scholarly journals Canopy temperature depression and normalized difference vegetation index as indicators of drought resistance and nitrogen recommendation in hybrid maize genotypes

2020 ◽  
Vol 7 (3) ◽  
pp. 69-75
Author(s):  
Bipin Neupane ◽  
Ankur Poudel ◽  
Pradeep Wagle
Keyword(s):  
Drought Resistance ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Canopy Temperature ◽  
Maize Genotypes ◽  
Canopy Temperature Depression ◽  
Hybrid Maize ◽  
Temperature Depression

scholarly journals Phenotyping Peanut Genotypes for Drought Tolerance

2016 ◽  
Vol 43 (1) ◽  
pp. 36-48 ◽  
Author(s):  
J.M. Luis ◽  
P. Ozias-Akins ◽  
C.C. Holbrook ◽  
R.C. Kemerait ◽  
J.L. Snider ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Canopy Temperature ◽  
Cost Effective ◽  
Aflatoxin Contamination ◽  
Drought Tolerant ◽  
Canopy Temperature Depression ◽  
Combined Use ◽  
Drought And Heat Stress

ABSTRACT Drought and heat stress can result in aflatoxin contamination of peanuts especially when this occurs during the last three to six wk of the growing season. Identifying drought-tolerant genotypes may aid in development of peanuts that are less susceptible to aflatoxin contamination. Research was conducted to phenotype seven peanut genotypes based on their response to drought stress. Six peanut genotypes that have exhibited lower aflatoxin and/or drought tolerance in previous researches (Tifguard, Tifrunner, Florida-07, PI 158839, NC 3033, C76-16) were compared to an aflatoxin-susceptible genotype, A72. The phenotyping methods included visual ratings, chlorophyll fluorescence (PIABS, ϕEO, and Fv/Fm), SPAD chlorophyll meter reading (SCMR), normalized difference vegetation index (NDVI), canopy temperature (CT), canopy temperature depression (CTD), and pod yield. Based on these traits, Tifguard and Tifrunner exhibited greater drought tolerance mechanisms than the other genotypes and may be good candidates to be incorporated in future drought tolerance studies. After the aflatoxin content of the different genotypes was measured, aflatoxin contamination showed high correlations with visual ratings (0.85), CTD (0.81), NDVI (0.79), and CT (0.73), and moderate correlations with Fv/Fm (0.62) and SCMR (0.57) (P ≥ 0.05). These easily measurable, rapid and cost-effective phenotyping methods may be used as alternative to more tedious and costly methods of identifying genotypes that are less susceptible to aflatoxin contamination. Using a combination of these methods is beneficial but not always practical. The combined use of visual ratings, CTD and NDVI is advised for initial evaluation of drought tolerance in peanut genotypes.

scholarly journals Suitability of Canopy Temperature Depression, Specific Leaf Area, and SPAD Chlorophyll Reading for Genotypic Comparison of Peanut Grown in a Sub-humid Environment

2014 ◽  
Vol 41 (2) ◽  
pp. 100-110 ◽  
Author(s):  
D. Singh ◽  
M. Balota ◽  
T. G. Isleib ◽  
E. Collakova ◽  
G. E. Welbaum
Keyword(s):  
Leaf Area ◽  
Water Deficit ◽  
Specific Leaf Area ◽  
Canopy Temperature ◽  
Physiological Characteristics ◽  
Growth Stages ◽  
Pod Yield ◽  
Humid Environment ◽  
Canopy Temperature Depression ◽  
Temperature Depression

ABSTRACT Peanut (Arachis hypogaea L.) is mostly grown under rainfed production with water deficit being the major limiting factor. Several physiological characteristics have been proposed as surrogates for yield and genotypic selection under water deficit in arid climates, but their suitability for selection under sub-humid rainfed production where water deficit can also occur is not clear. Canopy temperature depression (CTD), specific leaf area (SLA), and SPAD chlorophyll reading of eight virginia-type peanut genotypes were evaluated at three growth stages in field trials involving rainfed and irrigated plants in sub-humid environments in northeastern Virginia-Carolina (VC) region in 2011 and 2012. Significant (p≤0.05) variation in pod yield and all physiological characteristics was observed in response to water regime in both years. Rainfed plants had warmer (CTD 2.2 vs. 3.1 °C) and greener canopies in 2011 but cooler (CTD 3.9 vs. 2.2 °C) and less green canopies in 2012 than the irrigated plants. Compared to irrigated plants, rainfed plants had slightly increased SLA in 2011 (135 vs. 131 cm2 g−1), but decreased SLA in 2012 (133 vs. 144 cm2 g−1). Differences (p≤0.05) among genotypes were observed for pod yield, SLA, and SPAD chlorophyll reading, but not for CTD. Among the physiological characteristics, only SPAD chlorophyll readings were significantly correlated to pod yield in all water regimes and growth stages in 2012, but not in 2011. Based on these results, CTD, SLA, and SPAD chlorophyll reading appear to be unsuited for genotypic selection for yield and water-deficit tolerance for peanut grown in sub-humid environment of the Virginia-Carolina region in part due to unpredictable rainfall amount and distribution. For reproducible field evaluations, additional methods will have to be used such as use of rain exclusion shelters.

scholarly journals Physiological Efficiency of Sugarcane Clones under Water-Limited Conditions

2020 ◽  
Vol 63 (1) ◽  
pp. 133-140
Author(s):  
Raja Arun kumar ◽  
Srinivasavedantham Vasantha ◽  
Arjun S. Tayade ◽  
Sheriff Anusha ◽  
Ponmani Geetha ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Irrigation Water ◽  
Canopy Temperature ◽  
Water Security ◽  
Physiological Traits ◽  
Cane Yield ◽  
Leaf Rolling ◽  
Sugarcane Production ◽  
Canopy Temperature Depression ◽  
Temperature Depression

Highlights`Significant reductions in canopy temperature depression (CTD), chlorophyll fluorescence (Fv/Fm), SPAD index, and leaf rolling index were observed under limited irrigation during the grand growth stage of sugarcane.This study highlights the significance of CTD and Fv/Fm as useful physiological tools for selecting sugarcane clones suitable for production under water-limited conditions.Clones Co 10026, Co 13006, Co 85019, Co 62175, Co 86010, and Co 1148 performed better under limited irrigation, and these clones can reduce the amount of irrigation water required for sugarcane production, ensuring water security.Abstract. Sugarcane is one the most important commercial crops in India and globally. The annual water requirement for sugarcane ranges from about 1000 to 2900 mm, and this variation mainly depends on the agro-ecological conditions, cultivation practices, and crop cycle. In a changing climate, the delay or failure of monsoons will have a direct effect on the water available for irrigation in India. Given these constraints, sustaining sugarcane production is challenging. The ICAR-Sugarcane Breeding Institute (ICAR-SBI) in Coimbatore, India, has developed sugarcane genotypes that are resilient to drought stress. To study the role of physiological traits in identifying sugarcane varieties suitable for water-limited conditions, an experiment was conducted at ICAR-SBI with sugarcane clones in field conditions using irrigation at 100% cumulative pan evaporation (I0) and with 50% reductions in the volume and frequency of irrigation (I2). Physiological traits, including canopy temperature depression (CTD), chlorophyll fluorescence (Fv/Fm), soil plant analysis development (SPAD) index, leaf rolling index (LRI), and cane yield, were recorded for sugarcane clones grown under I0 and I2. Significant reductions of 85.9%, 15.4%, 4.9%, 44.9%, and 56.0%, respectively, in CTD, Fv/Fm, SPAD index, LRI, and cane yield were found for water-limited conditions (I2) compared to I0. Fv/Fm showed a decreasing trend in I2 compared to I0 and also showed a significant positive correlation (r = 0.43) with cane yield. CTD varied significantly between the two treatments and also showed a significant positive correlation with cane yield (r = 0.45). Both Fv/Fm and CTD are adaptive traits for water-limited conditions and are useful for screening sugarcane clones suitable for water-limited conditions. Clones Co 10026, Co 13006, Co 85019, Co 62175, and Co 86010 had superior cane yields under water-limited conditions (I2) and better physiological traits. Water deficit is one of the most critical abiotic stresses that affect sugarcane productivity. By growing clones that are water use efficient (Co 10026, Co 13006, Co 85019, Co 62175, and Co 86010), the irrigation water requirement can be reduced for sugarcane production in India. In addition, new sugarcane clones can be developed for water-limited conditions by using the identified clones in breeding programs for water use efficiency, and water security can be achieved for sugarcane grown tropical and sub-tropical areas of India. Keywords: Canopy temperature, Chlorophyll fluorescence, Global water security, Irrigation, Water productivity

scholarly journals Genome-Wide Detection of SNP Markers Associated with Four Physiological Traits in Groundnut (Arachis hypogaea L.) Mini Core Collection

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 192 ◽  
Author(s):  
Abdulwahab S. Shaibu ◽  
Clay Sneller ◽  
Babu N. Motagi ◽  
Jackline Chepkoech ◽  
Mercy Chepngetich ◽  
...  
Keyword(s):  
Core Collection ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Canopy Temperature ◽  
Snp Markers ◽  
Physiological Traits ◽  
Area Index ◽  
Trait Association ◽  
Mini Core Collection ◽  
Genome Wide

In order to integrate genomics in breeding and development of drought-tolerant groundnut genotypes, identification of genomic regions/genetic markers for drought surrogate traits is essential. We used 3249 diversity array technology sequencing (DArTSeq) markers for a genetic analysis of 125 ICRISAT groundnut mini core collection evaluated in 2015 and 2017 for genome-wide marker-trait association for some physiological traits and to determine the magnitude of linkage disequilibrium (LD). Marker-trait association (MTA) analysis, probability values, and percent variation modelled by the markers were calculated using the GAPIT package via the KDCompute interface. The LD analysis showed that about 36% of loci pairs were in significant LD (p < 0.05 and r2 > 0.2) and 3.14% of the pairs were in complete LD. The MTAs studies revealed 20 significant MTAs (p < 0.001) with 11 markers. Four MTAs were identified for leaf area index, 13 for canopy temperature, one for chlorophyll content and two for normalized difference vegetation index. The markers explained 20.8% to 6.6% of the phenotypic variation observed. Most of the MTAs identified on the A subgenome were also identified on the respective homeologous chromosome on the B subgenome. This could be due to a common ancestor of the A and B genome which explains the linkage detected between markers lying on different chromosomes. The markers identified in this study can serve as useful genomic resources to initiate marker-assisted selection and trait introgression of groundnut for drought tolerance after further validation.

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