Dhashnamurthi Vijayalakshmi

• Tamil Nadu Agricultural University

Waterlogging is a significant abiotic stressor that severely hampers sugarcane productionworldwide. To address this issue, experiments were conducted at the Sugarcane Research Station, Cuddalore, (TNAU), during 2022-2023 to evaluate the waterlogging tolerance of sugarcane clones.The experiment followed a factorial completely randomized design (FCRD...

Pre-harvest sprouting (PHS) poses a persistent threat in rice growing regions. Tamil Nadu, is often prone to unexpected rains before harvest, aggravating the PHS. This study aimed to evaluate the genetic variability of PHS in popular rice varieties of Tamil Nadu, assess the effectiveness of chemical treatments and growth retardants in controlling P...

Foxtail millet is an early maturing crop and has high water use efficiency, suitable for arid and semi-arid regions. Climate models predicted that the average rise in global temperature will be 1.5 ? in the next two decades. There will be an altered rainfall pattern along with a high occurrence of heat waves in foxtail millet growing regions. There...

Altered environmental conditions subject plants to abiotic stresses like salinity, drought, temperature fluctuations (heat and cold) and exposure to heavy metals. Frequent stresses prompt the plant defense system to consistently adapt. Biostimulants assist plants in refining their defense strategies, allowing more effective responses to the changin...

As climate change intensifies, drought stress presents a critical challenge for horticultural crops like okra (Abelmoschus esculentus). The effectiveness of melatonin in reducing drought stress is investigated in this study. The treatments include: Absolute control (fully irrigated), control (drought), drought and seed treatment with 100 µM melaton...

The foliar application of nutrients and plant growth regulators (PGRs) at critical crop growth periods can improve the yield of field crops. Hence, the present study was conducted to quantify the effects of the combined application of nutrients and PGRs (crop-specific formulation) on maize, blackgram, greengram, groundnut, cotton, sugarcane, and co...

Sorghum (Sorghum bicolor [L.] Moench) is the fifth most important cereal grown mostly in arid and semi-arid regions. Climate models predict that there is a risk of drought stress in those regions. Quantifying the physiological traits for developing the tolerant lines is efficient but time-consuming process. Therefore, it is necessary to find a rapi...

Good seed germination is prerequisite for direct seeded rice cultivation to withstand anaerobic conditions. In transplanted rice cultivation, major constrains are labour cost and huge water requirements. To overcome these problems, development of rice varieties with anaerobic germination tolerance is mandatory. Hence, the study evaluated 99 rice la...

Rice (Oryza sativa L.) is susceptible to drought or high-temperature stress, and the response of rice to combined drought and high-temperature stress was not studied in detail under field condition. Moreover, rice will be susceptible to combined drought and high-temperature stress during its sensitive phases. Melatonin is recognized as a multifunct...

Chilli (Capsicum annum L.) is a vegetable crop that is valued for its colour and pungency. Water scarcity with high temperature has serious impact on growth, development and reproduction of crops. However, knowledge on the impact of combined stress on chilli physiology and reproduction is limited. Thus, the present study aims to assess the combined...

Rice is the world's third most important food crop, particularly in Asia. Drought stress has varying degrees of impact on its production. New plant growth regulators have been studied in recent years as a way to overcome physiological limitations and increase productivity. Melatonin has been investigated for its potential advantages in boosting pla...

Background: Anaerobic conditions in waterlogged soil affect germination rate significantly reducing rice yields. Under wet direct seeded condition, only limited availability of rice genotypes are suitable for anaerobic germination. So, there is an urgent need to identify rice genotypes for enhanced germination even under anoxic stress. Methods: Exp...

This study addresses a knowledge gap in understanding the interaction effect of nutrient-plant growth regulators on groundnut which plays a vital role in morpho-physiological processes for achieving enhanced productivity. The main goal was to evaluate how different nutrio-hormonal combinations affect groundnut traits. The experiment was conducted i...

Climate change has increased environmental risks globally having an adverse effect on agriculture productivity. Among the abiotic stresses, anaerobic germination stress has been identified as a major stress for seed emergence, plant growth and food production. By understanding the manipulation of germination, antioxidant and fermentation enzymes, a...

Salinity, a prominent abiotic stressor, profoundly influences the growth and development of rice plants. In this study, 26 genotypes, accompanied by two control varieties, underwent screening for salinity tolerance at the seedling stage through hydroponics. Analysis of variance unveiled significant variations among genotypes in the recorded traits....

The decline of soil nutrient status and productivity of crops, and restoration of soil health is a key global concern. Crop yields are reduced by soil degradation, which endangers the world's food supply. Crop yields and soil health are further decreased by improper fertilizers use in conjunction with intense cropping. A wide variety of plants, par...

In tomato (Lycopersicon esculentum L.), the effects of combined drought (D) and high temperature (HT) stress during the flowering stage had not been studied in detail. Therefore, this study was conducted with an objective of quantifying the effects of foliar spray of melatonin under individual and combined drought and HT stress. At flowering stage,...

Increase in carbon-dioxide (CO2) concentration along with increase in temperature and drought has significant impact on the crop production. Thus, the aim of the study was to investigate the individual and interactive effects of elevated CO2 (800 ppm), drought (50% field capacity) and heat (40 °C) on gas exchange parameters, membrane integrity, rep...

The decline of soil nutrient status and productivity of crops, and restoration of soil health is a key global problem. Crop yields are reduced by soil degradation, which endangers the world's food supply. Crop yields and soil health are further decreased by improper fertilizers in conjunction with intense cropping. A wide variety of plants, particu...

In crops, drought stress reduces the photosynthetic rate and gamete function through oxidative damage. Earlier studies showed that nanoceria possesses an antioxidant property; however, the ability of nanoceria to alleviate drought-stress-stimulated oxidative damage in pulse crops has not been studied. Therefore, experiments were conducted to assess...

Complete submergence is one of the most important abiotic stress constraining rice production in India. From the past few decades effect of this stress has intensified and is anticipated to increase in coming years as a result of global climate change. Rice has developed many adaptive mechanisms to grow well in flood ecosystems however, too much wa...

The experiment was carried out to assess the following objectives: (i) To understand the effect of drought stress on plant height and leaf area in diverse sorghum genotypes. (ii) To study the alterations in chlorophyll index and yield components under drought stress. (iii) To correlate yield with all morpho-physiological traits to understand drough...

Floods can completely submerge rice fields. When rice is submerged, various anatomical and physiological changes occur at cellular and whole plant levels. New submergence tolerant varieties have been developed for the benefit of farmers in flooded areas. The present investigation comprised of evaluating a Sub 1introgressed CO 43 variety (CO 43 Sub...

High temperature causes alteration in physiological and yield parameters of mulberry plant. The present study was conducted to examine the tolerance/ susceptibility of five popularly cultivated mulberry varieties viz., V1, G2, G4, MR2 and S36 exposed to high temperature stress. The varieties were maintained in Open Top Chambers (OTCs) at 40 ºC for...

Rice is well adapted to a wide range of climates, but is highly susceptible to heat during flowering. However, there are uncertainties in assessing the occurrence of heat-induced spikelet sterility (HISS) and the impact of climate change. One reason is the gap between the ambient air temperature and the panicle temperature, which determines the mag...

The grain filling of rice is gets weakened by heat stress due to reduced spike photosynthesis at high temperature stress. An alternate source of carbon is stored stem reserves for grain filling. Rate of stem dry matter, translocation efficiency (TE) and contribution rate (CR), grain yield were monitored under control and high temperatures in the gr...

The present study was under taken to assess the drought stress tolerance in four mulberry genotypes and three varieties. Four months old mulberry plants were subjected to three water regimes viz., 100% PC, 50% PC, 25% PC for 30 days. Chlorophyll Stability Index, intrinsic Water Use Efficiency and osmolyte accumulation (proline content) were estimat...

Heat waves and droughts are projected to become more widespread as a result of climate change. At the same time, CO2 levels are predicted to have doubled by 2100. The stomatal regulation and gas exchange characteristics were assessed in 25 days old plants of green gram (var Co 8) by exposing them to six different treatments namely, T1: a [CO2] + a...

Drought spells and heat stress have become quite common and agricultural production would experience a lag in near future. The combined effect of heat and drought stress is expected to cause negative impact on crop growth. Hence, an experiment was framed to assess the morphological and photosynthetic characters of chilli under combined drought and...

Crop management is one of the most important factors in modern agricultural activity. Studying the balance of growth stages and supplying optimal quantities of mineral nutrients and hormones to growing plants is essential to improve yield in short duration cotton varieties. In recent years, several approaches have been tried to break this yield pla...

This study is the first and unique of open-field studies to assess the determination process of heat-induced spikelet sterility (HISS) of rice by using the same variety and the same monitoring system, MINCER (Micrometeorological Instrument for Near Canopy Environment of Rice), covering the major-rice growing regions from Sub-Saharan Africa, South,...

Combined occurrence of drought and heat stresses becomes a major constraint in the era of 21 st century. The present study was carried out in chilli K1, TNAU chilli hybrid CO1 and Ramanathapuram Gundu with six treatments of heat and drought to standardize the combined stress levels. The experiment to study the physiological basis of stress toleranc...

The study was aimed at developing submergence tolerant version of popular rice variety of Tamil Nadu namely CO 43, through marker assisted introgression of Sub1 locus from a submergence tolerant FR13A. Selfed progenies of BC2 generations were genotyped and phenotyped for submergence tolerance. Foreground selection was done using rice marker RM219 a...

Water is a key factor for the mulberry plant since, the full potential of mulberry crop production is frequently decreased by the limitations on water. The present study was carried out to assess the stomatal regulation and gas exchange parameters on four mulberry genotypes and three varieties in rain out shelter. Four months old mulberry plants we...

Rice is susceptible to heat stress at flowering, where temperatures above 33 °C during anthesis causes spikelet sterility. Heat-induced spikelet sterility at flowering is associated with reduction in grain yield. So far only N22 has been used as universal donor for heat stress. One of the major traits employed in N22 in mitigating the impact of hig...

Photosynthesis is fundamental to biomass production, but sensitive to high temperature stress. To understand the genetics of leaf photosynthesis, especially under heat, RILs of rice cv. Improved White Ponni (IWP) introgressed with QTLs controlling spikelet fertility (qHTSF 1.1 and qHTSF 4.1) were grown in temperature controlled chambers (TCCs). The...

The period from booting to flowering is the most sensitive stage to high temperature stress (HTS) in rice. The present study was aimed to improve the high temperature stress tolerance in Improved White Ponni. QTLs controlling spikelet fertility under HTS namely qHTSF 1.1 and qHTSF 4.1 was targeted for introgression from a tolerant donor Nagina 22 (...

Leaf photosynthesis, which determines the yield in rice, is greatly affected by heat and drought stresses during reproductive phenophase. The effect of short term natural high temperatures above 35 °C and drought in the range of − 50 to − 70 kPa was assessed on leaf photosynthesis (PN), stomatal conductance (gs), transpiration rate (Tr), chlorophyl...

The study was undertaken with the aim of developing a reliable and rapid screening protocol to identify crop plants with higher photosynthetic efficiencies. The vascular architecture and physiological functions of the leaves of C3 and C4 photosynthetic genetic model systems were compared. Vein densities, leaf chlorophyll index, Chlorophyll a fluore...

Submergence stress is a major problem in Tamil Nadu during the monsoons. Every year paddy production is greatly affected due to flash floods. A major QTL on chromosome 9, Sub1 has provided the opportunity to apply Marker Assisted Backcrossing (MAB) to develop submergence tolerant versions of rice cultivars that are widely grown in the region. Prese...

The time of day of flowering or the early morning flowering (EMF) trait has been demonstrated to significantly reduce heat stress damage by employing an escaping mechanism. Early flower opening is being one of the important traits that aids in the escape of rice flowers from spikelet sterility due to the high temperature stress. This strategy, whic...

In pulses, high temperature is a major limiting factor for yield decline. Tamil Nadu has a rich pulse germplasm with high genetic variability. Hence, the present study was designed to develop a technique to screen genotypes for high temperature tolerance. A rapid screening protocol was developed based on the principle of “acquired tolerance”. Adapt...

To increase the thermotolerance of improved White Ponni (IWP), two quantitative trait loci (QTLs), qHTSF1.1 and qHTSF4.1, controlling spikelet fertility under high-temperature stress, were introgressed from Nagina 22 into IWP through marker-assisted breeding. The progenies were subjected to foreground selection of target QTLs using simple sequence...

All abiotic stresses lead to evolution of oxidative stress. Relatively, research addressing the physiological basis of oxidative stress tolerance are scanty. Hence, the study was designed to induce oxidative stress, by in vivo treatment with hydrogen peroxide (H2O2 ) in rice genotypes showing contrasting behavior to flooding and salt stress. Four g...

C4 photosynthesis is the primary mode of carbon capture and drives productivity in several major food crops and bioenergy grasses. Gains in productivity associated with C4 photosynthesis include improved water and nitrogen use efficiencies. Within grasses rice and brachypodium are used as model species. Since these two crops are using C3 photosynth...

Rice is the major cereal food crop in the world. The predicted 2–4 °C increment in temperature by the end of the twenty-first century and the occurrence of drought coupled with high temperature stress situation poses a threat to rice production. There is a wealth of unexplored rice germplasm and landraces which show significant genetic variation in...

The effect of combined heat and drought stress on proline, chlorophyll stability index, membrane thermal stability and abscisic acid (ABA) contents were investigated to screen and study the physiological basis of heat and drought tolerance in three rice genotypes (ADT 43, TKM 9 and N 22). The stresses were imposed at panicle initiation (PI) and ant...

A study was conducted to find out the genetic variation for salinity tolerance in rice and finger millet genotypes. Twenty finger millet and sixteen rice genotypes were screened for their tolerance/susceptibility against salinity under hydroponics in greenhouse conditions. Screening resulted in the identification of contrasting genotypes in both th...

An experiment was conducted to study the ABA-induced changes in gas exchange parameters, in ruling varieties of soybean, green gram and black gram and to identify the crops that can show improvement in water use efficiency by maintaining higher photosynthetic rates coupled with less transpiration rates by ABA treatments. All the pulses were grown u...

The reducing and non reducing sugars in sugarcane juice and their changes in relation to maturity (9th to 13th month after planting) were analysed using HPLC in the popular sugarcane variety Co 86032. In CO 86032 sugarcane juice, no peaks of maltose, xylulose were detected while glucose, fructose and sucrose peaks were seen at 4.11, 3.76 and 4.79 r...

The response of three important pulses (Soyabean, greengram and blackgram) to exogenously applied ABA was studied in a pot culture experiment at TNAU, Coimbatore. Effects of drought stress on pulses show that photosynthesis and stomatal aperture are regulated by chemical signals. However, there are no studies to show how the stomatal aperture is co...