energy conversion functions were significantly reduced, especially those related to PSI, indicating that PSI was more susceptible for damage by salinity than PSII. To overcome high salinity stress, ex vitro date palm plants mobilized a cascade of physio-biochemical pathways including the antioxidant activity and proline biosynthesis. Overall, the salinity of irrigation water, and up to 150 mM, improves the physiological performance of ex vitro date palm plants, which manage to tolerate very high levels of this stress.

Comparative study of newly-bred black locust clones with regard to photosynthetic rate and water use efficiency: early evaluation

Black locust (Robinia pseudoacacia L.) is one of the most important tree species in Hungary, due to its positive economic impacts. Research to increase its yield, improve its stem quality and enhance its drought tolerance has been ongoing since the 1960s. Of the current research works in this field, the clone trial of the Forest Research Institute, University of Sopron, established in 2020 in the Nyírség region, is worth highlighting. In this experiment 4 newly-bred clones and a state-approved black locust cultivar ('Üllői') are being tested. In the summer of 2022, ‘on site’ measurements of assimilation parameters – net assimilation (An), transpiration (Tr) – were carried out using the LI-6800 portable photosynthesis system. From the data obtained, the water use efficiency (WUE) was calculated. The results of the statistical analysis (Kruskal-Wallis H test) have shown significant differences (p < 0.05) between the clones for all three parameters (An, Tr, WUE) tested. The NK2 clone has performed the highest value for all the parameters studied. However, no significant differences were found between clones NK2 and PL040 for Tr or between NK2 and control ('Üllői') for WUE. Studies of this kind contribute to the improvement of black locust growing through the production and selection of cultivars, which are relatively resistant to the negative effects (drought) of climate change.

Physiological and molecular effects of TiO2 nanoparticle application on UV-A radiation stress responses in Solanum lycopersicum L.

Nanoparticles (NPs) of titanium dioxide (TiO2) alter photosynthetic and biochemical parameters in Solanum lycopersicum L., possibly due to their photocatalytic properties given by energy absorption in the UV-A range; however, the joint effects TiO2 NPs and UV-A radiation are not well understood. This work evaluates the combined responses of TiO2 NPs and UV-A radiation at the physiological and molecular levels in S. lycopersicum. In a split growth chamber, the presence (UV-A +) and absence (UV-A -) of UV-A were combined with 0 (water as a control), and 1000 and 2000mg L-1 of TiO2 NPs applied at sowing. At the end of exposure (day 30 after sowing), the photosynthetic performance was determined, and biochemical and molecular parameters were evaluated in leaf tissues. Better photochemical performance in UV-A + than UV-A - in control plants was observed, but these effects decreased in 1000 and 2000mg TiO2 L-1, similar to net CO2 assimilation. A clear increase in photosynthetic pigment levels was recorded under UV-A + compared to UV-A - that was positively correlated with photosynthetic parameters. A concomitant increase in total phenols was observed on adding TiO2 in UV-A - conditions, while a decreasing trend in lipid peroxidation was observed for the same treatments. There was an increase in psbB gene expression under TiO2/UV-A + treatments, and a reduced expression of rbcS and rbcL under UV-A - . These results suggest that the reduction in photosynthetic performance on applying high doses of TiO2 NPs is probably due to biochemical limitation, while UV-A achieves the same result via the photochemical component.

Developmental dynamics of crassulacean acid metabolism (CAM) in Opuntia ficus-indica.

The relative contributions of C3 photosynthesis and crassulacean acid metabolism (CAM) during the earliest stages of development were investigated to assess how much each might contribute to cactus pear (Opuntia ficus-indica) productivity. The developmental progression of C3 photosynthesis and CAM was assessed in seedlings and daughter cladodes of mature plants by titratable acidity, δ13C isotopic values and diel gas exchange measurements. Nocturnal acidification was observed in seedling cladodes and cotyledons at the earliest stages of development and became highly significant by 75 days of development. Seedling cotyledons showed mean δ13C values of -21.4 and -17.1 ‰ at 30 and 100 days of age, respectively. Seedling cladodes showed mean δ13C values of -19.4 and -14.5 ‰ at 30 and 100 days of age, respectively. These values are typical of CAM plants. Net CO2 assimilation was negative, then occurred in both the day and the night, with nighttime fixation becoming predominant once the primary cladode reached 5 cm in size. Emergent daughter cladodes growing on mature plants showed nocturnal titratable acidity at the earliest stages of development, which became significant when daughter cladodes were >2.5-5 cm in height. Emergent daughter cladodes showed mean δ13C values of -14.5 to -15.6 ‰, typical of CAM plants. CO2 assimilation studies revealed that net CO2 uptake was negative in daughter cladodes <12 cm in length, but then exhibited net positive CO2 assimilation in both the day and the night, with net nocturnal CO2 assimilation predominating once the daughter cladode grew larger. Developing O. ficus-indica primary and daughter cladodes begin as respiring sink tissues that transition directly to performing CAM once net positive CO2 fixation is observed. Overall, these results demonstrate that CAM is the primary form of photosynthetic carbon assimilation for O. ficus-indica even at the earliest stages of seedling or daughter cladode development.

Mesh Crop Cover Optimizes the Microenvironment in a Tropical Region and Modifies the Physiology and Metabolome in Tomato

In tropical regions, high light levels can lead to increased photooxidative damage in plants. Thus, reducing solar radiation could have a substantial impact on crop performance. This study aimed to evaluate the physiological responses and metabolic profile of two tomato varieties grown in microenvironments modified with cover meshes under a high light level and a warm climate. The experiment was achieved under high solar irradiance and an unfavorably high temperature. The varieties “Moneymaker” (MM) and “Campeche 40” (C40) were grown from 45 to 130 days after sowing at four solar irradiance levels: 100% (T1), 80% (T2), 75% (T3), and 50% (T4). In both varieties, the plants grown under the lowest irradiances (T3 and T4) were the tallest, with larger leaf areas, and accumulated more aerial and root biomass. Under moderate shading (T2), plants took better advantage of the light and had the highest photochemical quenching coefficient (qP) (C40 = 0.60 and MM = 0.48) and the highest electron transport rate (ETR). However, T3 and T4 plants had the highest net assimilation rate (23.6 and 23.9 µmol m−2 s−1 in C40, and 22.7 and 22.6 µmol m−2 s−1 in MM, respectively) and the highest A/Ci coefficients. Although both tomato varieties accumulate similar metabolites, MM leaves accumulate more glucose and C40 leaves accumulate more proline and valine. Furthermore, MM leaves accumulate more glycine and GABA under high radiation, and C40 leaves accumulate more proline and valine than leaves under 50% shade (T4). We conclude that using meshes in areas with high irradiance could be an alternative to reduce abiotic stress factors in plants.

Proline as an osmolyte modulates changes in morphological and physiological attributes of Capsicum annuum l. under water stress

Abstract Water stress is an inevitable factor which limits growth, development, and production efficiency of vegetables such as Capsicum annuum (Linnaeus) (pepper). This study was carried out to investigate the use of proline as an osmolyte to ameliorate the effect of water stress on morphological and physiological attributes of Capsicum annuum. C. annuum seedlings were subjected to different levels of proline (20, 30 and 40 %) against droughted and well-watered seedlings as control in a completely randomized design. Results showed that water stress limits morphological and physiological attributes of C. annuum, while proline at different levels enhances it. Highest plant height (26.00±0.71 cm) was obtained in C. annuum sprayed with 40% proline. Well-watered seedlings of C. annuum produced the highest numbers of leaves (35.40±4.12 cm) and leaf length (12.60±0.68 cm). In addition, leaf area (89.40±2.04 cm2), specific leaf area (124.24±1.24 m2kg-1) and leaf area index (1.76±1.13 m2m-2) were significantly higher (p &lt; 0.05) in C. annuum seedlings sprayed with 40 % proline compared with other treatments. Relative growth rate (0.30±0.09 mgg-1day-1), net assimilation rate (0.47±0.30 gm-2day-1) and leaf area ratio (0.58±0.11 m2kg-1) as well as, chlorophyll content (9.76±0.02 µgcm2), were higher in C. annuum seedlings sprayed with 40% proline. In conclusion, 20 and 30 % proline sustained morphological and physiological attributes of C. annuum under water stress, but 40% proline produced better ameliorative effects.

Genotype by environment analysis on multi-canopy cropping system towards harvest in soybean

The multi-canopy cropping system is a new way to increase the number of soybeans grown. It is based on the idea of vertical agriculture. Short and tall plants are grown on the same hill in this method. The tall plants form a canopy, so the vertical space can be used to grow crops. The study aimed to determine how breeding programs could be used to create rice varieties for a multi-canopy cropping system. The tests were done in the dry and wet seasons at the Universitas Sumatera Utara in Medan, Indonesia. For plant height, number of leaves, number of branches, and number of pods, the genotype x canopy system interaction effect was significant. Over the two seasons, the average yield of the multi-canopy cropping system was 6.61 t ha−1 compared to 5.59 t ha−1 for the monoculture. The average yield of seven genotypes in two cropping systems, monoculture and multi-canopy, was 5.59 t ha−1 and 6.62 t ha−1. The mean average agronomic traits over monoculture and multi-canopy plant height, number of leaves, number of branches, and number of pods were 67.63 cm, 28.83, 8.00, and the number of pods 154.42. The AMMI analysis shows most of the differences between genotype x environment. The first group is made up of the environment during the dry season and the wet season. The mean net assimilation rate of soybean genotypes under multi-canopy and monoculture systems monoculture and multi-canopy was 1.81 μg cm2 d−1 and 2.87 μg cm2 d−1. The tall and short genotypes in multi-canopy have the highest yield, so they could be used to breed rice varieties that do well in multi-canopy.

Solar radiation utilization of five upland–paddy cropping systems in low-light regions promoted by diffuse radiation of paddy season

Solar radiation affects crop productivity in farmland ecosystems. Global dimming has resulted in decreased incident global radiation over recent decades, with a huge subsequent effect on food security. Attempting to increasing utilization of radiation and production to increase output, especially in multiple cropping systems, is a significant problem in low-light regions. Here, five upland–paddy cropping systems were evaluated in a low-light region during 2016–2017 and 2017–2018: Garlic–rice (GR), wheat–rice (WR), broad bean–rice (BR), rapeseed–rice (RR), and potato–rice (PR). Solar radiation and crop-related indicators were investigated to determine radiation utilization. The results showed that annual global radiation was 4056.97. MJ·m−2 and 3985.43 MJ·m−2 in 2016–2017 and 2017–2018, respectively, 13.69%–26.25% of which was wasted during the fallow season. Furthermore, the seasonal distribution of global radiation was differed to study years. The ratio_dif in paddy season was greater than 75%, whereas in upland season was less than 55%. Additionally, the annual radiation utilization efficiency (RUE) values of the crops investigated in this study were 0.53%–0.80% and RUE during upland season were 0.30%–0.95%, compared to 0.99%–1.35% during paddy season. The ratio_dif during paddy season had a greater contribution to RUE than that of the upland season, whilst the ratio_dif had a positive relationship with RUE. Therefore, in the low light region the high radiation utilization of upland-paddy systems could primarily be attributed to the efficient utilization of diffuse radiation by rice, which had a high radiation interception, net photosynthesis and net assimilation rate. This increase in diffuse radiation will further promote the efficient use of radiation in low-light regions. Furthermore, planting the upland crops with long growth period (garlic) and high planting intensity (wheat and rapeseed) could take advantage of limited global radiation in low-light regions. Our study clarifies RUE magnitude and its causes in upland–paddy cropping systems in low-light regions, while also providing a theoretical reference for grain production prediction and crop RUE improvement within the context of global dimming.

Photosynthesis, Biochemical and Yield Performance of Grapevine Hybrids in Two Rootstock and Trellis Height

The interaction between variety, rootstock, and trellis height is important for grapevine management, mainly for producing new varieties of grapes for juice and wine in new wine-growing regions with high production potential. Then, this study aimed to evaluate the rootstocks and trellis height influence on photosynthesis, biochemical, and yield performance for grapevine hybrids. The experiment was carried out in a randomized block design using two factors, rootstocks (‘IAC 766’ and ‘106-8 Mgt’) and trellis height (until 1.6 and 2.0 m), evaluated for two grapevine hybrids (IAC 138-22 ‘Maximo’ and ‘BRS Violeta’). During grapevine flowering, it was evaluated photosynthesis and biochemical performance, for this, the gaseous exchanges were measured using the open system photosynthesis equipment with a CO2 analyzer and water vapor by infrared radiation, being net assimilation rate of CO2, stomatal conductance, transpiration rate, internal CO2 concentration, water use efficiency, carboxylation efficiency (Rubisco), and the flux density of photosynthetically active photons. At the stages of grapevine flowering and ripening berries were evaluated the antioxidant enzymes (peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT)), total soluble proteins, chlorophylls, and SPAD. The interaction between rootstock and trellis heigh influenced varieties’ photosynthesis, biochemical, and yield performance. In conclusion under subtropical conditions, better photosynthesis, biochemical, and yield performance were observed when both cultivars were grafted on the ‘IAC 766’ rootstock. The ‘IAC 138-22 Maximo’ was trained until 2.0 and grafted on the ‘IAC 766’ rootstock, increasing grape production and photosynthesis efficiency. In addition, this variety was more productive than ‘BRS Violeta’.

Rubisco deactivation and chloroplast electron transport rates co-limit photosynthesis above optimal leaf temperature in terrestrial plants

Net photosynthetic CO2 assimilation rate (An) decreases at leaf temperatures above a relatively mild optimum (Topt) in most higher plants. This decline is often attributed to reduced CO2 conductance, increased CO2 loss from photorespiration and respiration, reduced chloroplast electron transport rate (J), or deactivation of Ribulose-1,5-bisphosphate Carboxylase Oxygenase (Rubisco). However, it is unclear which of these factors can best predict species independent declines in An at high temperature. We show that independent of species, and on a global scale, the observed decline in An with rising temperatures can be effectively accounted for by Rubisco deactivation and declines in J. Our finding that An declines with Rubisco deactivation and J supports a coordinated down-regulation of Rubisco and chloroplast electron transport rates to heat stress. We provide a model that, in the absence of CO2 supply limitations, can predict the response of photosynthesis to short-term increases in leaf temperature.

GROWTH ANALYSIS OF EPIPREMNUM AUREUM (L.) ENGL. IN RESPONSE TO SALINITY STRESS

Potted plants of Epipremnum aureum (L.) Engl. were submitted to salinity stress (0, 100 ppm and 500 ppm NaCl irrigation) for 28 days in order to assess the effect on growth parameters viz. Relative Growth Rate (RGR), Net Assimilation Rate (NAR) and Leaf Weight Ratio (LWR). The salt stress caused reduction in LWR, NAR and RGR. It was observed that the effect of salinity was more pronounced on growth parameters at higher concentration than that at lower concentration.

The Effect of Organic Manure and Days of Incorporation on the Growth and Yield of Lettuce (Lactuca sativa L.) Grown in Jos Plateau State. Nigeria

The experiment aimed to evaluate effect of organic manure on the growth and yield of lettuce (Lactuca sativa L.) grown in Jos Plateau State, Nigeria. The treatments used are organic manure source (Poultry dropping, Cow dung, goat manure, dung site and control) and time of inclusion (5, 10 and 15 days before transplanting) was adopted for the experiment. The experiment is laid in a randomized complete block design with three replications, with 12 plots in a block and 45 plots for the whole experiment. Data were collected from the following parameters, plant height, plant diameter, number of leaves, leaf area (LA), net assimilation rate (NAR), crop growth rate (CGR), fresh weight, and dry weight. All the study parameters of lettuce were significantly different (P&lt;0.05) on both organic manure, days of inclusion and season. Poultry droppings produce plant height (25.73), plant diameter (8.42), number of leaves (32.02), leaf area index (16.75), net assimilation rate (4.67), crop growth rate (3.20), fresh weight (6.65 ha-1), and dry weight (4.23 ha-1) when compared with other sources of nutrient. Similarly maximum plant height (23.32), plant diameter (6.66), number of leaves (31.86), leaf area (15.19), net assimilation rate (3.32), crop growth rate (3.54), fresh weight (5.79 ha-1), and dry weight (4.00 ha-1) was recorded in lettuce plant treated with organic manure of 5 days of inclusion. On seasons, higher plant height (25.83), plant diameter (8.23), number of leaves (31.34), leaf area (15.32), net assimilation rate (4.00), crop growth rate (3.61), fresh weight (7.01 ha-1), and dry weight (5.99 ha-1) &nbsp;was obtained in 2021 as against 2020 season. Based on the results obtained, it can be recommended to lettuce farmers in the locality the use of poultry manure and 5 days of inclusion for optimum growth and yield of lettuce.

Drought-triggered leaf transcriptional responses disclose key molecular pathways underlying leaf water use efficiency in sugarcane (Saccharum spp.).

Drought is a major constraint to sugarcane (Saccharum spp.) production and improving the water use efficiency (WUE) is a critical trait for the sustainability of this bioenergy crop. The molecular mechanism underlying WUE remains underexplored in sugarcane. Here, we investigated the drought-triggered physiological and transcriptional responses of two sugarcane cultivars contrasting for drought tolerance, 'IACSP97-7065' (sensitive) and 'IACSP94-2094' (tolerant). After 21 days without irrigation (DWI), only 'IACSP94-2094' exhibited superior WUE and instantaneous carboxylation efficiency, with the net CO2 assimilation being less impacted when compared with 'IACSP97-7065'. RNA-seq of sugarcane leaves at 21 DWI revealed a total of 1,585 differentially expressed genes (DEGs) for both genotypes, among which 'IACSP94-2094' showed 617 (38.9%) exclusive transcripts (212 up- and 405 down-regulated). Functional enrichment analyses of these unique DEGs revealed several relevant biological processes, such as photosynthesis, transcription factors, signal transduction, solute transport, and redox homeostasis. The better drought-responsiveness of 'IACSP94-2094' suggested signaling cascades that foster transcriptional regulation of genes implicated in the Calvin cycle and transport of water and carbon dioxide, which are expected to support the high WUE and carboxylation efficiency observed for this genotype under water deficit. Moreover, the robust antioxidant system of the drought-tolerant genotype might serve as a molecular shield against the drought-associated overproduction of reactive oxygen species. This study provides relevant data that may be used to develop novel strategies for sugarcane breeding programs and to understand the genetic basis of drought tolerance and WUE improvement of sugarcane.

Combined application of organic fertilizer and chemical fertilizer alleviates the kernel position effect in summer maize by promoting post-silking nitrogen uptake and dry matter accumulation

Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields. In order to clarify whether the combined application of organic fertilizer and chemical fertilizer (CAOFCF) can alleviate the kernel position effect of summer maize, field experiments were conducted during the 2019 and 2020 growing seasons, and five treatments were assessed: CF, 100% chemical fertilizer; OFCF1, 15% organic fertilizer+85% chemical fertilizer; OFCF2, 30% organic fertilizer+70% chemical fertilizer; OFCF3, 45% organic fertilizer+55% chemical fertilizer; and OFCF4, 60% organic fertilizer+40% chemical fertilizer. Compared with the CF treatment, the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels. These effects were largely due to the improved filling and starch accumulation of inferior kernels. However, there were no obvious differences in the kernel position effect among plants treated with CF, OFCF3, or OFCF4 in most cases. Leaf area indexes, post-silking photosynthetic rates, and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF, reflecting an enhanced photosynthetic capacity and improved post-silking dry matter accumulation (DMA) in the plants treated with OFCF1 or OFCF2. Compared with the CF treatment, the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%, respectively, which was the major factor driving post-silking photosynthetic capacity and DMA. Moreover, the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence, which is associated with an increased post-silking N uptake. Analyses showed that post-silking N uptake, DMA, and grain yield in summer maize were negatively correlated with the kernel position effect. In conclusion, the combined application of 15–30% organic fertilizer and 70–85% chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA. These results provide new insights into how CAOFCF can be used to improve maize productivity.

Effect Of Nitrogen Fertilizer on The Growth of Hybrid Sorghum Sudan Grass

A pot experiment was conducted at Experimental area, Agronomy Department PMAS- University of Arid Agriculture Rawalpindi to see the effect of different levels of nitrogen fertilizer on the growth and physiological traits of Sorghum Sudan Grass during March, 2022. Completely randomized designed was applied along with three replications. Seeds of Sorghum Sudan grass were collected from NARC Islamabad. Nitrogen fertilizer was applied in pots on 30th March, 2022, according to the treatments. Nitrogen played a significant role in the growth and physiology of Sorghum Sudan Grass. Nitrogen @ 150 kgha-1 is the best among other four treatments and attained the highest plant heights in three times (21.355, 65. 153 and 100.620 cm) respectively. However, results of nitrogen @ 200kgha-1 are approximately statistically at par with NPK. Nitrogen @ 150 kgha-1 gained the highest position in two times data (0.7050 and 1.4250) respectively. Nitrogen @ 200 kgha-1 gained less value than nitrogen @150kgha-1 might be excessive dose. Nitrogen nutrition played a key role in the enhancement of leaf area values; however nitrogen @150kgha-1nutrition had the top position (1.140 and 1.950) during two times respectively. Leaf area index data had statistically significant results but among the nutrition treatments nitrogen @150kgha-1nutrition is the best option attaining the highest values (91.475 and 152.550) respectively in two times. Nitrogen fertilizer at different levels had statistically significant effect on crop growth rate of sorghum plants; however nitrogen @150kgha-1nutrition treatment attained the highest value (0.5333) which was statically at par @200kgha-1nutrition treatment. Nitrogen @150kgha-1nutrition treatment had the top position (4061.9) but other three doses of nitrogen values having minute difference with nitrogen @150kgha-1 and higher than control. Four doses of nitrogen fertilizer produced more net assimilation rates than control and nitrogen @150kgha-1gained the highest value (45.653) which was statistically at par with nitrogen @200kgha-1(43.521).Nitrogen fertilizer is an inorganic fertilizer provides the nutrition the plant fastly and provides better performance at nitrogen @150kgha-1. Nitrogen @200kgha-1 showed better performance than control but less than nitrogen @150kgha-1, therefore this finding improves the economics of the study.

Pemanfaatan Sistem Tanam Tumpangsari terhadap Pertumbuhan Vegetatif Dua Kultivar Tanaman Kedelai Hitam (Gylcine Max L)

This study aims to determine the use of spacing and cultivars for the growth of black soybean plants with an intercropping system (Gylcine max L.). This research method used a factorial randomized block design (RBD) with 2 factorials and 4 replications. Factor I (K) cultivars were K1 = detam 2 soybean cultivar and K2 = detam 4 soybean cultivar. The interval (J) consisted of three levels: J1 = 10 x 20 cm, J2 = 15 x 20 cm, J3 = 20 x 20 cm . The observed variables were plant height, leaf area index, root nodules, relative growth rate (LPR), chlorophyll content, and net assimilation rate (LAB). The results showed that treatment with K2 (detam 4) had a significant effect on plant height 14.28 HST, relative growth rate, chlorophyll a, b and total. The treatment of J1 spacing (10 x 20 cm) had a significant effect on 14 DAP height and leaf area index. Based on the research, it can be concluded that the intercropping system and black soybean cultivar had a significant effect on plant height, relative growth rate, chlorophyll a, b, total, and leaf area index.&#x0D; Keywords: Spacing, Black Soybean, Cultivars, Growth, Intercropping