Sodic Conditions Research Articles

Identification of sodicity-tolerant banana varieties to harness the salt-affected ecosystem

"Salt Affected Soils" (SAS) refers to a category of soils that contain either an excess of soluble salts or exchangeable sodium. Soils are divided into four categories: normal, saline, sodic, and saline-sodic, based on the electrical conductivity (EC), pH and exchangeable sodium percentage (ESP) measurements. At the Horticultural College and Research Institute for Women in Trichy, fifteen genotypes of bananas were assessed for growth, yield, and physiological parameters in a saline-sodic environment. Four replications of the field experiment were set up in RBD and evaluated for three years. The growth physiological and biochemical characters were recorded in the seventh month after planting (MAP), and the bunch characters were recorded at harvest time. FHIA 1 (83.4%), Saba (81.0%) and Karpooravalli (78.0%) had the highest relative water content. The highest yield was recorded in FHIA-1 (23.5 kg), Saba (22.2 kg), Udhayam (22.5 kg) and Karpooravalli (22.0 kg). The sodicity injury symptoms in the leaves were evaluated using a scoring technique, and the genotypes FHIA-1(1.0) Saba recorded the lowest score for sodicity damage. A significant negative correlation was observed between salt injury degree and leaf K+/Na+. So, the varieties that maintain higher K+/Na+ ratio in leaf and root are salt tolerant. The general ranking of the banana varieties for salt tolerance was FHIA 1 > Saba > Karpooravalli > Bangrier > Ash Monthan > Veneetu Mannan > Udhayam. A comparative field trial for the 15 banana types showed that Saba, FHIA-1 and Karpooravalli could withstand sodic conditions in the field in terms of bunch characteristics, biochemical parameters, and plant growth. Grand Naine, Rasthali and CO 1 were vulnerable to sodicity stress. Regardless of cultivar, sodicity stress increased the days needed for shooting and harvest.

Design and Evaluation of Elevated Field Beds of Fish Pond based Integrated Farming Model under Waterlogged Sodic Conditions in Canal Command

Design and Evaluation of Elevated Field Beds of Fish Pond based Integrated Farming Model under Waterlogged Sodic Conditions in Canal Command

Genotypic Variability in Wheat Response to Sodicity: Evaluating Growth and Ion Accumulation in the Root and Shoot

Soil sodicity is a major constraint to seedling emergence and crop production, potentially reducing plant growth due to physical and chemical constraints. Studying responses to ion imbalances may help identify genotypes tolerant to chemical constraints in sodic soils, thereby improving productivity. We evaluated the performance of four wheat (Triticum aestivum L.) genotypes in solutions with five sodium adsorption ratios (SARs) ranging from 0 to 60. For all four genotypes, seedling emergence and shoot dry matter (DM) decreased significantly with increasing SARs. A significant positive correlation was observed between Ca concentration in roots as well as both root and shoot DM for all genotypes. At SAR values > 20, the more tolerant genotype (EGA Gregory) displayed higher Ca concentrations in root tissues, whereas the more sensitive genotype (Baxter) exhibited Na-induced Ca deficiency. Thus, the selection of genotypes that are able to accumulate Ca in roots in sodic conditions may be a useful trait for selecting genotypes tolerant of soils with high ESP values. However, for soils that restrict plant growth at ESP (SAR) values of 6–10%, it is likely that growth is restricted by physical constraints rather than by a Na-induced Ca deficiency.

Modulating Effect of PGRs on Growth and Biochemical Traits in Rice (Oryza sativa L.) under Salt Stress

An investigation was conducted to study the effect of plant growth regulators on rice (variety Sarju-52) grown under sodic conditions, during the kharifseason 2018 at the students’ instructional farm of ANDUA&T, Kumarganj, Ayodhya. The experiment was laid out in randomized block design with nine treatments and three replications, with different concentrations and modes of application of plant growth regulators (PGRs). The PGRs were applied as follows- seed priming of GA3 @25 ppm & 50 ppm and SA @ 10 ppm & 25 ppm, and foliar application of GA3 and SA, each @ 100 ppm & 200 ppm at 30 (DAT), along with untreated control. Seed priming was done for 12 hours in different concentrations of PGRs. Thirty five days old seedlings were transplanted to the field from the nursery. Observations were recorded on various growth parameters such as plant height, number of tillers, dry biomass/hill, relative water content and biochemical parameters like chlorophyll, and TSS, at 30, 60 and 90 DAT and at maturity (harvesting stage). Both seed priming and foliar application of PGRs positively influenced the growth characters, chlorophyll content, and total soluble sugars. Moreover, foliar spray of GA3 @200 ppm was found to have a more pronounced effect in improving the yield of the variety studied, among all the treatments, under sodic conditions. It can be concluded that foliar spray of GA3 @ 200 ppm is effective in improving the growth and yield of rice grown under salt stress.

Response of Rice (Oryza sativa L.) Varieties to Salicylic Acid, Potassium Silicate and Tamarind Extract in Saline Soils of Kano River Irrigation Scheme Nigeria

The experiment was carried out in the Eastern and Western sectors of Kano River Irrigation Scheme, Kano State latitude 11º 45’N and 12º 05’ N and longitude 8º 45’ E and 9º 05’ E in the Sudan Savanna Agro-ecology of Nigeria, during the dry season of 2020 and 2021. The experiment was therefore conceived with the aim of introducing improved salt tolerant varieties to farmers in addition to enhancing their tolerance using synthetic and natural plant growth regulators. The treatments consisted of four rice varieties made up of 2 salt tolerant accessions {Arica 1 and Arica 2, 1 blast resistant variety (Gawal R1) and a variety (FARO 44) as a check} these were factorially combined with foliar application of salicylic acid (0.2g in 1L of water), potassium silicate (16 g/L-1 of K2SiO3), tamarind extract 8% (320ml of extract in 1 liter of water) and a zero control (0). The treatments were laid out in a Randomized Complete Block Design (RCBD) which consisted of 16 treatments replicated six times with a farmer constituting a replication. Results have shown that plant height, leaf area index (LAI), photosynthetically active radiation (PAR), chlorophyll content and the yield were all significantly affected by varietal differences except total number of tillers per plant in 2020. However, in 2021 LAI, PAR and chlorophyll content were not significantly affected by differences due to varieties but the remaining characters differed significantly. Exogenous factors had no effect on all the characters in 2020 but significantly influenced the chlorophyll content, total number of tillers and the yield in 2021. Arica 1 and Faro 44 gave the highest yield. Among the exogenous factors Tamarind extract had significantly heavier paddy yield than the control but was similar to other exogenous factors in terms of effectiveness. Tamarind extract could therefore be suggested to farmers when growing rice under saline or sodic condition in the irrigation scheme due to its lower cost and availability.

Evaluation of Genetic Diversity in Sodic Soil-grown Barnyard Millet (Echinochloa frumentacea (Roxb.) Link) Germplasm

Aims: Barnyard millet (Echinochloa frumentacea) is a significant tiny millet crop characterized by because of its high nutritional value, exceptional ability to withstand extremes of climate, and short duration. Globally, the area under salt affected soil is expanding. Therefore, genetic diversity analysis was conducted to identify genetically diverse genotypes for yield improvement under sodic condition.
 Study Design: Randomised block design.
 Place and Duration of Study: An experiment was carried under sodic soil condition at Anbil Dharmalingam Agricultural College and Research Institute, Trichy, Tamil Nadu.
 Methodology: Ninety two genotypes of barnyard millet, including two commercial check varieties, MDU1 and CO (KV) 2. Plant height (cm), inflorescence length (cm), inflorescence width (cm), lower raceme length (cm), flag leaf length (cm), flag leaf width (cm), number of leaves on main tiller, number of productive tillers per plant, and grain yield per plant (g) were the nine quantitative traits that were recorded. GENRES software version 3.11 was used for analysing the data.
 Results: For all of the analysed attributes, the genotypes showed significant differences based on the analysis of variance. Ninety two genotypes were divided into nine groups according to nine quantitative features using Mahalanobis D2-Statistics. Cluster II was the one with the greatest number with 25 genotypes, followed by cluster V with 22 genotypes, Cluster VI with 17 genotypes, Cluster IV with 11 genotypes, Cluster I with 8 genotypes, Cluster VIII with 4 genotypes, Cluster III and VII with only 2 genotypes per cluster, and Cluster IX with just 1 genotype. Cluster IV was second in terms of intra-cluster distance, after Cluster VIII. The largest inter-cluster distance was observed between clusters I (TNAUF01000021 - EF 37, TNAUF01000022 - EF 38, TNAUF01000022 - EF 39, etc.) and IX (MDU1).
 Conclusion: Choosing these genotypes as parents from genetically diverse clusters for breeding programmes might produce heterotic hybrids that produce enough genetic diversity in barnyard millet genotypes under sodic soil conditions.

Understanding physiological and molecular adaptations of three diverse halophytic grasses under saline and sodic stresses

Physiological and biochemical analyses of three halophytes were conducted to explore their tolerance and phytoremediation potential. The halophytes Urochondra setulosa, Sporobolus marginatus and Leptochloa fusca were categorised based on gas exchange attributes, antioxidant system, biomass production under soil salinity (ECe 30-50 dS/m) and sodicity (pH 9.5-10). L. fusca and S. marginatus produced slightly higher biomass under the sodic condition of pH 9.5, while in U. setulosa, it increased under salinity stress. Under sodic conditions, L. fusca showed less reduction in potassium content and maintained a higher K+/Na+ ratio in their leaf tissues. A maximum decrease in net photosynthesis was observed in L. fusca (28.55%) at ECe ~ 50 dS m-1 while minimum in S. marginatus (13.73%) at pH ~ 10.0. Comparatively, U. setulosa showed higher stomatal conductance and transpiration rate than L. fusca and S. marginatus. At the highest pH and salinity, the antioxidant activities of enzymes APX, SOD, GR and POX increased in all three halophytes. Quantitative expression of MnSOD, NHX1 and FuSOS1 genes in all three halophytes increased with salt stresses. Based on these indicators, these halophytes were categorised as salt-tolerant or alkaline-stress-tolerant.

Sodium substitutes potassium requirements of sugar beet under saline–sodic conditions

AbstractBackgroundPotassium (K) substitution by sodium (Na) in sugar beet nutrition has been investigated during the last two decades and promising results have been revealed. However, substitution is still not used in agriculture although it has been recommended that Na can replace K to a large degree, proposing an interesting fertilization strategy for such plants. This study investigates the feasibility of sugar beet production on saline–sodic soils considering Na as a substituent for K.AimsThe aim of this study is to develop a fertilizer strategy considering Na concentration in saline–sodic soils as a partial substituent to K fertilizer and to determine the level of substitution.MethodsTwo saline–sodic soils (SAR15 and SAR19 representing sodium adsorption ratios 15 and 19 [mmol L–1]1/2, respectively) with low plant‐available K were selected to investigate the substitution of K fertilizer requirements with indigenous soil Na. A pot experiment was conducted with 20 kg soil per pot having four treatments, that is, KA: recommended K; KB: recommended K–K equivalent to 2.5% of soil Na; KC: recommended K–K equivalent to 5% of soil Na; and control without K fertilizer application were established mixing potassium sulfate (K2SO4) in the soil at the time of sugar beet sowing. The sugar beet plants were harvested 90 days after sowing.ResultsThe results revealed that total plant biomass was significantly improved in KB as compared to KA. This indicates that K requirement of sugar beet was substituted by Na, and KB provided optimum results on SAR15 as compared SAR19 considering all other K combinations.ConclusionIn sugar beet nutrition, K can be replaced by Na to a large degree on saline–sodic soils under K‐deficient conditions. Therefore, sugar beet production on marginal saline–sodic soil can be a win–win strategy boosting sugar beet production and reducing input cost.

A dynamic model for salinity and sodicity management on agricultural lands: Interactive simulation approach

In this research, a dynamic simulation model, SAMIMI (Salinity/Sodicity Management with an Interactive Model Interface), is developed for managing the effects of agricultural water use and crop choices on soil salinization and sodification, and their impacts on crop yields. SAMIMI integrates the vertical hydraulic flow, solute transport, and crop processes in feedback by a compartmental, non-linear model architecture. With its holistic integrated approach to salinity /sodicity processes, it adopts a system dynamics approach. Though it is simplified in spatial resolution, the model credibility is sufficiently evaluated with indirect structure tests and against the data by Hydrus-1D, and soil-column experiments that were conducted as part of the SAMIMI (Salinity/Sodicity Management Interdisciplinary Multi-Institutional Network) project conducted in the semi-arid Konya Closed Basin of Turkey. Model analysis provide valuable insights to the role of irrigation efficiency, water quality and crop choices on soil degradation and yield losses, which are important for learning about and management of salinity/sodicity related problems: Although irrigation efficiency is desirable for water conservation purposes, it may result in higher salinity /sodicity levels because of insufficient leaching in well drained soil profiles. Salinity and sodicity have opposite effects on soil hydraulic conductivity, and while low saline irrigation water is desirable for agricultural production, under relatively high sodic conditions, it can lead to reduced hydraulic conductivity which can degrade soil characteristics to the detriment of crops. Salinity is not simply correlated with relative irrigation water consumption but with the crop salt tolerance as well. Hence, low water consuming crops with high salt tolerance can lead to over salinization, rendering the soil profiles inappropriate for cultivation of salt vulnerable crops, if not sufficiently leached before by precipitation and/or good-quality irrigation water. The model is published as a publicly available online interactive simulation tool with a fast-simulating user-friendly interface targeting researchers, students, experts, farmers and policy makers.

Screening of Rice Genotypes against Sodicity in Relation to Physiological and Biological Traits

The study aimed to screen the rice genotypes against sodicity in relation to physiological and biological traits to identify the tolerant and susceptible genotypes. The field experiment was carried out at the Research Farm of Dr. Rajendra prasad central agricultural university, Pusa, Samastipur, Bihar during Kharif season of 2019-2020. The experiment was based on randomized block design with 30 plots in each of 3 replications where each replication consists of 30 rice genotypes. A total of 30 rice genotypes were screened of which 25 are exotic and 5 are indigenous. The exotic genotypes are GPV 1, GPV 2, GPV 3, RMS 1, RMS 2, RMS 3, RMS 4, RMS 5, RMS 6, RMS 7, RMS 8, SRL 1, SRL 2, SRL 3, CNN 1, CNN 2, KRH 4, PVP 221, MTU 1010, VR 181, PS 344, MTP 1, Vardhan, Rasi, CSR 23 (Check) while Prabhat, R. Sweta, R. Bhagwati, R. Mahsuri and Rajshree are the indigenous ones. The physiological and biological traits were evaluated at tillering and pre-flowering stages and their inter-relationship among various physiological parameters are established. The genotypes such as SRL 1, GPV 1, GPV 2, GPV 3, and Rajendra Mahsuri show the highest chlorophyll content, SPAD value, peroxidase and catalase activity, proline content, RLWC content, and MSI percentage, and the lowest was found in Prabhat, Rasi, and Rajendra Bhagwati. Based on response with regard to SPAD value, RLWC, and MSI the genotypes such as SRL 1, GPV 1, GPV 2, GPV 3, and Rajendra Mahsuri show positive increase compared to CSR 23 (Check). The inter-relationship concerning to various physiological parameters shows a strong significant and positive correlation among each other at tillering and pre-flowering stages. However, Total chlorophyll at the tillering stage was found to bear a highly significant correlation with all the physiological parameters except relative water content and membrane stability index. The genotypes such as SRL 1, GPV 1, GPV 2, and GPV 3, Rajendra Mahsuri possess better potential in sodic soil than the rest of the genotypes taken in the experiment with regard to various physiological parameters (taken as salt indices) by counteracting or minimizing the sodicity effect of sodium ion. The greater synthesis of antioxidant enzymes like catalase and peroxidase plays an important role in plant adaptation which effectively support to withstand and perform well in sodicity conditions hence SRL 1, GPV 1, GPV 2, GPV 3, and Rajendra Mahsuri categorized as salt tolerant genotypes which have great potential to boost up the rice production in sodic soil condition while Prabhat, Rasi and Rajendra Bhagwati categorized as salt susceptible genotypes. Thus, this study will be helpful for the identification of tolerant and susceptible genotypes through screening and pave way for the development of stable and high-yielding genotypes for the improvement of rice production under sodic soil.

Sorbitol and biochar have key roles in microbial and enzymatic activity of saline-sodic and calcareous soil in millet cropping.

Strengthening the microbial and enzymatic activities of the soil can be a way to increase the resistance of the plant to saline and sodic conditions. This research aimed to study the effect of sorbitol and biochar on improving the biological and chemical properties of saline and sodic soil in a millet cropping system. The field experiment was performed in a randomized block design with a factorial arrangement in three replications in field conditions. Experimental factors include three levels of sorbitol (S0: 0 t ha−1, S1.5: 1.5 t ha−1, and S3: 3 t ha−1) and two levels of sunflower stem biochar (B0: 0 t ha−1 biochar, B: 15 t ha−1 biochar). The results showed that sorbitol (S1.5, S3) and biochar increased microbial activity (BR and MBC) and soil enzymatic activity (DHA, ALP, UA, and CAT). Sorbitol had no significant effect on soil pH but reduced soil ECe (26%, 33%) compared to without sorbitol treatment. Sorbitol and biochar increased soil available nitrogen, available phosphorus, and dissolved organic carbon. 3 t ha−1 sorbitol increased millet yield by 50% more than 1.5 t ha−1 sorbitol and 72% more than biochar treatment. According to the results, using sorbitol and biochar in saline and sodic soil increased millet yield by improving the soil's biological and chemical properties.

Alleviation of Sodic Stress in Rice by Exploring the Exopolysaccharide-Producing Sodic-Tolerant Bacteria

Sodicity is one of the major salt stresses that impair crop production. Exopolysaccharide-producing sodic tolerant bacteria (EPS-STB) play a significant role in reducing the sodic stress in plants by hampering the uptake of sodium. In this context, this study aims to isolate the EPS-STB for alleviating sodic stress in rice under a sodic environment. Thus, artificial sodicity was created in culture media, and 253 bacteria were isolated from the rice rhizosphere of sodic soils in Trichy and Chinna Salem of Tamil Nadu in India. Fifty bacterial isolates were initially screened based on EPS production, sodic tolerant ability, and plant growth-promoting activities. Further, these bacterial isolates were identified using 16S rDNA sequencing. The results suggested that the isolated bacteria possessed biofilm-forming abilities along with plant growth-promoting activities and osmolyte accumulation under sodic stress conditions. Bacillus rugosus L1C7T, Bacillus paralicheniformis L1C5L, Pseudomonas sp. L5C14T and Franconibacter helveticus L2C1L2 were chosen as better EPS-STB plant growth-promoting bacteria, and their impact on rice under sodic conditions was evaluated. Among the sodic tolerant bacteria, Franconibacter helveticus L2C1L2-inoculated rice plants increased dry matter production compared to the control. Thus, this study showed that the utilization of EPS-STB will become a promising tool to alleviate sodic stress in rice.

Hotspot screening of early maturing rice genotypes and genetic variability studies under sodicity

An experiment was conducted with 39 rice genotypes to screen for salt tolerance and evaluate potential variation among the genotypes under sodic conditions. All the 39 rice genotypes along with two check varieties (TRY2 & TRY5) were screened in vitro for salt tolerance by imposing 100 mM NaHCO3 at the seedling stage under hydroponics and a salt injury score was given based on morphological symptoms. Observations on 12 biometrical traits were recorded under field sodic conditions and subjected to variability analysis. The ANOVA revealed that there was a significant difference for the 11 traits among the genotypes except for flag leaf breadth. Among the genotypes, the highest single plant yield was recorded by RG 50 (36.83 g). A  correlation study revealed that, single plant yield exhibited significant and positive genotypic and phenotypic relation with panicle harvest index, the number of grains per panicle and panicle length. Path analysis showed that the traits viz., panicle harvest index, plant height and panicle length had a very high and positive direct effect on single plant yield. The traits viz., flag leaf breadth, SPAD meter reading and number of productive tillers per plant had a high and positive direct effect on single plant yield. In vitro studies revealed that the genotype RG113 was found to be highly tolerant to salt stress and it also showed a significantly higher yield (35.42 g) under field sodicity. The genotypes RG22, RG150, RG162 and RG188 which showed tolerance under in vitro screening and the moderately tolerant genotypes RG26, RG50, RG95, RG107, RG123 and RG176 were exhibiting significant yield under field sodicity conditions. Therefore, in order to breed for high yielding salt-tolerant rice varieties, the identified genotypes could be exploited as donor genotypes. Keywords: Rice, correlation, path analysis, Hydroponics, sodicity  

Detection of calcium, magnesium, and chlorophyll variations of wheat genotypes on sodic soils using hyperspectral red edge parameters

Plants grown on sodic soils can suffer from macronutrient deficiencies, such as calcium (Ca), magnesium (Mg), and potassium (K), reducing health and growth. Nutrient concentrations in plant tissue could potentially provide a signal to identify cultivars tolerant to sodic conditions. However, conventional approaches to diagnosing crop nutrient and chlorophyll status involve determining total elemental content in plant tissues. These methods are time-consuming, tedious, and expensive, requiring destructive sampling of plant parts and complex laboratory analyses. Here, we propose a novel approach using hyperspectral sensing to determine macronutrient and chlorophyll variations/deficiencies of 18 different wheat genotypes grown in moderately sodic (MS) and highly sodic (HS) soil conditions in north-eastern Australia. Canopy reflectance was measured using a handheld spectroradiometer close to flowering to compute red edge spectral indices, such as normalized difference red edge index (NDRE), red edge inflection point (REIP), and red edge chlorophyll index (Cl rededge). Plant Ca, Mg, and K concentrations were also measured by destructive sampling of young mature leaves followed by laboratory analysis. The maximum first derivative of reflectance spectra for 18 wheat genotypes were observed at 722–728 nm and 719–725 nm for the MS and HS site, respectively and was used to determine REIP for the genotypes using a four-point linear interpolation method. Ca and Mg had a significant positive association with both REIP and NDRE, with Ca more closely correlated than either Mg or K. REIP was more closely associated with Ca (R2=0.72; RMSE=0.02 for the MS site and R 2=0.57; RMSE=0.02 for the HS site) than NDRE. This suggests that REIP has a great potential to detect structural variations of wheat genotypes in sodic soil environment. Furthermore, Ca was also significantly (p<0.0001) and positively correlated with Cl rededge at both sites with R2=0.53 and 0.51 for the MS and HS site. This suggests that plant structural variations in sodic soil can regulate leaf chlorophyll concentration and, in turn, photosynthetic activities. Overall, results demonstrate that hyperspectral sensing can be efficiently used to detect plant Ca, Mg, and chlorophyll concentrations. The study improves understanding of genotypic nutrient variation for tolerance to different levels of sodic soil conditions using optical properties of plant structure and can be beneficial to the plant science community for developing new approaches to study plant physiology.

Genetic Architecture and Association Studies for Grain Yield and its attributing Traits in Recombinant Inbred Lines for Sodicity Tolerance in Rice (Oryza sativa L.)

The present study was undertaken at NSP Unit 6 Agricultural Research Farm and Main Experimental Station of Acharya Narendra Dev University of Agriculture and Technology, Uttar Pradesh, India, from July to November 2020, in which genetic variability and heritability of 250 recombinant inbred lines (F7) and their parents PUSA 44 and CSR 43 were evaluated and correlation studies were performed for grain yield and yield contributing traits. The experiment was conducted in two replications at two different and naturally occurring sodic conditions following α-lattice design. Analysis of variance revealed significant variations among the lines depicting inherent variability between lines. For attributes, viz., plant height, effective tillers plant-1, spikelet fertility percentage, test weight and grain yield plant-1, high phenotypic and genotypic coefficient of variation estimates were observed for both the locations indicating good scope for selection based on these traits. However, the attributes viz., test weight and effective tillers plant-1 values depicted the pertinent role of the environment and thus, require careful assessment in selection programs concerning these traits. For days to 50% flowering, filled grains panicle-1, spikelet fertility percentage, and grain yield plant-1, moderate heritability was discovered with a high genetic advance as a percentage of mean, indicating that there is less influence of environment over these traits. Correlation studies revealed a significant and positive association with these yield attributing traits. Mutual association between component traits exhibit variable responses at both locations, validating genotype and environment interactions among traits with respect to yield.

Effect of different concentrations of foliar iron fertilizer on chlorophyll fluorescence characteristics of iron-deficient rice seedlings under saline sodic conditions

The effectiveness of iron is reduced in saline conditions, which can easily lead to iron deficiency and inhibit photosynthesis in rice. In this study, 4-week-old Fe-deficient rice seedlings were treated under saline sodic stress (50 mM) to different concentrations (0, 0.2%, 0.4%, 0.8%, 1.6%, and 3.2%) of foliar iron fertilizer (FeEDDHA). Differences in prompting fluorescence and the MR820 signal of rice leaves after 7 days of treatment were probed using the JIP-test. The results show that the performances of the two rice varieties were in general agreement. Under iron deficiency and soda salinity stress conditions, rice growth was inhibited, and the pigment content, specific energy flux, quantum yield, performance of the active PSII reaction center (PIABS) and the oxidation (Vox) and reduction rates (Vred) of PSI were reduced. These indicators first increase and then decrease with increasing iron fertiliser concentrations. The best results were obtained with the Fe3 treatment (0.8%). Fluorescence parameters such as the relative variable fluorescence (WK and VJ) and the quantum yield of energy dissipation (φDo) showed opposite trends. This suggests that iron deficiency/excess and soda saline stress disrupt the electron and energy transport in the photosystem. Appropriate iron fertilization concentration can repair the photosynthetic electron transport chain, improve electron transport efficiency and promote balanced energy distribution. Therefore, we suggest that moderate amounts of Fe are beneficial for improving the electron and energy transport properties of the photosystem, while spraying high concentrations of Fe fertilizer has a negative effect on improving salt tolerance in rice.

EVALUATION OF GUAVA GERMPLASM FOR GROWTH, QUALITY AND YIELD ATTRIBUTES SUITABLE UNDER SODIC SOIL CONDITIONS

Guava (Psidium guajava L.) popularly known as the "Apple of the Tropics", has gained considerable prominence on account of its high nutritive value, availability at moderate prices and pleasant flavour. It is a rich source of vitamin C and pectin, moderately good source of calcium and a fair source of phosphorus. The study was carried out to evaluate the guava (Psidium gujava L.) germplasm for growth, yield and quality under sodic soil condition. Totally 31 accessions of guava germplasm were collected and planted in RBD with 4 replications at Orchard, Horticultural College &amp; Research Institute for Women, Tamil Nadu Agricultural University, Trichy and evaluated for 5 years (2014 to 2018) under sodic condition. Growth observations on plant height (m), trunk circumference (cm), plant spread (E – W) (m) and plant spread (N – S) (m) and tree volume (cm3 ) were recorded. Further, yield and quality attributes viz., number of fruits tree-1, fruit length, fruit diameter, average fruit weight, fruit yield tree-1, pulp colour, flesh thickness, rind thickness and TSS were also recorded. Among the guava germplasm, “Surka Chitti Natputani” was found to be vigorous in growth habit followed by “Mirzapur seedling” whereas dwarfness and erect growth were observed in “Cheeni guava”. The accession “Nasik” recorded the highest fruit yield (26.285 kg tree-1) followed by “Mirzapur Seedling” (24.277kg tree-1). Dessert quality attributes viz., rind thickness, soft seed and total soluble solid were found to be best in “Allahabad Safed”. The present studies impart knowledge on morphological, quantitative variation and quality parameters of guava fruits and can be useful for producers, breeders, and processors. The salt tolerant genotypes having the capable of maintaining osmotic potential and providing more food materials.

Assessment of germination percentage and growth parameters of different varieties of Napiergrass (Pennisetum purpureum) on sodic soil of Thoothukudi district, Tamil Nadu, India

Napier grass (Pennisetum purpureum) is a fast-growing forage crop cultivated throughout the year in tropical and subtropical regions. A phytoremediation study was undertaken at the Agricultural College and Research Institute (AC &amp; RI), Killikulam, Thoothukudi District, Tamil Nadu, India, during 2020-2021 to evaluate the performance of cumbu napier varieties on sodic and neutral soil. Four cumbu napier varieties, CO (BN) 6, CO (BN) 5, KKM 1 and CO (CN) 4, were tested in both soils. Pots were filled with 10 kg of soil. Three cuttings of cumbu napiers per pot were planted as per the treatment schedule. Germination and growth parameters were observed up to three harvests. The results of the present study revealed that the germination percentage of variety CO (BN) 6 was highest (100%) among the varieties under sodic conditions. Growth parameters such as plant height, leaf length, number of leaves, and number of clumps of this variety showed better efficiency under high sodic levels than other varieties. This variety CO (BN) 6 could tolerate and be established well under alkaline soil and produced amaximum plant height (134 cm) and a higher number of clumps (10) during the third harvest. The growth pattern of cumbu napier varieties was in the order of CO (BN) 6&gt; CO (BN) 5 &gt; KKM 1 &gt; CO (CN) 4. Furthermore, the experimental results revealed that cumbu napier could be recommended as a suitable crop for sodic soil.

Mixing Sodium-Chloride-Rich Food Waste Compost with Livestock Manure Composts Enhanced the Agronomic Performance of Leaf Lettuce

Food waste generated at the consumer level constitutes a gigantic portion of the total amount of food wasted/lost and valorisation is touted as the most sustainable way of managing the generated waste. While food waste valorisation encompasses several methods, composting is the cheapest technique that can produce stabilised carbon-rich soil amendments. The food waste generated at the consumer level, however, is laden with sodium chloride. The compost produced from such waste has the potential of inducing saline and or sodic conditions in the soil, resultantly impeding proper crop growth and yield. Due to the scarcity of plausible means of eradicating sodium chloride from the food waste before composting, the idea of mixing the composted food waste with other low sodium chloride-containing composts to produce a food waste compost-containing amalgam with a high fertiliser potential was mulled in this study. The study then assessed the effects of mixing sodium-chloride-rich food waste compost with the nutritious and low sodium chloride-containing livestock manure composts on the yield and quality of leaf lettuce. Mixing food waste compost with livestock manure composts in the right proportions created mixed composts that produced a higher lettuce yield than both the pure livestock manure composts and food waste compost. The mixed composts also produced leaf lettuce with higher chlorophyll content and, thus, better marketability and lower nitrate content (with higher health value) than the pure livestock manure composts.

Identification of selection indices for the yield enhancement in cowpea (Vigna unguiculata (L.) Walp.) under sodic condition

The experiment was conducted at sodic soils to determine the relationship and degree of direct and indirect effects of yield and yield contributing traits in 57 cowpea accessions along with checks CO (CP) 7, VBN 1 and VBN 3. The association analysis showed that clusters number per plant, pod numbers per cluster, length of the pod, seeds per pod and hundred seed weight were positively correlated with seed yield. Path analysis indicated that the number of clusters per plant revealed a highly positive direct effect on single plant yield at genotypic level followed by pod length, pods number per cluster and seeds per pod. Principal Component Analysis (PCA) revealed first four PCs together contributed 67.33 per cent of variability. A total of 12 genotypes occupied the first quadrant showed better performance for five characters namely 100 seed weight, seed yield per plant, the number of clusters per plant, the number of pods per cluster and plant height. These selected genotypes namely IC 201075, EC 101989, EC 724750, EC 725166, CO 7, EC 724707, EC 121879, EC 101940, EC 101913, EC 724767, EC 107181 and EC 101928 could be used as donors or elite genotypes in cowpea yield improvement programmes. Key words: Correlation, cowpea, path analysis, PCA, sodicity