When disease ratings are obtained over time, area under the disease progress metrics such as area under the disease progress curve (AUDPC) and area under the disease progress stairs (AUDPS), which ...allow integration of these measures into a single value, have found use for both survey or replicated experiment data. IdeTo, an Excel-based calculator, computes AUDPC, AUDPS, and their standardized and relative values for up to 200 individuals evaluated at 200 timepoints. In addition to the areas, descriptive statistics are provided for the group of individuals (e.g., accessions and replicates), and both Pearson and Spearman correlation coefficients between the areas and other traits of interest. Graphs are provided to visualize the progression of disease scores over time, distribution of AUDPC and AUDPS values in the dataset, and their linear correlation with the traits of interest.
Formula: see text The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2021.
•1.0% Chitosan with 600 nm droplets reduced disease severity.•1.0% Chitosan with 600 nm droplets inhibited production of cellulolytic enzymes.•1.0% Chitosan with 600 nm droplets inhibited production ...of pectinolytic enzymes.
In vitro and in vivo antifungal potential of submicron chitosan dispersions (SCD) was studied in order to investigate the effect of SCD on cell wall degrading enzymes of Colletotrichum gloeosporioides and to control anthracnose of dragon fruit under field conditions. Four concentrations of chitosan (0.5, 1.0, 1.5 and 2.0%) were used to prepare submicron dispersions with droplet sizes of 200, 400, 600, 800 and 1000 nm. The highest inhibition in cellulolytic and pectinolytic enzymes was observed with 600 nm droplet size of 1.0% chitosan concentration. In case of in vivo studies,the area under disease progress curve (AUDPC) showed a reduction of approximately 66% of disease incidence (DI). The lower level of production of cell wall degrading enzymes in response to SCD resulted in less disease on dragon fruit plants and sustained in increasing the effective resistance against the irresistible disease of anthracnose.
Background:
Maize lethal necrosis (MLN) disease continues to reduce the productivity of maize drastically threatening food security in the affected regions. It continues to cause yield loss of 30–100 ...percent in farmers’ fields, depending on the time of infestation which is valued at $198 million in Kenya. This has not only threatened regional trade, but also seed industry. It has been reported in the major maize belts of Uasin Gishu, Trans-Nzoia, Bomet, Narok and Nandi Counties. MLN is caused by the synergistic interaction between
Sugarcane Mosaic Virus
(SCMV) and
Maize Chlorotic Mottle Virus
(MCMV). The disease has then spread to other Eastern and Central African countries with devastating food security and economic consequences.
Objectives:
This study highlights result after screening selected maize inbred lines for resistance to MLN, SCMV and MCMV in identifying promising lines for integration into the breeding program for MLN resistance.
Methods:
Sixty-five (65) maize genotypes were artificially inoculated using virus strains collected from Bomet County in Kenya at 3-4 leaf stage. Data on disease severity and incidence, AUDPC and flowering were recorded.
Results:
From the result, the inbred lines had significant differences for SCMV, MCMV and MLN reactions. Based on Area Under Disease Progress Curve (AUDPC) score and ELISA analysis, genotypes MLN001 and MLN006 have the lowest score of 270, whereas OH28 had a maximum at 1259 under MCMV. Genotypes MLN042 and MLN041 were identified as the most promising sources of resistant against SCMV. However, no genotype was identified to have acceptable levels of tolerance to MLN, but MLN001 and MLN013 were identified as the best performers under MLN. This study also validated the presence of MLN tolerance in MLN013 (CKDHL120312) and MLN001 (CKDHL120918) as earlier reported by CIMMYT. These tolerant genotypes are now serving as donors in the introgression of the tolerance into the Kenyan adapted maize backgrounds and development of improved MLN tolerant varieties. This will go a long way in restoring and ensuring sustainable maize productivity in improving the livelihoods of the smallholder farmers who form 75% of the major maize producers in Kenya.
Conclusion:
The identified inbred lines would be recommended for use in varietal development, MLN management and to enhance maize productivity, in the MLN endemic regions and further research in understanding the mode of gene action for MLN tolerance.
Interactions of
Fusarium
species with different wheat varieties differ in their temporal dynamics and symptom appearance. Reliable and objective approaches for monitoring processes during infection ...are demanded for plant phenotyping and disease rating. This study presents an automated method to phenotype wheat varieties to
Fusarium
head blight (FHB) using hyperspectral sensors. In time-series experiments, the optical properties of spikes infected with
F. graminearum
or
F. culmorum
were recorded. Two hyperspectral cameras, in visible and near-infrared (VIS-NIR, 400–1000 nm) and shortwave-infrared (SWIR, 1000–2500 nm) captured the most relevant bands for pigments, cell structure, water and further compounds. Correlations between disease severity (DS), spike weight, spectral bands and vegetation indices were investigated. Following, the detectability of infections was assessed by Support Vector Machine (SVM) classifier. A variety ranking based on AUDPC was performed and compared to a fully-automated approach using Non-metric Multi-Dimensional Scaling (NMDS). High correlation was found between the spectral signature and DS in 430–525 nm, 560–710 nm and 1115–2500 nm. All indices from the VIS-NIR showed high correlation with DS and, for the first time, this was also confirmed for three indices from the SWIR: NDNI, CAI and MSI. Using SVM, differentiation between healthy and infected spikes was possible (acc. > 0.76). Furthermore, the possibility to differentiate between
F. graminearum
and
F. culmorum
infected spikes has been verified. The NMDS approach was able to reproduce accurately the variety ranking and outlines the potential of hyperspectral imaging to phenotype the variety susceptibility for improved breeding processes.
Background: Leaf blight caused by Exserohilum turcicum (E. turcicum) is commonly or generally found on sorghum grown in the sub-tropics and tropical lowlands during summer. The pathogen is easily ...wind disseminated and apparently most consistent in their occurrence and severity across the diverse sorghum growing environments. The sweet sorghum variety SSV 74 was released by University of Agricultural Sciences, Dharwad for kharif season mainly for fodder purpose. This variety is also good for ethanol production and jaggery making. However, for the last several years this variety was showing its susceptibility to the leaf blight caused by E. turcicum and causes heavy losses both in fodder and its quality. Even though there are reports of the presence of leaf blight caused by E. turcicum on the grain sorghum, no precise information is available on the presence of the leaf blight on sweet sorghum in India as well as in the world and no information is available about the magnitude of losses caused by this disease. Hence, the experiment was conducted to assess the losses caused by the E. turcicum.
Methods: An experiment on loss assessment in sweet sorghum due to leaf blight caused by E. turcicum was carried out at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, during kharif 2017 using randomized complete block design (RCBD) with three replications and seven treatments. Six treatments were imposed with hexaconazole at 0.1% besides a treatment with unsprayed control.
Result: Lowest per cent disease index (PDI) (24.76%) as well as area under disease progressive curve (789.61) was observed in treatment involving six sprays of hexaconazole at 0.1% followed by five sprays, (PDI: 27.51%, AUDPC: 815.32) and four sprays T4 (PDI: 32.57%, AUDPC: 908.80). Highest fodder yield (46.47 t/ha), brix value (12.47%), crude fibre content (28.22%), leaf ash content (23.08%) and crude protein content (5.29%) was observed in treatment with six sprays of hexaconazole at 0.1%. With respect to the per cent increase over control, 17.47-37.20 per cent increase in fodder yield, 7.4-21.17 per cent in brix value, 11.64-9.66 per cent in crude fibre content, 12.74-62.91 per cent in leaf ash content and 4.36-13.00 per cent in crude protein content was observed at one spray to six sprays with hexaconazole at 0.1 per cent, respectively.
•This study was done with an objective to pool together in wheat, the three most important traits (spot blotch resistance, high yield and earliness) for warm humid Eastern Gangetic plains (EGP) of ...South Asia.•A Recombinant Inbred Line (RIL) population was developed using appropriate parents and was tested in seven environments.•Six lines were significantly superior to best check for spot blotch resistance while two for grain yield, four for earliness and two for 1000-grain weight.•One line was found significantly superior for all four traits compared to the best check.•The study demonstrated that through appropriate crossing and evaluation, it is possible to pool together spot blotch resistance, high yield and early maturity.
This study was done with an objective to attempt to pool together in wheat, the three most important traits (spot blotch resistance, high yield and earliness) for warm humid Eastern Gangetic plains (EGP) of South Asia. A Recombinant Inbred Line (RIL) population, developed from two contrasting parents (YS#58×YS#24) for spot blotch resistance, was tested in seven environments falling under three locations of EGP. Most of the components of variation for three traits were highly significant for each environment as well as in pooled analysis. In general, phenotypic correlation for Area Under Disease Progress Curve (AUDPC) among centers was high and positive. Out of 214 genotypes (211 RILs along with their parents YS#24, YS#58 and Sonalika, check for spot blotch susceptibility and earliness) tested, 15 RILs showed better resistance than the resistant parent. Measured over seven environments, six lines were significantly superior to best check for spot blotch resistance while two for grain yield, four for earliness and two for 1000-grain weight. However, only one line (#94) was found significantly superior for all four traits compared to the best check. Genotype×Environment (G×E) interaction was significant but Genotype×Year (G×Y) was non-significant which indicated the importance of locations for spot blotch. To support this fact, lines superior in one location did not perform well in the other. For resistance, line #174 performed most consistently over 7 environments. Although there was negative correlation between AUDPC and days to heading, low AUDPC was observed in two early maturing RILs (#94 and #1). The study demonstrated that through appropriate crossing and evaluation, it is possible to pool together spot blotch resistance in to high yield back ground of wheat with early maturity.
The study aimed to assess the impact of different combinations of cultivar mixtures on finger millet blast epidemics without affecting yield. The research employed Disease Progress Curves (DPCs) such ...as AUDPC, rAUDPC, and sAUDPC to evaluate leaf, neck and finger blast epidemics' severity at various time intervals. Treatments involved mixtures of pre-released cultures and commercial varieties, combined with resistant cultivars in ratios of 1:1 and 2:1 to combat blast disease. These mixtures were compared with monoculture performances (resistant and susceptible checks) and fungicide treatments. The mixture of pre-released cultures (TNEc 1285 + TNEc 1294 + TNEc 1310) combined with the resistant cultivar GE4449 at a 1:1 ratio demonstrated the most significant impact in reducing the Area Under Disease Progressive Curve (AUDPC) values for all three blast types while maintaining consistent yield. This treatment exhibited results comparable to fungicide (Tricyclazole 75% WP) sprays across trials conducted from September to December in both 2020 and 2021. Economically, the cost-benefit ratio favoured the culture composite despite its delayed onset and slower progression during disease epidemics under field conditions. The mixture of cultures demonstrated sustainable yield without requiring significant additional input costs or frequent fungicidal application in both trial periods. This suggests a promising and cost-effective approach to managing finger millet blast epidemics while maintaining yield stability in agricultural practices.
Stem rust (Puccinia graminis f. sp. tritici) is an important fungal disease of wheat (Triticum aestivum) due to its ability to cause severe yield losses on susceptible cultivars grown under conducive ...conditions. The objective of this study was to evaluate 81 Kenyan wheat cultivars for yield, agronomic traits and resistance to rust. A 3-season field experiment was conducted in a 9 × 9 partially balanced lattice design at KALRO, Njoro (0˚ 20'S and 35˚ 56'E) under stem rust (Sr) and yellow rust (Yr) pressure. The results from this study showed that effects due to season, cultivar and cultivar × season interaction were significant (p<=0.001) for number of kernels spike-1, Area Under Disease Progress Curve for stem rust (AUDPC_SR), Area Under Disease Progress Curve for yellow rust (AUDPC_YR), yield, 1000-kernel weight (TKW), biomass and days to heading. Principal component analysis showed AUDPC was the most effective disease parameter for determining rust resistance and biplot analysis identified cultivars K. Fahari, K. Kingbird, K. Songbird and K. Pelican with desirable traits for yield, TKW, biomass and kernels spike -1. Stem rust contributed to the highest in reduction of yield and TKW accounting for 12.87% and 21.95% variation, respectively while Yr contributed the most to biomass reduction accounting for 25.65% variation. From this study, cultivars Bounty, Lenana, and K. Leopard which produced high yield, low AUDPC_SR and AUDPC_YR values ranging from 3.5- 32.2 and 15.6-80.4, respectively can be used as valuable genetic stocks for improvement of rust resistance in wheat cultivars in Kenya.
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