Chickpea Abiotic Stresses: Combating Drought, Heat and Cold

Chickpea is an important legume providing dietary proteins to both humans and animals. It also ameliorates soil nitrogen through biological nitrogen fixation. Drought, heat and cold are important factors among abiotic stresses limiting production in chickpea. Identification, validation and integration of agronomic, physiological and biochemical traits into breeding programs could lead to increased rates of genetic gain and the development of better adapted cultivars to abiotic stress conditions. This chapter illustrates the effects of stresses on chickpea growth and development. It also reviews the various traits and their relationship with grain yield under stress and proposes recommendation for future breeding

Soil moisture stress effects on soybean vegetative, physiological, and reproductive growth and post-harvest seed physiology, quality, and chemical composition

With the increasing scarcity of water resources, soil moisture stress is the single most threat to global soybean production causing extensive yield losses. The objectives of this study were to investigate soil moisture stress effects on all aspects of soybean growth and development processes and to develop functional algorithms that could be used for field management decisions and in soybean crop modeling. To fulfill these objectives, six experiments were conducted; one in vitro osmotic stress study on seed germination, four studies by imposing five soil moisture treatments, 100, 80, 60, 40, and 20% of daily evapotranspiration of the control at different growth stages using sunlit plant growth chambers, and one transgenerational study on seed germination at different osmotic levels and offspring growth at three irrigation treatments (100, 66, and 33% based on field capacity) for plants grown at different soil moisture levels. Two cultivars from maturity group V, Asgrow AG5332 and Progeny P5333RY, with different growth habits were used in all these studies. Midday leaf water potential, plant height, mainstem nodes, gas-exchange traits, canopy reflectance, and several yield components including pod weight, seed yield, and seed quality were measured. Soil moisture stress decreased biomass, net photosynthesis, yield, individual seed weight, maximum seed germination, protein, fatty acids, sucrose, N, and P and increased oil, stachyose, Fe, Mg, Zn, Cu, and B contents. Overall, Asgrow AG5332 was more tolerant to drought stress than Progeny P5333RY. Soil moisture stress induced changes in seed quality that were correlated with seed germination and seedling vigor in the F1 generation. These data can be used to build a model-based decision support system capable of predicting yield under field conditions

Characterization of Physical and Biochemical Traits in Wheat and Corn Plants Using High Throughput Image Analysis

Plant phenotyping has been recognized as a rapidly growing field of research due to the labor-intensive, destructive, and time-consuming nature of traditional phenotyping methods. These phenotyping bottlenecks can be addressed by advancements in image-based phenotyping like RGB and hyperspectral imaging for the assessment of plant traits important for breeding purposes. This study aims (1) to characterize the physical and biochemical traits of wheat and corn plants using RGB and hyperspectral imaging in the greenhouse, and (2) to estimate leaf nitrogen (N), phosphorus (P), and potassium (K) content using hyperspectral imaging and an analytical spectral device (ASD spectrometer) and compare the performance from both datasets. Sixty wheat plants with 24 genotypes and 72 corn plants (a single genotype) with four different treatment combinations were manually measured and imaging was performed at different growth stages. RGB and hyperspectral images were processed to extract plant projected area (pixel count) and spectral reflectance, respectively. Partial Least Squares Regression (PLSR), Random Forest (RF), and Support Vector Regression (SVR) models were built to estimate N, P, and K contents from image-generated hyperspectral data, and from the ASD spectrometer. The results showed higher correlation for leaf area with plant pixel count with R2 of 0.75 for wheat and R2 of 0.68 for corn plants. For wheat plants, N was predicted more accurately with hyperspectral image datasets with R2 of 0.69 but P and K prediction was higher with ASD data using the PLSR model. For hyperspectral image datasets of corn plants, N prediction was higher using PLSR modeling with R2 0.66 whereas P and K prediction was higher using the RF model with R2 of 0.74 and 0.87 respectively. For corn plants using data from ASD, N, P, and K were predicted high by using the RF model with R2 of 0.67,0.41, and 0.69 respectively. RGB and hyperspectral imaging would reduce the need for manual measurement and chemical analysis of leaf tissue, and the technique can be validated in other crops with different architectures for high-throughput macronutrient estimation. The findings from this study can help integrate various disciplines of science, including plant breeding, agronomy, computer vision, mathematics, and engineering, for crop improvement. Advisor: Yufeng G

Response of plant growth and development to different light conditions in three model plant systems

Shade avoidance response to the reduced ratio of red:far-red (R:FR) light was studied in a white aspen Populus alba clone \u27Bolleana\u27 using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The response to low R:FR The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were 27% taller and 22% heavier in stem dry weight than trees grown inside the FR-blocking filter chambers. Stem taper of clear chamber trees was 16% less than the FR-blocking filter trees. Low R:FR also induced 13% greater petiole length per leaf compared to the FR-blocking filter trees.;The immutans (im) variegation mutant of Arabidopsis has green and white leaf sectors due to the action of a nuclear recessive gene. IM is a chloroplast homolog of the mitochondrial alternative oxidase. The ghost (gh) variegation mutant of tomato bears phenotypic similarities to im. We show that the im and gh phenotypes arise from mutations in orthologous genes. Structural analyses reveal that AOX, IM and GH are RNR R2 di-iron carboxylate proteins with perfectly conserved Fe-coordinating ligands that define a quinol-binding catalytic site. IM has a global impact on plant growth and development and that it is required for the differentiation of multiple plastid types. IM transcript levels do not necessarily correlate with carotenoid pool sizes, raising the possibility that IM function is not limited to carotenogenesis. Leaf anatomy is radically altered in the green and white sectors of im. The green im sectors have significantly higher than normal rates of O2 evolution and significantly elevated chlorophyl a/b ratios, typical of those found in sun leaves. We conclude that IM and GH are plastid quinol oxidases that act downstream from a quinone pool to dissipate electrons in plastids. In addition, im interrupts plastid-to-nucleus signaling pathways that control Arabidopsis leaf developmental programming

Morpho-physiological parameters associated with chlorosis resistance to iron deficiency and their effect on yield and related attributes in potato (Solanum tuberosum L.)

The aim of the study was to assess genotypical differences over different stages for morphophysiological parameters associated with iron (Fe) deficiency and their effect on yield. The factorial pot experiment was comprised of two major factors, i) soil-Fe status of natural vertisol [Fe-sufficient and Fe-deficient soils], and ii) genotypes [CP-3443, CP- 4105, CP-3486 and CP-4069] with differential iron-induced deficiency chlorosis (IDC) response. Data were recorded and associations between different traits were estimated. Under Fe-deficient soil, tolerant genotype (CP-3443) recorded significantly higher chlorophyll content, peroxidase activity in leaves, and better yield compared to susceptible genotypes which verified usefulness as IDC tolerant potato genotypes characteristics

Quantitative estimation of plant characteristics using spectral measurement: A survey of the literature

There are no author-identified significant results in this report

Effect of Nitrogen Deficiency and Fusarium Graminearum Infection on Relative Chlorophyll Content of Maize Seedlings

Nowadays the global climate change significantly affects the agricultural production due to different biotic and abiotic stresses. Phythopathogens, like fusarium, can cause serious injury which could be worsened by climatic conditions. The goal of our experiment was to examine the single and the combined effect of nitrogen (N) deprivation and Fusarium graminearum infection on the physiology of some maize genotypes. Furthermore, we would like to know the impact of the mentioned factors on the rate of nitrogen remobilization and relative chlorophyll content (SPAD value) of leaves with different ages. Controlled pot experiment was set up in a climate room, maize (Zea mays L.) genotypes were grown using hydroponic conditions. Inoculation of Fusarium graminearum conidia was performed as a biotic stress at 5-leaf (V5) stage of the seedlings and two N level were used during the experiment: optimal N and a quarter of it from the beginning. Our results suggest that N deprivation influenced the SPAD values regardless of the age of leaves and genotype. Strong interaction was found between infection and N level in case of the younger leaves. In these leaves the relative chlorophyll content was significantly decreased due to inoculation, but just at optimal N level

Effect of nitrogen deficiency and fusarium graminearum infection on relative chlorophyll content of maize seedlings

Nowadays the global climate change significantly affects the agricultural production due to different biotic and abiotic stresses. Phythopathogens, like fusarium, can cause serious injury which could be worsened by climatic conditions. The goal of our experiment was to examine the single and the combined effect of nitrogen (N) deprivation and Fusarium graminearum infection on the physiology of some maize genotypes. Furthermore, we would like to know the impact of the mentioned factors on the rate of nitrogen remobilization and relative chlorophyll content (SPAD value) of leaves with different ages. Controlled pot experiment was set up in a climate room, maize (Zea mays L.) genotypes were grown using hydroponic conditions. Inoculation of Fusarium graminearum conidia was performed as a biotic stress at 5-leaf (V5) stage of the seedlings and two N level were used during the experiment: optimal N and a quarter of it from the beginning. Our results suggest that N deprivation influenced the SPAD values regardless of the age of leaves and genotype. Strong interaction was found between infection and N level in case of the younger leaves. In these leaves the relative chlorophyll content was significantly decreased due to inoculation, but just at optimal N level

Biostimulant Effects of Seed-Applied Sedaxane Fungicide: Morphological and Physiological Changes in Maize Seedlings

Most crops are routinely protected against seed-born and soil-borne fungal pathogens through seed-applied fungicides. The recently released succinate dehydrogenase inhibitor (SDHI), sedaxane®, is a broad-spectrum fungicide, used particularly to control Rhizoctonia spp., but also has documented growth-enhancement effects on wheat. This study investigates the potential biostimulant effects of sedaxane and related physiological changes in disease-free maize seedlings (3-leaf stage) at increasing application doses (25, 75 and 150 μg a.i. seed-1) under controlled sterilized conditions. We show sedaxane to have significant auxin-like and gibberellin-like effects, which effect marked morphological and physiological changes according to an approximate saturation dose-response model. Maximum benefits were attained at the intermediate dose, which significantly increased root length (+60%), area (+45%) and forks (+51%), and reduced root diameter as compared to untreated controls. Sedaxane enhanced leaf and root glutamine synthetase (GS) activity resulting in greater protein accumulation, particularly in the above-ground compartment, while glutamate synthase (GOGAT) activity remained almost unchanged. Sedaxane also improved leaf phenylalanine ammonia-lyase (PAL) activity, which may be responsible for the increase in shoot antioxidant activity (phenolic acids), mainly represented by p-coumaric and caffeic acids. We conclude that, in addition to its protective effect, sedaxane can facilitate root establishment and intensify nitrogen and phenylpropanoid metabolism in young maize plants, and may be beneficial in overcoming biotic and abiotic stresses in early growth stages