Background: Cercospora leaf spot (CLS) is a fungal disease of mungbean Vigna radiata (L.) Wilczek caused by Cercospora canescens and now emerged as an important biotic stress. A better understanding ...of the genetics of CLS resistance will help in formulating efficient breeding procedures in mungbean.Methods: The present investigation focused on genetics of CLS resistance through generation mean analysis (six parameter model) in two intra-specific mungbean crosses namely, Kopergaon × HUM12 and Kopergaon × ML1720. Four quantitative disease resistance components, viz., Area under disease progress curve (AUDPC), Incubation period (IP), Latent period (LP) and degree of sporulation (SP) were studied.Result: A high correlation of AUDPC with latent period (r = –0.68 to –0.79, P less than 0.0001) and SP (r = 0.72 to -0.81, P less than 0.0001) advocated that both are main contributor for CLS disease development. High heterosis along with high heritability in terms of AUDPC ( greater than 0.09) indicated the importance of genetic factor(s) in controlling CLS resistance. Generation mean analysis of both the crosses revealed duplicate epistatic interaction and involvement of two genes for CLS resistance in terms of AUDPC. This study supports oligogenic nature of inheritance, advocating AUDPC along with IP, LP and SP as important disease indicator for selection of CLS resistance in mungbean.
Lentil (Lens culinaris Medik.), an important rabi pulse crop grown in the plains of West Bengal, is vulnerable to Stemphylium blight, caused by the fungal pathogen Stemphylium botryosum. Considering ...the severity of the disease in the existing cropping system, an experiment was undertaken at the instructional farm of Uttar Banga Krishi Viswavidyalaya during Rabi 2021 with the objective to observe the correlation between the quantitative traits and the Area Under Disease Progress Curve (AUDPC) among the 50 lentil genotypes under the incidence of Stemphylium blight. The experiment was planned in Alpha Lattice design with two replications. The disease parameter AUDPC was derived from Hashemi’s disease score. A total of twenty quantitative traits viz., days to 50% flowering, plant height, primary branches/ plant, secondary branches/ plant, nodes/ plant, leaflet number, leaflet length, leaf length, tendril length, peduncle length, 100 - seed weight, seed width, seed thickness, seeds/ pod, pods/ cluster, pods/ plant, days to maturity, pod yield, harvest index and seed yield were recorded. Significant positive correlation was recorded for AUDPC with days to 50% flowering and primary branches/ plant as against significant negative correlation for AUDPC with 100- seed weight and harvest index. The study on Principal Component Analysis (PCA) revealed that the traits viz., seed yield, pod yield, leaf length, leaflet length, pods/ plant, secondary branches, seeds/ pod, days to maturity, AUDPC, nodes/ plant, days to 50% flowering, pods/ cluster, seed thickness and harvest index showed the maximum contribution towards variation (19.49%) among the PC1 variables. The PCA biplot revealed that seed yield and pod yield strongly influenced PC1. Thus, the findings of the current study might be helpful to schedule the crop improvement program as far as the response of the crop to the disease is concerned.
•Long periods of wetness and high temperatures favoured the Alternaria levels.•AUDPC and r-AUDPC showed differences in susceptibility to disease between cultivars.•LO and FB were the most resistant ...cultivars to the presence of Alternaria.•Epidemiological, aerobiological data and DSS improve the predictions of early blight.
Potato crops are susceptible to numerous field diseases causing significant losses in the quality and tuber yield. Control measures have a negative impact in soil and water resources affecting also farmers’ health and food security. Hence, a more sustainable agriculture management is a need to preserve ecosystems. Therefore, the objective of this study was to evaluate the response of nine potato cultivars (Fleur Bleue, Frisia, Fontane, Louisa, Agria, Daifla, Red Pontiac, Kennebec and Desiree) against early blight using a Decision Support Systems (DSS) in a potato-producing area from Northwest Spain. The experimental design was established using control plots and sprayed plots with fungicide according to a disease risk model adapted to the geographical region (DSS plots). Disease rating and severity were evaluated in field from the appearance of the first symptoms to final of senescence and the area under disease progress curve (AUDPC and r-AUDPC) was calculated. Aerobiological monitoring of main Alternaria species responsible potato early blight (Alternaria solani and Alternaria alternata) and the most vulnerable phenological stages were also considered. The susceptibility of the potato cultivars was analyzed based on the weather, severity of the disease and tuber yields. Specifically, temperature and leaf wetness were the meteorological variables that most influenced on the concentration of Alternaria. Conidia accounted for the previous week was the variable that most influenced in development of symptoms measured by AUDPC in natural conditions. Yields in the cultivars of DSS plots were higher than in control plots. Therefore, alternative pest management strategies, and specifically, Decision Support Systems for pest assessment are crucial for sustainable potato production. In this sense, the integration of particular information on disease resistance of commercial cultivars, phenological development of plant, or fungal particles surrounding the crop atmosphere could support these systems for better adjustment without compromising tuber yield and environment.
Fusarium wilt, whose etiological agent is the fungus Fusarium oxysporum f.sp. lycopersici (Fol), is one of the main diseases that limit tomato production. Tomato seed treatment can reduce pathogen ...infestation as well as protect seeds during seedling germination, emergence and initial development. The aim of this study was to evaluate the effect of seed treatment with natural products in order to reduce Fusarium wilt incidence in tomato seedlings. Origanum vulgare L. (Ovu) and Cinnamomum zeylanicum (Cze) essential oils (EOs) were characterized by gas chromatography (GC-FID and GC-MS). Ovu EO showed 98.46% of monoterpenes while Cze EO showed 89.27% of phenylpropanoids. The first experiment evaluated in vitro effect of EOs, carvacrol (CAR) and eugenol (EUG) at 200; 400; 600; 800 and 1,000 μg mL−1 against Fol. The lowest effective concentrations (EC100) were 323 μg mL−1 (Ovu EO) and 166 μg mL−1 (CAR). The fungicidal effect has been proven only for Ovu EO (400–1,000 μg mL−1). CAR showed fungistatic action between 200 and 1,000 μg mL−1. There was no phytotoxic effect on tomato seeds treated with Ovu EO and CAR. The second experiment was carried out with the two most active natural products that were not phytotoxic to tomato seeds. Ovu EO and CAR at 1,200 μg mL−1 reduced area under the disease-progress curve (AUDPC) by 52 and 54%, respectively. These results highlight that Ovu EO and CAR reduce the incidence of Fusarium wilt in tomato seedlings after seed treatment, without causing phytotoxic action.
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•Essential oils and their major components were active on Fusarium oxysporum f.sp. lycopersici (Fol).•Oregano essential oil (fungicidal) and carvacrol (fungistatic) were the most active against Fol.•Seed treatment with oregano essential oil and carvacrol reduced Fusarium wilt incidence.•No phytotoxic effect on tomato seeds or seedlings was observed after treatment.
Introduction Sheath blight caused by Rhizoctonia solani is one of the major diseases of rice, causing widespread crop losses. The use of semi-dwarf rice varieties in the ongoing nutrient-intensive ...rice cultivation system has further accentuated the incidence of the disease. An ideal solution to this problem would be identifying a stable sheath blight-tolerant genotype. Material and methods A multi-environment evaluation of 32 rice genotypes against sheath blight infection was conducted over six seasons across two locations (Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University (28.18° N, 38.03° E, and 75.5 masl), for four years during the wet seasons ( kharif ) from 2015 to 2018 and two seasons at the National Rice Research Institute (20°27’09” N, 85°55’57” E, 26 masl), Cuttack, Odisha, during the dry season ( rabi ) of 2019 and the kharif of 2019, including susceptible and resistant check. Percent disease index data were collected over 4 weeks (on the 7th, 14th, 21st, and 28th day after infection), along with data on other morphological and physiological traits. Result and discussion The resistant genotypes across seasons were the ones with a higher hemicellulose content (13.93-14.64) and lower nitrogen content (1.10- 1.31) compared with the susceptible check Tapaswini (G32) (hemicellulose 12.96, nitrogen 1.38), which might explain the resistant reaction. Three different stability models—additive main effect and multiplicative interaction (AMMI), genotype + genotype x environment (GGE) biplot, and multi-trait stability index (MTSI)—were then used to identify the stable resistant genotypes across six seasons. The results obtained with all three models had common genotypes highlighted as stable and having a low area under the disease progress curve (AUDPC) values. The ideal stable genotypes with low disease incidence were IC 283139 (G19), Tetep (G28), IC 260917 (G4), and IC 277274 (G10), with AUDPC values of 658.91, 607.46, 479.69, and 547.94, respectively. Weather parameters such as temperature, rainfall, sunshine hours, and relative humidity were also noted daily. Relative humidity was positively correlated with the percent disease index.
Soybean is emerging as an important legume and oil crop in Ethiopia. However, the crop has been facing serious threats from Asian Soybean Rust (ASR), causing significant damage to the crop and not ...allowing it to realize its potential. This study aimed to determine the interaction of three varieties with various fungicide treatments across two seasons and two locations to manage ASR. The experiment was laid out in a RCBD in a factorial three soybean varieties (V) and six fungicides (F) treatment combination at two locations (L) for two years (Y) with three replications. The analysis of variance across seasons revealed highly significant V × F × Y interactions for grain yield, and F × Y interactions for severity (%) and AUDPC; while efficacy was significant (P = 0.05). The V × Y interaction showed highly significant differences for AUDPC. Across locations, there were highly significant differences for V × F × L for grain yield and V × L for AUDPC. It was only AUDPC that showed significant (P = 0.05) for the V × F interaction. There were two rates (0.75 and 1 l ha−1) of the fungicide Opera Max that provided the best protection against ASR across locations, varieties, and seasons. The yield loss on the unsprayed control treatment ranged between 29 and 65%. The evidence generated from this study clearly demonstrates the importance of identifying the right variety, rates and types of fungicides for the control of ASR for higher production and productivity of soybean in Ethiopia.
•High yield losses (65%) was recorded as a result of ASR disease.•Susceptibility of varieties, and yield losses due to ASR compel fungicides use.•Varieties, fungicides, seasons and locations affected ASR management for yield.•Opera Max at the rate of 0.75 l ha−1 recommended for the management of ASR.•We recommend to study rates of Nativo and Luna Sensation for better results.
The main method of sugarcane smut (Sporisoriumscitamineum)control is the genetic resistance. This study assessed the reaction of Brazilian sugarcane genotypes to the smut. The design used was ...randomized blocks, with 41 genotypes and four replications. The experimental unit consisted of five seedlings per genotype. The genotypes were inoculated by immersing the buds in a smut spores’ suspension. For each genotype, it was obtained the disease incidence in percentage of stalk with whip and with the disease incidence data over time the area under the disease progress curve (AUDPC) were calculated for each genotype. Based in the AUDPC, three genotypes were classified as highly resistant (7.3%), eighteen as resistant (43.9%), twelve as moderately resistant (29.3%), three as moderately susceptible (7.3%) and five as susceptible (12.2%). Genotypes with higher levels of resistance to smut sugarcane can be used for integrated disease management and can be used as parents in new crosses in order to obtain progenies with higher proportion of genotypes resistant to smut.
RESUMO: O principal método de controle do carvão da cana-de-açúcar (Sporisorium scitamineum)é o controle genético. O objetivo deste estudo foi avaliar a reação de genótipos brasileiros de cana-de-açúcar ao carvão. O experimento foi conduzido em blocos casualizados, com 41 genótipos e quatro repetições. A unidade experimental foi composta por cinco mudas por genótipo. Os genótipos foram inoculados através da imersão das gemas em uma suspensão de esporos do fungo. Para cada genótipo, obteve-se a incidência da doença em percentagem de colmos com chicote de carvão e com os dados de incidência da doença ao longo do tempo foi calculada a área abaixo da curva de progresso da doença (AACPD) para cada genótipo. Baseado na AACPD, três genótipos foram classificados como altamente resistentes (7,3%), dezoito como resistentes (43,9%), doze como moderadamente resistentes (29,3%), três como moderadamente suscetíveis (7,3%) e cinco como suscetíveis (12,2%). Genótipos com os maiores níveis de resistência ao carvão da cana-de-açúcar que podem ser utilizados para o manejo integrado da doença e como genitores em novos cruzamentos para obter progênies com maior proporção de genótipos resistentes ao carvão.
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