Plant Yield Research Articles

Functions of Basic Helix-Loop-Helix (bHLH) Proteins in the Regulation of Plant Responses to Cold, Drought, Salt, and Iron Deficiency: A Comprehensive Review.

Abiotic stresses including cold, drought, salt, and iron deficiency severely impair plant development, crop productivity, and geographic distribution. Several bodies of research have shed light on the pleiotropic functions of BASIC HELIX-LOOP-HELIX (bHLH) proteins in plant responses to these abiotic stresses. In this review, we mention the regulatory roles of bHLH TFs in response to stresses such as cold, drought, salt resistance, and iron deficiency, as well as in enhancing grain yield in plants, especially crops. The bHLH proteins bind to E/G-box motifs in the target promoter and interact with various other factors to form a complex regulatory network. Through this network, they cooperatively activate or repress the transcription of downstream genes, thereby regulating various stress responses. Finally, we present some perspectives for future research focusing on the molecular mechanisms that integrate and coordinate these abiotic stresses. Understanding these molecular mechanisms is crucial for the development of stress-tolerant crops.

Fine-mapping and validation of the major quantitative trait locus QFlANG-4B for flag leaf angle in wheat.

This study precisely mapped and validated a quantitative trait locus (QTL) located on chromosome 4B for flag leaf angle in wheat. Flag leaf angle (FLANG) is closely related to crop architecture and yield. We previously identified the quantitative trait locus (QTL) QFLANG-4B for FLANG on chromosome 4B, located within a 14-cM interval flanked by the markers Xbarc20 and Xzyh357, using a mapping population of recombinant inbred lines (RILs) derived from a cross between Nongda3331 (ND3331) and Zang1817. In this study, we fine-mapped QFLANG-4B and validated its associated genetic effect. We developed a BC3F3 population using ND3331 as the recurrent parent through marker-assisted selection, as well as near-isogenic lines (NILs) by selfing BC3F3 plants carrying different heterozygous segments for the QFLANG-4B region. We obtained eight recombinant types for QFLANG-4B, narrowing its location down to a 5.3-Mb region. This region contained 76 predicted genes, 7 of which we considered to be likely candidate genes for QFLANG-4B. Marker and phenotypic analyses of individual plants from the secondary mapping populations and their progeny revealed that the FLANG of the ND3331 allele is significantly higher than that of the Zang1817 allele in multiple environments. These results not only provide a basis for the map-based cloning of QFLANG-4B, but also indicate that QFLANG-4B has great potential for marker-assisted selection in wheat breeding programs designed to improve plant architecture and yield.

Impact of Soil-Applied Thyme Oil on Strawberry Yield and Disease Abundance

ABSTRACT Strawberry growers across the United States are looking for sustainable alternatives to conventional pesticides for management of soil-borne or crown-rot causing pathogens, such as plant-extracts like thyme oil. The objectives of this study were to determine the impact of soil-applied thyme oil fungicides on strawberry plant health, yield, sweetness, and foliar disease, and on the assemblage of soil microbial communities in strawberry plasticulture systems. In 2021 and 2022 the interaction of three soil-applied fungicides and three foliar fungicide programs were explored. Thyme oil was not found to improve strawberry plant growth or yield when compared to strawberries in the control. However, plants treated with mefenoxam exhibited an average winter crown weight of 2.11 g, significantly lower than control and thyme oil treatments at 3.14 g and 3.16 g, respectively. This translated into a significant yield loss where mefenoxam treated plants exhibited lowered yields at 416.04 g of fruit per plant compared to 523.57 g and 521.53 g per plant in the control and thyme oil treatments, respectively. A high incidence of foliar and fruit diseases was present; however, no interaction of soil and foliar fungicide treatments were observed for yield or fruit sweetness. Minimal root protection from pathogens was observed for all treatments and Fusarium, Pythium and Phytophthora fungi were regularly observed. Mefenoxam was observed to increase the recovery of oomycetes, which may cause Pythium and Phytophthora. No benefit from thyme oil was observed at our site and its addition as a soil fungicide would likely not benefit most growers.

Joint transcriptomic and metabolomic analysis provides new insights into drought resistance in watermelon (Citrullus lanatus)

IntroductionWatermelon is an annual vine of the family Cucurbitaceae. Watermelon plants produce a fruit that people love and have important nutritional and economic value. With global warming and deterioration of the ecological environment, abiotic stresses, including drought, have become important factors that impact the yield and quality of watermelon plants. Previous research on watermelon drought resistance has included analyzing homologous genes based on known drought-responsive genes and pathways in other species.MethodsHowever, identifying key pathways and genes involved in watermelon drought resistance through high-throughput omics methods is particularly important. In this study, RNA-seq and metabolomic analysis were performed on watermelon plants at five time points (0 h, 1 h, 6 h, 12 h and 24 h) before and after drought stress.ResultsTranscriptomic analysis revealed 7829 differentially expressed genes (DEGs) at the five time points. The DEGs were grouped into five clusters using the k-means clustering algorithm. The functional category for each cluster was annotated based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database; different clusters were associated with different time points after stress. A total of 949 metabolites were divided into 10 categories, with lipids and lipid-like molecules accounting for the most metabolites. Differential expression analysis revealed 22 differentially regulated metabolites (DRMs) among the five time points. Through joint analysis of RNA-seq and metabolome data, the 6-h period was identified as the critical period for watermelon drought resistance, and the starch and sucrose metabolism, plant hormone signal transduction and photosynthesis pathways were identified as important regulatory pathways involved in watermelon drought resistance. In addition, 15 candidate genes associated with watermelon drought resistance were identified through joint RNA-seq and metabolome analysis combined with weighted correlation network analysis (WGCNA). Four of these genes encode transcription factors, including bHLH (Cla97C03G068160), MYB (Cla97C01G002440), HSP (Cla97C02G033390) and GRF (Cla97C02G042620), one key gene in the ABA pathway, SnRK2-4 (Cla97C10G186750), and the GP-2 gene (Cla97C05G105810), which is involved in the starch and sucrose metabolism pathway.DiscussionIn summary, our study provides a theoretical basis for elucidating the molecular mechanisms underlying drought resistance in watermelon plants and provides new genetic resources for the study of drought resistance in this crop.

Integrated Nutrient Management in Muskmelon: A Comprehensive Field Study

The present study aims to describe the effects of integrated nutrient management (INM) on Madhumita variety of muskmelon cultivation in terms of plant growth, fruit yield, and quality. The experiment has been carried out in the crop field located in the North Konkan region of Maharashtra, India. This case study involved seven different treatments (T1 to T7), each with varying nutrient application regimes. Certain observational data, such as vine length, number of leaves per plant, leaf length, days to 50% flowering, number of fruits per plant, fruit length, fruit width, fruit weight, and fruit yield, were recorded for three replications over the course of the experiment. The results of statistical analysis revealed significant differences, with specific treatments demonstrating T6, which included Vermicompost at 5 tons/ha, 75% of the recommended dose of fertilizers (RDF), and 1% NOVEL prime organic liquid nutrient, consistently outperformed the other treatments groups. The findings highlight the utility of integrated nutrient management. It helps in understanding and optimizing the application of nutrients to boost crop productivity and promote sustainability.

N-acetylcysteine absorption and its potential dual effect improve fitness and fruit yield in Xylella fastidiosa infected plants.

Xylella fastidiosa is a multi-host bacterium that can be detected in hundreds of plant species including several crops. Diseases caused by X. fastidiosa are considered a threat to global food production. The primary method for managing diseases caused by X. fastidiosa involves using insecticides to control the vector. Hence, it is necessary to adopt new and sustainable disease management technologies to control not only the insect but also the bacteria and plant health. We demonstrated that N-acetylcysteine (NAC), a low-cost cysteine analogue, is a sustainable molecule that can be used in agriculture to decrease the damage caused by X. fastidiosa and improve plant health. Using 15N-NAC we proved that this analogue was absorbed by the roots and transported to different parts of the plant. Inside the plant, NAC reduced the bacterial population by 60-fold and the number of xylem vessels blocked by bacterial biofilms. This reflected in a recovery of 0.28-fold of the daily sap flow compared to health plants. In addition, NAC-treated citrus variegated chlorosis (CVC) plants decreased the oxidative stress by improving the activity of detoxifying enzymes. Moreover, the use of NAC in field conditions positively contributed to the increase in fruit yield of CVC-diseased plants. Our research not only advances the understanding of NAC absorption in plants, but also indicates its dual effect as an antimicrobial and antioxidant molecule. This, in turn, negatively affects bacterial survival while improving plant health by decreasing oxidative stress. Overall, the positive field-based evidence supports the viability of NAC as a sustainable agricultural application. © 2024 Society of Chemical Industry.

Productive Specialty Eggplant Cultivars Suitable for Small Farms in the Southeastern Coastal Plain

Specialty eggplants (Solanum melongena L.), cultivars with fruit shapes, sizes, and colors different from the typical teardrop-shaped, dark purple eggplant fruit, are an underproduced vegetable commodity in the southeastern United States. Seven cultivars representing seven different fruit types were grown in Charleston, SC, USA, in Spring and Fall 2018 and 2019 to assess cultivar productivity and net return. Despite year-to-year variability, Hansel (Chinese type), Millionaire (Japanese type), and Gretel (white fruit) generally had greater weights of both marketable (US Fancy and No. 1 fruit) and edible (US Fancy, No. 1 and No. 2) fruit than Fairy Tale (Sicilian type) and Patio Baby (Indian type), whereas the globe-fruited cultivars Black Beauty (heirloom) and Rosa Bianca (Italian type), had intermediate yields. Yields of plants after ratooning in the fall were lower than in the spring before ratooning. Prices per carton paid by local food hubs for US Fancy, No. 1, and No. 2 fruit were two to three times greater than wholesale terminal market prices. Nevertheless, fruit weights were a greater determinant of net returns than prices were. Growers in the southeastern coastal plain can maximize net returns from specialty eggplant crops by choosing cultivars that produce high fruit weights.

Physiological responses, ion accumulation and yield performance of wheat (Triticum aestivum L.) to salt stress

Wheat is affected by various biotic and abiotic stresses, especially salinity, which reduces the growth and yield drastically. High salinity is a major constraint for wheat productivity in many countries, including Bangladesh. With this view, here, an experiment was conducted to observe genotypic differences in physiological, ion accumulation, agro-morphological and yield performance of wheat against different levels of salinity. Experimental variables consisted of five salt tolerant genotypes (G 20–2–2, G 20–1–2, G 13–2, G 22–2, G 9–2), one susceptible genotype (G 24–2) and one standard check variety (BARI ghom 25), which assigned to four levels of salinity with electrical conductivities control (0.3), 4, 8 and 12 dS m−1. Irrespective of genotypes, salinity stress significantly decreased the yield and yield attributes. Results of analyses based on salt tolerance indices of plant growth related and yield contributing parameters, ionic balance (Na+, K+ and Na+ /K+ ratio), and stress indicators such as chlorophyll content, photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) revealed genotypes G 20–2–2, G 13–2 and G 20–1–2 as salt tolerant, genotype G 9–2 as moderately salt-tolerant and G 24–2 and G 22–2 as salt-sensitive genotypes. Additionally, lower accumulations of hydrogen peroxide and malondialdehyde, and higher activities of antioxidant enzymes in the salt-tolerant genotypes G 20–2–2 and G 13–2 than in the salt-sensitive genotype G 24–2 indicated reduced oxidative damage in genotypes G 20–2–2 and G 13–2 relative to that in genotype G 24–2. Collectively, our findings suggest that the optimum growth and yield of salt tolerant genotypes are associated with decreased Na+/K+ ratio, increased antioxidant enzymes activity and reduced oxidative stress.

Enhancing bioelectricity generation and mitigating methane emissions in paddy fields: A novel approach using activated biochar in plant microbial fuel cells

In the innovative realm of green energy solutions, plant microbial fuel cells (PMFCs) have emerged as a promising frontier, embodying a greener technological approach. However, PMFC is not yet viable for large-scale application due to its low voltage generation. This study explores the integration of PMFC technology in paddy field, using activated biochar as electrode material to enhance voltage production while reducing methane emission. According to the findings, rice PMFCs equipped with activated biochar achieved the highest power density, reaching an impressive 106.67 mW m−2 of anode area, significantly outperforming SMFCs, which peaked at 38.28 mW m−2 when integrated with a biochar anode. Additionally, rice-PMFCs emitted 38 % less methane than the normal rice plant, while the reduction was 27.1 % for rice plants equipped with activated biochar, with no significant change in plant yield observed. Furthermore, PMFCs reduced greenhouse gas emissions by 70 % and 67 % compared to traditional coal and natural gas-based power plants, respectively. In summary, activated biochar shows promise as a potent alternative to traditional graphite electrodes in PMFCs.

Improvement of morphophysiological and anatomical attributes of plants under abiotic stress conditions using plant growth-promoting bacteria and safety treatments.

Drought and salinity are the major abiotic stress factors negatively affecting the morphophysiological, biochemical, and anatomical characteristics of numerous plant species worldwide. The detrimental effects of these environmental factors can be seen in leaf and stem anatomical structures including the decrease in thickness of cell walls, palisade and spongy tissue, phloem and xylem tissue. Also, the disintegration of grana staking, and an increase in the size of mitochondria were observed under salinity and drought conditions. Drought and salt stresses can significantly decrease plant height, number of leaves and branches, leaf area, fresh and dry weight, or plant relative water content (RWC%) and concentration of photosynthetic pigments. On the other hand, stress-induced lipid peroxidation and malondialdehyde (MDA) production, electrolyte leakage (EL%), and production of reactive oxygen species (ROS) can increase under salinity and drought conditions. Antioxidant defense systems such as catalase, peroxidase, glutathione reductase, ascorbic acid, and gamma-aminobutyric acid are essential components under drought and salt stresses to protect the plant organelles from oxidative damage caused by ROS. The application of safe and eco-friendly treatments is a very important strategy to overcome the adverse effects of drought and salinity on the growth characteristics and yield of plants. It is shown that treatments with plant growth-promoting bacteria (PGPB) can improve morphoanatomical characteristics under salinity and drought stress. It is also shown that yeast extract, mannitol, proline, melatonin, silicon, chitosan, α-Tocopherols (vitamin E), and biochar alleviate the negative effects of drought and salinity stresses through the ROS scavenging resulting in the improvement of plant attributes and yield of the stressed plants. This review discusses the role of safety and eco-friendly treatments in alleviating the harmful effects of salinity and drought associated with the improvement of the anatomical, morphophysiological, and biochemical features in plants.

Effect of ethyl methane sulphonate on growth, yield and some physiological parameters of Bambara groundnut (Vigna subterranea (L.) verdc) in non - water stressed and water stressed conditions

Bambara groundnut (Vigna subterranea (L.) Verdc.) is a legume cultivatd majorly for it’s seeds and commonly grown by subsistence farmers in sub-Saharan Africa. In order to determine the effect of ethyl methane sulphonate (EMS) mutagen on the growth, yield and some physiological parameters of non-water stressed (NWS) and water stressed (WS) bambara groundnut. It’s seeds were treated with five concentrations (0.00 (control), 0.25, 0.50, 0.75 and 1.00% v/v) Ethyl methane sulphonate and were grown under two conditions: non-water stressed and water stressed. Analysis of variance (ANOVA) revealed significant differences (P ≤ 0.50) in the emergence percentage (6 DAS), germination percentage (7 DAS), plant height (PH), number of leaves per plant (NL), leaf length (LL), leaf width, (LW), relative water content (RWC), chlorophyll a, b and total chlorophyll contents in the non-water stressed and water stressed plants. After rewatering at 8 WAS, highest number of leaves in NWS and WS conditions were observed in 0.75% EMS concentration (229, 189), highest leaf length in NWS and WS plants were observed in 0.50% EMS concentration (9.47cm, 9.13cm). Highest leaf width in NWS and WS plants was observed in 0.25% EMS concentration (4cm, 3.63cm). Highest number of pods per plant (NP) and weight of pods per plant (WP) were observed in 0.75% EMS concentration only in NWS plants. Highest chlorophyll a, b and total chlorophyll content was observed in 1.00% EMS concentration. The result form this study showed that Ethyl methane sulphonate (EMS) mutagen concentration increased the growth, yield and physiological parameters of Bambara groundnut in non-water stressed condition at different doses, however there was no positive effect of EMS on yield in the water stressed plants.

INDIGENOUS CUCURBITS AND GRAFTING TECHNIQUES AFFECT CUCUMBER’S PRODUCTIVITY BY MODULATING MORPHO-PHYSIO-BIOCHEMICAL INDICES

Vegetable grafting is a unique surgical horticultural technology for inducing soilborne biotic and abiotic stress tolerance in cucumbers. Indigenous cucurbit germplasm as rootstocks may show more tolerance potential compared to exotic ones. However, it needs evaluation for compatibility testing through various grafting techniques. Therefore, this study was planned to test available cucurbits as rootstocks for graft success vis-à-vis cucumber growth and productivity. It was carried out in plant propagation and physiological lab MNS University of Agriculture Multan. The seeds of the indigenous open-pollinated cucurbits were sown in 64-celled plug trays having peat moss as growing media followed by shifting to 50-celled plug trays at first true leaf emergence stage. The seeds of selected scion (cucumber) were sown after the emergence of rootstock seeds. Different grafting techniques were performed at first true leaf stage of the scion followed by healing, and acclimatization. In this experiment, hybrid cucumber (cv Yalla F1) was grafted on three indigenous cucurbits namely ridge gourd (Luffa acutangular), bottle gourd (Lagenaria sicearia) and pumpkin (Cucurbit pepo. L) for graft compatibility success by using three grafting techniques: cleft grafting, one cotyledon grafting and hole insertion. Non-grafted cucumber was grown to compare with grafted plants for growth, and productivity. Overall, significant (p ≤ 0.5%) results were  obtained in terms of 90% survival rate in cucumber plants grafted onto  the bottle gourd through cleft grafting as compared to the other grafting techniques. Additionally, the cucumber plants grafted on bottle gourd showed the highest morphological (root length, shoot length, root fresh weight, shoot fresh weight, amd rootstocks, and scion girth), physiological (photosynthetic rate, transpiration rate, stomatal conductance, and sub-stomatal conductance), biochemical (antioxidants activities, SOD, CAT, and POX) and yield indices (average fruit length, weight, numbers, and yield) as compared to the non-grafted plants.  Conclusively, cucumber grafting onto indigenous bottle gourd with cleft grafting technique exhibited maximum compatibility confirmed through physio-chemical attributes and improved in plants biomass and yield, thereby suggested for cucumber grafting.

Expressing banana transcription factor MaERFVII3 in Arabidopsis confers enhanced waterlogging tolerance and root growth.

Waterlogging poses a significant threat to plant growth and yield worldwide. Identifying the genes responsible for mitigating waterlogging stress is crucial. Ethylene-responsive factors (ERFs) are transcriptional regulators that respond to various biotic and abiotic stresses in plants. However, their roles and involvement in responding to waterlogging stress remain largely unexplored. Hence, this study aimed to elucidate the role of ERFs in enhancing banana plant resilience to waterlogging. We hypothesized that introducing a group VII ERF transcription factor in Arabidopsis could enhance waterlogging stress tolerance. To test this hypothesis, we isolated MaERFVII3 from banana roots, where it exhibited a significant induction in response to waterlogging stress. The isolated MaERFVII3 was introduced into Arabidopsis plants for functional gene studies. Compared with wild-type plants, the MaERFVII3-expressing Arabidopsis showed increased survival and biomass under waterlogging stress. Furthermore, the abundance of transcripts related to waterlogging and hypoxia response showed an elevation in transgenic plants but a decrease in wild-type and empty vector plants when exposed to waterlogging stress. Our results demonstrate the significant contribution of MaERFVII3 to waterlogging tolerance in Arabidopsis, providing baseline data for further exploration and potentially contributing to crop improvement programs.

A Systematic Review on Effects of Nitrogen Fertilizer Levels on Cabbage (Brassica oleracea var. capitata L.) Production in Ethiopia

Cabbage (Brassica oleracea var. capitata L.) holds significant agricultural and nutritional importance in Ethiopia; yet, its production faces challenges, including suboptimal nitrogen fertilizer management. The aim of this review was to review the possible effect of nitrogen fertilizer levels on the production of cabbage in Ethiopia. Nitrogen fertilization significantly influences cabbage yield and quality. Moderate to high levels of nitrogen application enhance plant growth, leaf area, head weight, and yield. However, excessive nitrogen levels can lead to adverse effects such as delayed maturity, increased susceptibility to pests and diseases, and reduced postharvest quality. In Ethiopia, small-scale farmers use different nitrogen levels for cabbage cultivation. In Ethiopia, NPSB or NPSBZN fertilizers are widely employed for the growing of various crops such as cabbage. 242 kg of NPS and 79 kg of urea are the blanket recommendation for the current production of cabbage in Ethiopia. The existing rate is not conducive for farmers. Therefore, small-scale farmers ought to utilize an optimal and cost-effective nitrogen rate to boost the cabbage yield. Furthermore, the effectiveness of nitrogen fertilization is influenced by various factors including the soil type, climate, cabbage variety, and agronomic practices. Integrated nutrient management approaches, combining nitrogen fertilizers with organic amendments or other nutrients, have shown promise in optimizing cabbage production while minimizing environmental impacts. The government ought to heed suggestions concerning soil characteristics such as the soil type, fertility, and additional factors such as the soil pH level and soil moisture contents.

Response of late-sown wheat (Triticum aestivum) to limited irrigation, seed rate and depth of sowing

A field experiment was conducted during the winter (rabi) season of 2014–15 and 2015–16 at New Delhi, to study the effect of limited irrigation, seed rate and depth of sowing on growth, yield, water-use parameters and economics of late-sown wheat (Triticum aestivum L.). The experiment comprised 3 factors, viz. 3 irrigation levels [(I1 , irrigation at crown-root initation (CRI) stage; I2 , irrigation at CRI stage + 0.2 irrigation water: cumulative pan evaporation (IW : CPE) ratio; and I3, irrigation at CRI stage + 0.4 IW : CPE ratio), 3 seed rates (S1, 75; S2, 100 and S2, 125 kg/ha) and 2 depths of sowings (D1, 5 cm and D2 , 10 cm). The field experiment comprising 18 treatment combinations, replicated thrice, was laid out in strip-plot design. Interactions between irrigation levels and seed rates, and irrigation levels and depths of sowing for grain yield were significant during 2014–15. Irrigation levels, seed rates and depths of sowing also significantly affected plant height, yield attributes, grain yield, straw yield and harvest index. Irrigation at CRI stage + 0.4 IW : CPE ratio resulted in significantly the highest plant height (86.3 cm), effective tillers/m2 (407.82), spike length (14.40 cm), spikelets/spike (17.43), grains/spike (44.20), grain weight/spike (2.05 g), 1,000-grain weight (48.95 g), grain yield (4.22 and 3.75 t/ha during 2014–15 and 2015–16) and harvest index (0.497 and 0.477 during respective season). Seed rate of 125 kg/ha resulted in significantly the highest plant height (82.7 cm), effective tillers/m2 (416.66), spike length (14.62 cm), spikelets/spike (17.53), grains/ spike (40.20), grain weight/spike (2.06 g), 1,000-grain weight (47.80 g), grain yield (3.63 t/ha during 2015–16) and harvest index (0.496 and 0.456 during respective year). Sowing depth of 10 cm resulted in significantly the highest plant height (82.2 cm), effective tillers/m2 (382.64), spike length (13.94 cm), spikelets/spike (16.44), grains/spike (38.21), grain weight/spike (1.90 g), 1,000-grain weight (46.24 g), grain yield (3.95 and 3.49 t/ha during both the years) and harvest index (0.456 and 0.443 during both the years).

Studies on the Impact of Microbial Consortia towards Enhancing the Growth of Red Sanders

The use of plant growth-promoting microorganisms, either alone or combined, as bioinoculants presents an economical and eco-friendly alternative to chemical fertilizers. This method provides a comprehensive solution for enhancing plant growth and yield. This study aimed to develop robust microbial consortia possessing plant growth-promoting capabilities and evaluate their effectiveness in enhancing tree seedling growth. Six bacterial strains were collected and screened for specific traits linked to promoting plant growth. Selected strains were then assessed for compatibility with each other, resulting in the formation of bacterial consortia. These consortia demonstrated diverse plant growth-promoting properties, including the production of the plant growth hormone indole acetic acid and the synthesis of exopolysaccharides. Consequently, these bacterial consortia exhibit significant potential as bioinoculants, offering a promising approach to enhancing plant growth and productivity in an environmentally friendly manner. This contributes to the progress of efforts aimed at promoting seedling growth.

Effect of live mulches, cover crops and herbicides on weed flora, growth and yield of direct-seeded rice (Oryza sativa)

Effect of live mulches, cover crops and herbicides on weed flora, growth and yield of direct-seeded rice (Oryza sativa)

Association Analysis in Rice Germplasm Lines for High Temperature Tolerance

Background: Relative to other abiotic factors like salinity and drought, breeding rice cultivars that are resistant of high temperatures has received a little attention. The purpose of this study is to find parents and genotypes that are suitable for utilizing in high temperature stress breeding program. Methods: The genetic material for this study comprised of a set of germplasm collections (293 accessions) from different sources such as International Rice Research Institute germplasm. These populations were raised at the Department of Rice, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore. The Heat tolarance Indices (TOL) viz., Heat tolerance index (HTI) and Heat susceptibility index (HSI) and association analysis were estimated among germplasm lines for yield attributes under normal and high temperature stress condition. Result: Out of 293 genotypes, sixty nine genotypes significantly exceeded for both HTI and HSI. Association studies revealed that, single plant yield had highly significant and positive association with panicle exertion, number of total tillers per plant, number of productive tillers per plant, panicle length, number of filled grains per panicle and total dry matter production. Spikelet sterility and high temperature susceptibility index had highly significant and negative association with single plant yield. Number of productive tillers had significant and positive correlation with total dry matter production, panicle length, number of filled grains per panicle, days to maturity, hundred grain weight, grain breadth and high temperature susceptible index. Hence these traits may be considered as selection indices for yield and high temperature tolerance improvement programme. Hence it may be possible to combine single plant yield and heat susceptibility index by specific breeding programme for high temperature tolerance in rice.

Alpha lipoic acid mitigates adverse impacts of drought stress on growth and yield of mungbean: photosynthetic pigments, and antioxidative defense mechanism.

Exogenous use of potential organic compounds through different modes is a promising strategy for the induction of water stress tolerance in crop plants for better yield. The present study aimed to explore the potential role of alpha-lipoic acid (ALA) in inducing water stress tolerance in mungbean lines when applied exogenously through various modes. The experiment was conducted in a field with a split-plot arrangement, having three replicates for each treatment. Two irrigation regimes, including normal and reduced irrigation, were applied. The plants allocated to reduced irrigation were watered only at the reproductive stage. Three levels of ALA (0, 0.1, 0.15 mM) were applied through different modes (seed priming, foliar or priming+foliar). ALA treatment through different modes manifested higher growth under reduced irrigation (water stress) and normal irrigation. Compared to the other two modes, the application of ALA as seed priming was found more effective in ameliorating the adverse impacts of water stress on growth and yield associated with their better content of leaf photosynthetic pigments, maintenance of plant water relations, levels of non-enzymatic antioxidants, improved activities of enzymatic antioxidants, and decreased lipid peroxidation and H2O2 levels. The maximum increase in shoot fresh weight (29% and 28%), shoot dry weight (27% and 24%), 100-grain weight (24% and 23%) and total grain yield (20% and 21%) in water-stressed mungbean plants of line 16003 and 16004, respectively, was recorded due to ALA seed priming than other modes of applications. Conclusively, 0.1 and 0.15 mM levels of ALA as seed priming were found to reduce the adverse impact of water stress on mungbean yield that was associated with improved physio-biochemical mechanisms. The findings of the study will be helpful for the agriculturalists working in arid and semi-arid regions to obtain a better yield of mungbean that will be helpful to fulfill the food demand in those areas to some extent.

Effects of concentration and time of brassinosteroid treatment on growth and yield of soybean under drought stress conditions

Soybean (Glycine max (L.) Merrill.) is an essential food and industrial crop, but it can be heavily affected by drought, especially during the pod growth stage. Brassinosteroids (BRs) are reported to alleviate drought stress, but the effectiveness may depend strongly on BR concentration and timing of the application, and no research has investigated this issue. This study aimed to determine the suitable concentration of BRs and time of treatment to help soybean plants withstand drought conditions during pod growth. The experiment was conducted with a completely randomized design, with four concentrations of BRs: 0 ppm (water) (B0), 0.1 ppm (B1), 0.2 ppm (B2), 0.3 ppm (B3), and three-time points for the application of BR treatment: soaking before sowing (T1), leaf spray when 50% of plants flowered (T2), leaf spray when 50% of the plants had pod at least 0.5 cm in length (T3). The results showed that when treated with different concentrations and treatment times of BRs, there was no difference in plant growth and development. However, there were differences in the yield of soybean plants. Specifically, treatment B2T2 had the highest total number of firm pods and the highest number of firm seeds at 22.2 and 44.6, respectively, with the weight of 100 seeds reaching 17.9 g, leading to the highest actual yield of 97.0 g/plot. These results indicate that with appropriate concentration and timing (0.2 ppm during flowering), the application of BRs can significantly alleviate drought stress effects on soybean plants during pod growth, improving seed yield and quality.