Area Under Disease Progress Curve Research Articles

Genetic potentiality of Pumpkin genotypes against Pumpkin yellow vein mosaic virus

Pumpkin (Cucurbita moschata Duch. ex Poir.), a nutritious vegetable, is susceptible to several diseases, with Pumpkin Yellow Vein Mosaic Virus (PYVMV) causing severe impact by affecting plants at all growth stages, leading to substantial yield losses, vegetable shortages, and malnutrition in Bangladesh. This study evaluated thirty pumpkin genotypes for PYVMV resistance, genetic potential, and yield characteristics, sourced from Advanced Chemical Industries (ACI) Agribusiness and various districts in Bangladesh. For agronomic and molecular assays, thirty pumpkin genotypes along with the standard check were planted following RCBD with three replications at BAU-GPB farm. Whitefly-mediated inoculation in a net house assay determined the Area Under Disease Progress Curve (AUDPC) under controlled conditions. Tissue Blot Immunoassay (TBIA), using rabbit antiserum specific to PYVMV, showed no cross-reactivity with non-target viruses, with consistent results across TBIA, AUDPC, and molecular assays. Infected younger leaves were collected for virus-specific molecular analyses. Three sets of SSR markers were used to identify genes responsible for PYVMV resistance. PYABFP & PYABRP and PYBHFP & PYBHRP primer sets were capable of producing expected fragment.ToLCV1100F & ToLCV1650R primer sets were used for final confirmation. Genotypes PK2, PK5, and PK17 showed superior performance with higher individual fruit weights, more fruits per vine, higher overall yields, and minimal viral infection compared to the check variety (Baromashi). In contrast, PK1, PK6, PK25, and PK27 exhibited poor yield and related traits. Marker analysis revealed the absence of resistance genes in PK1, PK3, PK4, PK6, PK7, PK8, PK9, PK10, PK11, PK12, PK13, PK14, PK15, PK16, PK18, PK19, PK20, PK21, PK22, PK23, PK24, PK25, PK26, PK27, PK28, PK29, and Baromashi (control), but confirmed the presence of resistance genes in PK2, PK5, and PK17. Consequently, PK2, PK5, and PK17 were recommended as PYVMV-resistant genotypes with high yielding genetic potentiality.

Assessing Broccoli Cultivar Susceptibility to Alternaria brassicicola in Georgia

Alternaria leaf blight and head rot (causal agent: Alternaria brassicicola and other Alternaria species) in broccoli ( Brassica oleracea L. var. italica) can lead to decreased yields, reduced head quality, and postharvest losses. While cultural practices and fungicides can decrease disease severity, further work is needed to determine resistance or susceptibility in commercial cultivars. This study evaluated the susceptibility of 26 cultivars against A. brassicicola in fall 2021 and 2022 at two locations in Georgia (Tifton and Watkinsville). Commonly used cultivars in the eastern United States were selected and grown in a randomized complete block design. Approximately 20 days after transplant, plants were inoculated with a conidial suspension of A. brassicicola and monitored for disease development. Foliar disease severity, foliar area under the disease progression curve (AUDPC), head disease severity, and yield were determined for each cultivar at each location. Significant differences existed among cultivars (year × location) for foliar AUPDC and head disease severity. Foliar AUPDC ranged from 299 to 1,818 for both years and locations, and head disease severity ranged from 1 to 81% across both years and locations. In this study, cultivars ‘Eastern Crown’, ‘Emerald Jewel’, ‘Lieutenant’, and ‘Abrams’ had greater foliar and head disease severity and lower marketable yields in both locations and years. The cultivars ‘Vallejo’, ‘Emerald Pride’, ‘Burney’, ‘Belstar’, ‘Iron Man’, and ‘Marathon’ exhibited low disease severity across both locations and years and maintained greater marketable yields. Proper selection of commercially available cultivars could help growers maintain yields in areas with high A. brassicicola pressure.

Identification of Resistance to <i>Puccinia striiformisf</i>. sp. <i>tritici</i> (<i>Pst</i>) in Some Commercial and Elite Bread Wheat Lines

Stripe rust is caused by <i>Puccinia striiformisf</i>. sp. <i>tritici</i> (<i>Pst</i>) threatening wheat production in Ethiopia. The emerged virulent stripe rust races at one point of the world spread to the rest of wheat-producing countries by the wind as well as human travels and damaged popular resistant wheat cultivars thereby posing food insecurity. However, wheat cultivars succumb to new Pst race (s) soon after their release from research centers. This study aimed to determine stripe rust resistance in some Ethiopian commercial and elite bread wheat lines. In 2017, a total of 37 commercial and elite bread wheat lines were exposed to stripe rust in under the disease hot spot areas (Kulumsa and Meraro) Arsi zone Oromia regional state. In the second year (2018), 22 promising lines consisting of 16 commercial bread wheat and 6 elite’s lines were evaluated both at seedling and adult plant growth stages. The seedling test was conducted in the greenhouse at Kulumsa research center using three Pst races. In field evaluations, terminal severity (TRS), coefficient of infection (CI), area under disease progress curve (AUDPC), disease progress rate (DPR), and spike infection (SI) were considered. Of the 37 commercial and elite bread wheat lines, 19 (51.4%) exhibited lower or equal disease reaction compared to the resistant check (Enjoy) across locations and seasons. Eleven bread wheat lines showed both adult plant and seedling resistance. The 37 commercial wheat lines that showed field resistance was further exposed to three Pst races at the seedling stage and 11 exhibited seedling resistance to all races. This study has identified seedling and adult plant resistance in some commercial and elite bread wheat lines to the prevailing Pst races.

Development of infectious clones of mungbean yellow mosaic India virus (MYMIV, Begomovirus vignaradiataindiaense) infecting mungbean [Vigna radiata (L.) R. Wilczek] and evaluation of a RIL population for MYMIV resistance.

Yellow mosaic disease (YMD) is a major constraint for the low productivity of mungbean, mainly in South Asia. Addressing this issue requires a comprehensive approach, integrating field and challenge inoculation evaluations to identify effective solutions. In this study, an infectious clone of Begomovirus vignaradiataindiaense (MYMIV) was developed to obtain a pure culture of the virus and to confirm resistance in mungbean plants exhibiting resistance under natural field conditions. The infectivity and efficiency of three Agrobacterium tumefaciens strains (EHA105, LBA4404, and GV3101) were evaluated using the susceptible mungbean genotype PS16. Additionally, a recombinant inbred line (RIL) population comprising 175 lines derived from Pusa Baisakhi (MYMIV susceptible) and PMR-1 (MYMIV resistant) cross was developed and assessed for YMD response. Among the tested Agrobacterium tumefaciens strains, EHA105 exhibited the highest infectivity (84.7%), followed by LBA4404 (54.7%) and GV3101 (9.80%). Field resistance was evaluated using the coefficient of infection (CI) and area under disease progress curve (AUDPC), identifying seven RILs with consistent resistant reactions (CI≤9) and low AUDPC (≤190). Upon challenge inoculation, six RILs exhibited resistance, while RIL92 displayed a resistance response, with infection occurring in less than 10% of plants after 24 to 29 days post inoculation (dpi). Despite some plants remaining asymptomatic, MYMIV presence was confirmed through specific PCR amplification of the MYMIV coat protein (AV1) gene. Quantitative PCR revealed a very low relative viral load (0.1-5.1% relative fold change) in asymptomatic RILs and the MYMIV resistant parent (PMR1) compared to the susceptible parent (Pusa Baisakhi). These findings highlight the potential utility of the developed infectious clone and the identified MYMIV-resistant RILs in future mungbean breeding programs aimed at cultivating MYMIV-resistant varieties.

Response of Nepalese Rice Landraces to Brown Spot [Bipolaris oryzae (Breda de Haan) Shoemaker] at Rampur, Chitwan, Nepal

Brown spot disease, caused by the fungus Bipolaris oryzae, is a common foliar affliction in rice plants, impacting agricultural yields worldwide. A field experiment was conducted to identify brown spot resistant landraces at Rampur, Chitwan during June to November, 2018. A set of 54 rice genotypes comprising of 52 landraces and two checks (resistant and susceptible) were evaluated for resistance to the disease under field condition in alpha lattice design with three replicates. Area under disease progress curve (AUDPC) values varied significantly among the genotypes. Of the tested 54 genotypes, nine genotypes were found moderately resistant, 38 genotypes susceptible and seven genotypes were found highly susceptible. The maximum incidence (64.9%) of pathogen was found in seed of Hodbachhi followed by Sankharika (64.15%). The minimum average incidence of pathogen was found in check Sabitri (4.05%), which was as par with other 28 genotypes. The yield attributing characters were highly significant among the genotypes. Highest grain yield (1.55 t ha-1) was obtained from Ghusara (1.51 t ha-1) followed by Lalbachhi. Lowest grain yield was obtained from Ghuyeni Saro (0.21 t ha-1) followed by Jaguli Mansuli (0.25 t ha-1). All the yield and yield attributing characters were negatively correlated with AUDPC. Seed-borne infection after harvest was highly significant among the genotypes. The results revealed that among the screened genotypes most of the landraces of rice are susceptible to brown spot.

Study of area under disease progressive curve (AUDPC) on collar rot disease of Indian bean caused by Sclerotium rolfsii in South Gujarat

Study of area under disease progressive curve (AUDPC) on collar rot disease of Indian bean caused by Sclerotium rolfsii in South Gujarat

Greenhouse Screening of Cotton Varieties Against Fusarium Wilt Complex

Fusarium oxysporum f. sp. vasinfectum race 1 and 2 (FOV) and the Meloidogyne incognita (southern root-knot nematode, RKN) complex can cause severe losses in cotton, and management recommendations include using varieties that are resistant to RKN. The objective of this project was to test the response of different varieties to the Fusarium wilt complex with and without RKN resistance. Four greenhouse trials were conducted, where cultivars infested with RKN and FOV were evaluated on (i) leaf wilt symptoms rated every 3 to 4 days to calculate the area under disease progress curve (AUDPC) and (ii) visual ratings of root and stem necrosis at the end of each trial. RKN-resistant cultivars PHY 480 W3FE and DP 1747NR B2XF had statistically similar AUDPC, root necrosis, and stem necrosis as RKN-susceptible cultivars DP 1522 B2XF and DP 1646 B2XF in all trials. This demonstrated that RKN resistance does not correlate to FOV resistance, and RKN resistance alone is not sufficient to manage Fusarium wilt. Cultivar ST 4946GLB2, which carries both RKN and FOV resistance, statistically had the lowest AUDPC, root necrosis, and stem necrosis in all greenhouse trials.

Detection of yellow mosaic virus resistance in Soybean (Glycine max L.) genotypes for yield and related traits

Background Twenty soybean genotypes were screened for Soybean yellow mosaic virus (YMV) identification which were collected from the Genetics and plant breeding farm laboratory. Methods To evaluate genetic studies of the chosen materials, the use of a net house assay upon sap inoculation made it easier to determine the trend of the Area Under Disease Progress Curve (AUDPC) in a controlled environment. Younger leaves from these plants were gathered and used for molecular analysis. Results Six genotypes were identified with semi-resistant disease reactions. Yellow mosaic virus-resistant and susceptible soybean genotypes were distinguished using a soybean “Rsv1-h” gene-based primer pair. To discover the existence of the Rsv-1-h gene responsible for YMV resistance, a genetic diversity panel of 15 soybean genotypes was investigated with two simple sequence repeat (SSR) markers. The BARCSOYSSR_13_1115 and BARCSOYSSR_13_1173 primer sets were employed to validate the desired genes in these genotypes. Conclusion The genotypes HIHS-WIHS, MINA-HAI, Shohag, G-2120, BRAGG, and BS-3 presented the major gene Rsv1-h, which is said to be essential for yellow mosaic virus resistance and can provide better yield also than other genotypes. The six soybean genotypes with the Rsv1-h gene may be resistant to mosaic virus and could be exploited as a source of improved breeding material in the future.

Effect of Weather Parameters on Disease Severity and Progression of Fusarium Wilt in Chilli (Capsicum anuum L.)

Fusarium wilt incited by Fusarium oxysporum is an economically damaging disease of chilli (Capsicum anuum L.). Field experiments on epidemiological studies were conducted using susceptible variety (Pusa Jwala) to study the effect of weather parameters on the progression of the disease. The study revealed that transplanting chilli during the first half of July reduced the disease severity compared to earliest transplant dates. The area under disease progress curve (AUDPC) and the apparent infection rate were lowest in the crop transplanted on 15th July, 2022 while they were highest in the crop transplanted on 15th June, 2022. The correlation analysis showed a positive correlation between disease severity and bright sunshine hours, and a negative correlation with the other weather parameters. The R2 value obtained from multiple regression equations revealed that the combined effect of weather parameters could explain the prediction of a disease level of 83-86 per cent at all three transplant dates.

Application of Bio P60 and Bio T10 alone or in combination to control Fusarium wilt of Hydroponic Melon

The research aimed to determine the effect of single and combined applications of Bio P60 and Bio T10 in suppressing stem base rot and its effect on the growth and production of hydroponic melon. This research was conducted at Flos Hydroponic Organic at Bansari Village, Bansari District, Temanggung Regency from February to June 2023. Randomized Block Design was used with 6 replicates. The treatments were control (propamocarb hydrochloride), Bio P60, Bio T10, and a combination of Bio P60 and Bio T10 (1:1, v/v). Variables observed were incubation period, disease intensity, infection rate, area under disease progress curve (AUDPC), control effectiveness, plant length, number of leaves, fresh weight, leaf color, first flowering date, first fruit formation, number of fruits per plant, fruit weight per plant, and phenolic compounds qualitatively. The results showed that the combined treatment of Bio P60 and Bio T10 had the best effect indicated by delaying the incubation period, reducing disease intensity, reducing infection rates, reducing AUDPC values, increasing the value of control effectiveness, increasing plant length, number of leaves, plant fresh weight, leaf color, time of first flower appearance, time of fruiting, and fruit weight respectively of 31.25, 41.19, 13.33, 65.31, 55.61, 17.25, 5.57, 36.44, 11.47, 8.55, 9.63, and 22.92 % compared to control. The application of Bio P60, Bio T10, and the combination could increase the phenolic compounds (tannins, saponins, and glycosides) qualitatively in melon leaves.

Biopotential of Cyanobacteria, Fulvic Acid and Nano-chitosan in Controlling Leaf Rust of Wheat

Biocontrol agents, including Cyanobacteria, Spirulina platensis and Nostoc calcicole, as well as Fulvic Acid and nano-chitosan were tested to control leaf rust of wheat under field conditions during 2021/2022 and 2022/2023 growing seasons. All biocontrol agents significantly reduced all parameters for disease severity i.e. coefficient of infection (CI), the average coefficient of infection (ACI) and the area under disease progress curve (AUDPC) compared to untreated control. The best treatments were nano-chitosan which recorded efficacy of 91.17% followed by S. platensis (90.2%) in the application of two sprays for disease control. All biocontrol agents significantly increased grain yield components of wheat. Applications of two sprays were more effective than one spray. From our research work it can be concluded that S. platensis, N. calcicole, Fulvic Acid and nano-chitosan can be used for controlling leaf rust disease as a safe alternative to chemical fungicides.

Impact of Weather Parameters and Time of Sowing on Severity of Powdery Mildew in Cluster Bean

Background: Powdery mildew of cluster bean causes considerable yield loss upto 50-55%. Studies carried on cluster bean powdery mildew are very few and as such there is no information related to epidemiology of the disease. Environmental factors decide the epidemic of the disease and are being used to forecast the disease severity. Methods: Five different dates of sowing of cluster bean were evaluated in a randomized complete block design with four replications at Main Agricultural Research Station, College of Agriculture, Dharwad. Observations on the first appearance of the disease and severity were recorded at weekly intervals using disease scoring scale 0-9 and along with pod yield were considered for statistical analysis. The weather data was used to correlate with the disease severity and correlation matrix was worked out. Further, the observations were converted to % disease index to calculate rate of infection and area under disease progress curve (AUDPC) for each date of sowing. Result: Sowing of crop in first fortnight of September recorded the minimum mean disease severity of 19.10% and recorded pod yield of 4.72 t/ha with lower value of area under disease progress curve (1270.50) as against crop sown in first fortnight of November that recorded the 39.39 % of maximum mean disease severity, 3.82 t/ha pod yield and 2583.88 of area under disease progress curve. The mean maximum temperature was positively correlated (0.89) with % disease index whereas, minimum temperature (-0.87), morning relative humidity (-0.81) and evening relative humidity (-0.88) were negatively correlated with % disease index. Disease progression was started at 35 days after sowing and the maximum ‘r’ value of 0.157 was observed during the II fortnight of September followed by an ‘r’ value of 0.142 during the I fortnight of September whereas, a lower ‘r’ value of 0.009 was observed in I fortnight of September sown crop at 63-69 days after sowing.

Characterization of Quantitative Trait Loci for Leaf Rust Resistance from CI 13227 in Three Winter Wheat Populations.

Leaf rust is a widespread foliar wheat disease causing substantial yield losses worldwide. Slow rusting is "adult plant" resistance that significantly slows epidemic development and thereby reduces yield loss. Wheat accession CI 13227 was previously characterized as having slow-rusting resistance. To validate the quantitative trait loci (QTLs) and develop diagnostic markers for slow rusting resistance in CI 13227, a new population of recombinant inbred lines of CI 13227 × Everest was evaluated for latent period, final severity, area under the disease progress curve, and infection type in greenhouses and genotyped using genotyping-by-sequencing. Four QTLs were identified on chromosome arms 2BL, 2DS, 3BS, and 7BL, explaining 6.82 to 28.45% of the phenotypic variance for these traits. Seven kompetitive allele-specific polymorphism markers previously reported to be linked to the QTLs in two other CI 13227 populations were validated. In addition, the previously reported QLr.hwwg-7AL was remapped to 2BL (renamed QLr.hwwg-2BL) after adding new markers in this study. Phenotypic data showed that the recombinant inbred lines harboring two or three of the QTLs had a significantly longer latent period. QLr.hwwg-2DS on 2DS showed a major effect on all rust resistance traits and was finely mapped to a 2.7-Mb interval by two newly developed flanking markers from exome capture. Three disease-resistance genes and two transporter genes were identified as the putative candidates for QLr.hwwg-2DS. The validated QTLs can be used as slow-rusting resistance resources, and the markers developed in this study will be useful for marker-assisted selection.

Resistance of bread wheat (Triticum aestivum L.) varieties to fusarium head blight (Fusarium graminearum) in Ethiopia

AbstractFusarium head blight (FHB) is a devastating disease reduces wheat yield and quality. This study was aimed to evaluate wheat varieties' responses to spray inoculation with Fusarium graminearum mixture isolates under greenhouse conditions. The treatments were laid out in a randomized completely block design with three replications using 24 bread wheat varieties registered in Ethiopia. The varieties inoculated with mixed inoculum derived from four pathogenic isolates of F. graminearum that had been isolated from wheat kernels. Disease severity was evaluated using a 1–9 scale based on the proportion of bleached spikelets, and the area under disease progress curve (AUDPC) was determined from the disease severity data. At harvest, the kernel weight reduction was determined in comparison to the control. The evaluated traits were significantly interrelated and showed high and significant variation among (p < 0.0001) wheat varieties. Disease severity index among the varieties varied from 29% to 72%, while AUDPC varied from 326%‐ to 1010%‐days. The disease progress rate of the Kingbird variety inoculated with F. graminearum was the slowest (0.0191 units day−1), whereas Ogolcho had the fastest disease progression rate (0.0581 units day−1). Kingbird, Wane, and Limu were moderately resistant, with lower disease severity, AUDPC, and a reduction in 1000‐grain weight and grain weight per spike. Dereselgne, Dambal, and Ogolcho varieties were highly susceptible, with the greatest grain weight per spike reduction (53.2%, 41.4%, and 37.4%) and 1000‐grain weight reduction (41.5%, 42.8%, and 37.5%), respectively. The results implied that there were different levels of FHB resistance in Ethiopian bread wheat varieties. Although current greenhouse evaluation of varieties gives encouraging results, field testing is required to confirm the current findings.

Herbicide safener isoxadifen-ethyl associated with increased Goss's wilt severity in corn (Zea mays).

Goss's bacterial wilt and leaf blight (Goss's wilt), caused by the bacterium Clavibacter nebraskensis, is a corn disease that has been a top ten yield-reducing disease in North America in the past 15 years. Isoxadifen-ethyl is an herbicide safener that effectively increases cytochrome P450 activity in corn which enhances a plant's metabolism of herbicide molecules. Recent research found a potential link between isoxadifen-ethyl and increased Goss's wilt severity. The application of isoxadifen-ethyl increased (P = 0.014-0.046) area under disease progress curve (AUDPC) by 19%, 7%, and 9% at three environments, independent of accompanying herbicide or herbicide application timing. However, no significant differences in incidence of systemic wilt or corn grain yield occurred among treatments at any environment. These data provide evidence for an association between isoxadifen-ethyl safener and Goss's wilt in corn. The reason for this association is unknown, but the safener may affect plant or pathogen physiological mechanisms. While the increased disease severity did not result in decreased grain yield in these experiments, an increase in pathogen inoculum due to higher disease severity could influence Goss' wilt epidemics in future years. © 2024 Society of Chemical Industry.

A new bacterial consortia for management of Fusarium head blight in wheat

Fusarium head blight (FHB) is a significantly important disease in cereals primarily caused by Fusarium species. FHB control is largely executed through chemical strategies, which are costlier to sustainable wheat production, resulting in leaning towards sustainable sources such as resistance breeding and biological control methods for FHB. The present investigation was aimed at evaluating newly identified bacterial consortium (BCM) as biocontrol agents for FHB and understanding the morpho-physiological traits associated with the disease resistance of spring wheat. Preliminary evaluation through antagonistic plate assay and in vivo assessment indicated that BCM effectively inhibited Fusarium growth in spring wheat, reducing area under disease progress curve (AUDPC) and deoxynivalenol (DON), potentially causing type II and V resistance, and improving single spike yield (SSPY). Endurance to FHB infection with the application of BCM is associated with better sustenance of spike photosynthetic performance by improving the light energy harvesting and its utilization. Correlation and path-coefficient analysis indicated that maximum quantum yield (QY_max) is directly influencing the improvement of SSPY and reduction of grain DON accumulation, which is corroborated by principal component analysis. The chlorophyll fluorescence traits identified in the present investigation might be applied as a phenotyping tool for the large-scale identification of wheat sensitivity to FHB.

Reaction of Selected Citrus Cultivars to Pseudocercospora Leaf and Fruit Spot Disease Under Natural Infection in Northern Uganda

Citrus is an important crop among many resource constrained subsistence farmers living in rural areas of Uganda. Citrus production is affected mainly by drought, declining soil fertility, pests and diseases. Among diseases, citrus leaf and fruit spot disease caused by fungus Pseudocercospora angolensis is currently one of the major constraints to the production of citrus in Uganda where millions of people rely on the crop for nutritional security and household income. The disease can lead to 50-100% fruit yield loss depending on environmental conditions, disease management and weather conditions. In order to identify resistance to P. angolensis, a study was conducted to identify variability for citrus leaf and fruit spot resistance from adapted commercial cultivars as an initial step in developing integrated disease management strategy. Six cultivars were assessed. The screening was under natural infection conditions in disease hot spots in northern Uganda in 2014a and 2014b seasons. The results showed significance difference (p < 0.01) for Area Under Disease Progressive Curve (AUDPC) for number of leaves with P. angolesnis symptoms and number of lesions. Subsequently, the study identified Kuno as resistant and Tangelo as less susceptible to Pseudocercospora leaf and fruit spot infection, and they could be recommended for citrus leaf and fruit spot disease control.

Marker trait association analysis to unravel genomic regions associated with Stemphylium disease reaction in lentil

This study investigates the response of lentil genotypes to Stemphylium blight disease over two cropping years, 2021 and 2022. In addition, this research aims to assess the marker-trait association between Stemphylium disease progress and the selected SSRs. Visual symptoms were assessed using Hashemi's disease scoring system, leading to the calculation of disease parameters such as Percent Disease Index (PDI) and Area Under Disease Progress Curve (AUDPC). The results revealed variations in disease progress among genotypes, with some exhibiting low disease indices, particularly genotype IC241072. Genetic diversity analysis using SSR markers identified 30 alleles and grouped genotypes into four clusters. Principal Coordinate Analysis (PCoA) confirmed the genetic distances among genotypes. Marker-trait association analysis linked the microsatellite locus LCSSR04_130362_118bp to Stemphylium blight resistance, supported by the identification of a TCP family transcription factor in close proximity. The validation of the association indicated a significant difference between resistant and susceptible alleles. This comprehensive approach combining field screening, genetic diversity analysis, and marker-trait associations provides valuable insights into the genetic basis of Stemphylium blight resistance in lentil genotypes, offering potential candidates for future breeding programs.

Early boosting of genetically improved Falcataria moluccana with mycorrhiza for better growth and disease tolerance

Falcataria moluccana is a widespread species that grows rapidly in Indonesia and produces timber used for carpentry. Nonetheless, this species is especially susceptible to gall rust disease. To find plants that can handle rust, a mix of breeding with progeny experiments and forest management methods, like arbuscular mycorrhiza (AM), were used. The point of this study is to find out if adding AM changes how F. moluccana seedlings grow and how they react to gall rust disease, both those that have been improved and those that have not. We will also look at the response by calculating the area under disease progress curves (AUDPC) value for rust disease to grow in F. moluccana seedlings. The experimental design comprised four different treatments, including varying quantities of mycorrhizae, as well as four different seed sources. For the mycorrhizal inoculation experiments, there was a control group and three treatment groups. The treatment groups got 5, 10, and 15 g of mycorrhiza per polybag, respectively. The seeds used in this study were sourced from two unimproved families, namely Java and Solomon, as well as two genetically improved families, F63 and F77. This study revealed that mycorrhizal application affects the growth of F. moluccana seedlings and significantly reduces both disease incidence and severity. The application of mycorrhiza reduces the disease incidence and severity; the AUPDC value of seedlings with mycorrhiza added is four times lower than that of seedlings without mycorrhiza. The disease severity was highest for the unimproved Solomon seedlings, despite the fact that the source of seeds had little impact on the disease incidence. Meanwhile, the genetically improved seedlings demonstrated lower disease incidence and severity rates than seedlings without improvement, with an AUPDC value nearly half that of the unimproved seedling. In terms of diameter and height, F. mollucana seedlings derived from various seed sources were remarkably diverse, and seedlings with improvements grew much better than seedlings without improvements. This study shows how arbuscular mycorrhiza affects how well improved and unimproved F. moluccana seedlings deal with gall rust disease.

Identification of resistant sources against bakanae disease in short grained aromatic rice (Oryza sativa)

An experiment was conducted during rainy (kharif) seasons of 2019 and 2020 at the research farm of ICAR Indian Agricultural Research Institute, New Delhi to screen 90 genotypes of scented short grained rice (Oryza sativa L.) for Fusarium fujikuroi resistance. Genotypes Kankjeer A, Lectimanchi-A, Sumati, Pankhali-203, GR-102, NWGR- 3042, Geetanjali, R 1432-261-105-2-1-2, Khaskani, C-4-63-G, Calrose 76, JJ 92, Koliha, Hari Shankar, Kusuma, IR 74717-3-3-1-3, IR 74725-115-3-3-3, IR 74728-134-1-1-3, Hansraj, Anterved and GAR-1 were identified as moderately resistant with the disease rating of 3 in both the years of evaluation. Further, a set of genotypes with different disease response was evaluated for different parameters including root length, shoot length, number of fibres/threads in roots, days of symptom appearance and area under disease progress curve (AUDPC). Disease severity was observed to be significantly correlated (r = 1.0) with AUDPC and days required for the symptom appearance (r = 0.95). Results indicated that apart from the disease severity, AUDPC could also be considered as a one of the component for the bakanae disease resistance. The resistant sources identified in the present study can be utilized in rice breeding programme against bakanae disease.