Leaf Rust Disease Research Articles

Occurrence of leaf rust disease in Oxalis triangularis caused by Puccinia oxalidis in Valdivia, Chile.

False shamrock (Oxalis triangularis), native to South America, is an ornamental and popular plant bulb, commercialized for their attractive shape and color (purple triangular leaves) (Taha et al., 2013). In Chile, a rust was detected in O. triangularis plants growing from April to June in several gardens (n=10) in the city of Valdivia, estimating a disease incidence between 80 and 100%. The symptoms appeared as diffuse chlorotic spots from the upperside of leaves, where infected tissues eventually become completely necrotic, and yellow rust pustules were observed on the underside of leaves. Severe symptoms on infected leaves were consistently observed, showing necrosis on entire leaves. Symptomatic plants (n=50) were collected, and three representative isolates from different localities (OX1, OX2, and OX3) were used for morphological and genetic identification. Uredinia (n=20) were hypophyllous, erumpent, yellow, and irregularly distributed, with sizes from 340 to 850 μm in diameter. Urediniospores (n=150) were yellow, subglobose to globose, equinulate, with measures of 14.2 - 17.7 x 14.7 - 17.2 µm. Teliospores were absent. Based on morphological characters, this rust was identified as a Puccinia sp. These morphological characteristics coincided with those indicated by Šafránková (2014), Abbasi et al. (2018), and Khouader et al. (2018). To classify this rust genetically, sequences analyses were performed using the ITS region of the rDNA (ITS4/ITS5) (White et al., 1990). The DNA was extracted using a commercial kit. The results indicated 99% similarity with two reference sequences of P. oxalidis (MH325473 and MH325474) available at GenBank (NCBI http://www.ncbi.nlm.nih.gov/BLAST/). The sequences obtained were deposited in GenBank (ON259085 to ON259087). Based on the maximum parsimony phylogenetic tree, the sequences of Chilean isolates were clustered with those of P. oxalidis references. Pathogenicity tests were conducted using three isolates (OX1 to OX3). Surface disinfection of leaves of O. triangularis (n=36 plants), were performed by spraying 1% NaOCl solution for 1 min. Subsequently, 2 mL of urediniospores suspensions of each isolate (OX1 to OX3) at a concentration of 106 urediniospores/mL, were sprayed with an atomizer on the underside of the leaves of all plants. Urediniospores were obtained following the methodology proposed by Ferrada et al. (2020). Control leaves were disinfested and inoculated with sterile distilled water. Plants of O. triangularis of 90-day-old were incubated in a humid chamber (24°C, 80% HR), with a photoperiod of 12 light /12 dark. At 11 days post-inoculation, all leaves inoculated developed chlorosis spots and pulverulent pustules (averaged 10.9 to 25.4 pustules per leaf), and then at 26 days post-inoculation, affected leaves showed necrotic tissues. The identity of these isolates was confirmed morphologically. The symptoms in the control leaves were negative. To our knowledge, this is the first report of multiple occurrences of the leaf rust disease on gardens of false shamrock caused by P. oxalidis in Valdivia, south of Chile. Previously, P. oxalidis has been reported to cause leaf rust disease in O. triangularis in the Czech Republic (Šafránková, 2014) and O. debilis in Korea (Lee et al., 2018). The leaf rust disease could represent a threat to the ornamental gardens of O. triangularis in Valdivia. Currently, epidemiological studies of leaf rust disease are necessary to develop management strategies in gardens of O. triangularis.

Mining the Australian Grains Gene Bank for Rust Resistance in Barley.

Global barley production is threatened by plant pathogens, especially the rusts. In this study we used a targeted genotype-by-sequencing (GBS) assisted GWAS approach to identify rust resistance alleles in a collection of 287 genetically distinct diverse barley landraces and historical cultivars available in the Australian Grains Genebank (AGG) and originally sourced from Eastern Europe. The accessions were challenged with seven US-derived cereal rust pathogen races including Puccinia hordei (Ph-leaf rust) race 17VA12C, P. coronata var. hordei (Pch-crown rust) race 91NE9305 and five pathogenically diverse races of P. striiformis f. sp. hordei (Psh-stripe rust) (PSH-33, PSH-48, PSH-54, PSH-72 and PSH-100) and phenotyped quantitatively at the seedling stage. Novel resistance factors were identified on chromosomes 1H, 2H, 4H and 5H in response to Pch, whereas a race-specific QTL on 7HS was identified that was effective only to Psh isolates PSH-72 and PSH-100. A major effect QTL on chromosome 5HL conferred resistance to all Psh races including PSH-72, which is virulent on all 12 stripe rust differential tester lines. The same major effect QTL was also identified in response to leaf rust (17VA12C) suggesting this locus contains several pathogen specific rust resistance genes or the same gene is responsible for both leaf rust and stripe rust resistance. Twelve accessions were highly resistant to both leaf and stripe rust diseases and also carried the 5HL QTL. We subsequently surveyed the physical region at the 5HL locus for across the barley pan genome variation in the presence of known resistance gene candidates and identified a rich source of high confidence protein kinase and antifungal genes in the QTL region.

The performance of sorghum mutant lines resulting from gamma-ray mutation on main diseases

The study aimed to obtain sorghum mutant lines from the Numbu variety resistant to 3 major diseases (leaf rust, leaf spot, and anthracnose). The research was conducted at the ICERI Experimental Garden. The treatments were arranged using a Randomized Block Design with 3 replications with materials tested were five mutant lines derived from a Numbu variety (lines MM-5, MB-3. MB-5. MM-3, MM-4) and resistant comparison varieties (Kawali and Numbu) and check susceptibility lines (Super 2 and line SRN48-1) as a comparison for each disease. The results showed that the five test genotypes had high resistance to 3 main sorghum diseases. The MB-3 and MB-5 mutant lines were resistant to leaf rust and leaf spot Cercospora, and moderately resistant to anthracnose. The lowest infection rate of leaf rust disease was in the MB-5 line, which was 0.0019. This illustrates the low development of rust disease in this line. While the other 3 strains (MM-3, MM-4, and MM-5) consistently reacted moderately resistant to the 2 main diseases of sorghum (rust and anthracnose).

Analysis of Resistance to Fungal Pathogen Hemileia Vastatrix of Liberica Coffee Based on Functional Marker

Coffee Leaf Rust (CLR) disease caused by fungal pathogen Hemileia vastatrix is one of devastated diseases in coffee plants. Disease RGA (resistance gene analog) primer pair CARF 005 has been reported for leaf rust-resistant screening in Arabica coffee and has never been reported in Liberica coffee. Previously, Liberoid Meranti 1 and 2 (Lim 1 and Lim 2) from Meranti Islands Indonesia were officially published by the government as CLR resistant cultivars and adaptive to peat soil. Our study aimed to analyze the resistance of Liberica coffee plants based on functional primer CARF 005. We sampled healthy plants of three Liberica genotypes (Lim 1, Lim 2, Bengkalis) in commercial farmer fields. DNA was extracted from young leaves, amplified and sequenced using CARF 005 primers. All samples generated DNA band about 400 bp. In addition, nucleotide sequences are similar to Arabica putative disease resistance gene. All the three sequences contain NB-ARC conserved domain which contribute to pathogenic-resistant trait. The regions also contain one motif sequence of P-loop/Walker-A domain. Our result confirmed that DNA fragments amplified by CARF 005 are linked to RGA region and eventually we suggested that CARF 005 can be used to identify resistance to CLR in Liberica. It will particularly contribute for supporting Liberica breeding program and conservation of Liberica germplasm

Documentation of multi-pathotype durable resistance in exotic wheat genotypes to deadly stripe and leaf rust diseases

Documentation of multi-pathotype durable resistance in exotic wheat genotypes to deadly stripe and leaf rust diseases

Accumulation of complex oligosaccharides and CAZymes activity under acid conditions constitute the Thatcher+Lr9 defence responses to Puccinia triticina

Puccinia triticina (Pt) is an important pathogen of wheat. While breeding programmes develop resistant wheat cultivars to mitigate the effects of such rust-causing pathogens, the emergence of new rust races with wider virulence mandates the implementation of other control strategies. Our study investigated whether acidic pH conditions affected selected Carbohydrate-Active Enzymes (CAZymes) in Pt-inoculated Thatcher + Lr9 (IR) wheat compared to those found in the Thatcher (IS) wheat. The β-glucosidase and amyloglucosidase activity levels significantly increased in IR compared to the control from 1 to 14 days post-inoculation (dpi). In contrast, activity levels of invertase did not change in the IR wheat relative to the control at 1 and 7 dpi, but were significantly reduced in the IR plants at 14 dpi. The IS had higher activity of all three hexose-producing enzymes under acidic conditions. These enzyme activities could be increased in the IS to produce hexose sugars required by Pt to develop and advance infection. The phenotypic analysis supported this view because leaf rust disease symptoms were only visible in the IS plants. For cell wall loosening-related enzymes, the IR displayed higher activity of exoglucanase, xylanase and peroxidase enzymes compared to IS. The liquid chromatography–mass spectrometry analysis showed IR had higher concentrations of complex oligosaccharides compared to the IS. Thus, we concluded that the higher exoglucanase, xylanase and peroxidase activity could be involved in cell wall loosening under acidic conditions, while oligosaccharides could be building-blocks for synthesizing cell wall barriers that apprehend Pt growth in inoculated Thatcher + Lr9.

Estimation of Inheritance Leaf Rust, Powdery Mildew, Yield and Yield Components in Barley through Generation Means Analysis

The success of breeding program for improvement any crop depends mainly on the available background of the inheritance of the studied traits to be selected. This study was carried out during 2018/2019, 2019/2020 and 2020/2021 grown seasons at the experimental farm of Sakha Agricultural Research Station, Agricultural Research Center, Egypt to estimate the effect of genetic parameters controlling yield and yield component traits in addition severity of leaf rust and powdery mildew disease infection. Six generations (P1, P2, F1, F2, BC1 and BC2) model was used. Results indicated that, mean effect (m) was highly significant in all evaluated crosses for all studied traits. The relative importance of additive and dominance effects differed from trait to another in each cross. For epistatic components, dominance × dominance interaction effects were more effective than other components in most studied traits. Significant or/and highly significant values in desirable direction of heterosis compared to mid and better parent were obtained from most studied crosses in yield and its attribute traits, but it found over mid parents only for cross no.1 in leaf rust and crosses no. 1 and 2 in powdery mildew infection. The estimation of broad-sense heritability showed high values for studied traits and crosses, while narrow-sense heritability and genetic advance from selection ranged from low to medium in most crosses for the agronomic traits, while it ranged from low to high for leaf rust and powdery mildew infection. Finally, the results of this study recommended the barley crosses no. 4 for improve yield potential and resistant to leaf rust and cross no. 5 to improve resistance to powdery mildew, where it had high genetic advance associated with high heritability.

BIOCONTROL OF RUST AND LEAF SPOTS DISEASES OF PEANUT USING CULTURE FILTRATES OF AKANTHOMYCESLECANIIIN NATURALCONDITIONS IN BURKINA FASO

Leaf spots and rust are the most destructive diseases of peanut in Tropical Africa, but it has shown that Akanthomyceslecanii isknown ashyperparasiteof rustandleaf spots fungi. Previous studies have investigated on the use of conidia of A.lecaniiin biocontrol of these diseases. However, the conidia are influenced by temperature and relative humidity, which could result in low efficiency of biocontrol agents in natural conditions. The use of secondary metabolites could help to fight against the plant diseases in natural conditions. Thus, we sprayed peanut plants with culture filtrates from 21-day-old cultures of two strains of A. lecanii grown in potato dextrose broth, to assess their efficiency against leaf spots and rust diseases innatural conditions. A susceptible variety SH470P and a moderately susceptible varietyPC79-79 of peanut to rust and leaf spots diseases were used. Our findings revealed that A. lecanii culture filtrates have significantly reduced the severity of rust and leaf spots diseases in SH470P only. In SH470P, the lowest severity of leaf spots in 2020 (59.26%) and 2021 (48.10%) were recorded in plots sprayed with culture filtrates of A. lecanii. The lowestseverity of rust (29.60%) was recorded in the plots sprayed with the A. lecanii culture filtrates in 2021 in SH470P. From our findings, the use of A. lecanii culture filtrates is a promising alternative in the control of peanut rust and leaf spots. But, further studies are required to determine the effective doses and active secondary metabolites against these diseases.

Diversity of Pathotypes of Leaf Rust (<i>Puccinia triticina</i>) Pathogen in Wheat Crop in Nepal

Wheat (<i>Triticum aestivum</i>) is third most important crop in Nepal after rice and maize. The area of cultivation of wheat is increasing compare to last decade but its productivity could not be increased significantly due to many biotic and abiotic factors. Among them, rust disease is major biotic constraint. Leaf rust (<i>Puccinia triticina</i>) is an economically important disease which occurs on major wheat growing areas of plain and hill of the country. The leaf rust disease monitoring and samples collection were done from 32 districts across the wheat growing area. Rust infected leaves were folded such that rust pustules preserved inside without destroying spores. Excess leaf moisture was removed by keeping them in room temperature with shade drying. Proper dried samples were kept in paper envelop and diagnosed pathotypes at Indian Institute of Wheat and Barley Research (IIWBR), Indian Council of Agricultural Research (ICAR), Regional Station, Flowerdale, Shimla, India. urediospores were revived on 2% water agar and multiplied in susceptible host Agra Local. The fresh urediospores of each sample was collected from susceptible host and inoculated on 5-7 days old seedlings of the standard differential sets. The pathotypes of pathogen was diagnosed on the base on disease infection type showed in the differential sets. Pathotypes 57R39 121R63-1, 21R55, 109R31-1, 121R60-1, 93R15 and 93R39 were commonly observed in both plain and hills. Similarly, the pathotypes 125R23-1, 109R63 and 21R63 were recorded in lower belt whereas, pathotypes 5R13, 49R39, 125R28, 21R31 and 93R47 were found only at hilly regions. The pathotypes 21R55, 121R63-1, 121R63-1and 5R37 were recorded in successive years in most of the wheat growing area. Twenty one different pathotypes of <i>P. triticina</i> occur in different parts of the country. The evolving of different pathotypes diversity of pathogens may be caused by selection pressure due to same genetic materials of wheat genotypes grown in the country and conducive environment. Hence, monitoring rust pathotypes is a one of the necessary step for successful planning to manage the rust disease by developing resistant wheat genotypes.

Pucciniastrum minimum is the causal agent of blueberry leaf rust on different Vaccinium species in Hawke’s Bay, New Zealand

Blueberry leaf rust has become a prevalent disease in New Zealand blueberry production. To identify the pathogen responsible for this disease in the Hawke’s Bay region of New Zealand, leaves showing signs or symptoms of rust infection were collected from three blueberry cultivars (‘Centra Blue’ [Rabbiteye], ‘Georgia Dawn’ [Southern Highbush] and ‘Nui’ [Northern Highbush]) and the pathogen subjected to morphological characterization using both scanning electron and bright-field microscopy. Meanwhile, genomic DNA was extracted from urediniospores of infected leaves collected from cultivar ‘Rahi’ (Rabbiteye) and the Internal Transcribed Spacer (ITS) region was sequenced and compared to the corresponding nucleotide sequence of known rust pathogens. Results from both experiments indicated that Pucciniastrum minimum (syn. Thekopsora minima) was the causal agent of blueberry leaf rust disease in Hawke’s Bay. Next, the level of disease caused by P. minimum was quantified on 23 blueberry cultivars in this region during the 2019 blueberry production season. Here, a total of 20 leaves selected from each cultivar were continually monitored, and the lesion area was calculated using ImageJ based on images taken in the field. Based on this analysis, all leaves were found to be infected by the rust pathogen. However, disease intensity, as a function of the ‘area under the disease progress curve’ (AUDPC) value, was found to be different. This suggests that certain cultivars display a lower disease intensity during the harvest season. Further field assessment covering a whole growing cycle will give a better understanding about blueberry leaf rust infection on these cultivars.

Maize Leaf Disease Identification Based on YOLOv5n Algorithm Incorporating Attention Mechanism

Maize diseases are reported to occur often, and are complicated and difficult to control, which seriously affects the yield and quality of maize. This paper proposes an improved YOLOv5n model incorporating a CA (Coordinate Attention) mechanism and STR (Swin Transformer) detection head, CTR_YOLOv5n, to identify common maize leaf spot, gray spot, and rust diseases in mobile applications. Based on the lightweight model YOLOv5n, the accuracy of the model is improved by adding a CA attention module, and the global information acquisition capability is enhanced by using TR2 as the detection head. The average recognition accuracy of the algorithm model can reach 95.2%, which is 2.8 percent higher than the original model, and the memory size is reduced to 5.1MB compared to 92.9MB of YOLOv5l, which is 94.5% smaller and meets the requirement of being light weight. Compared with SE, CBAM, and ECA, which are the mainstream attention mechanisms, the recognition effect we used is better and the accuracy is higher, achieving fast and accurate recognition of maize leaf diseases with fewer computational resources, providing new ideas and methods for real-time recognition of maize and other crop spots in mobile applications.

Marker-Assisted Recurrent Selection for Pyramiding Leaf Rust and Coffee Berry Disease Resistance Alleles in Coffea arabica L.

In this study, marker-assisted recurrent selection was evaluated for pyramiding resistance gene alleles against coffee leaf rust (CLR) and coffee berry diseases (CBD) in Coffea arabica. A total of 144 genotypes corresponding to 12 hybrid populations from crosses between eight parent plants with desired morphological and agronomic traits were evaluated. Molecular data were used for cross-certification, diversity study and resistance allele marker-assisted selection (MAS) against the causal agent of coffee leaf rust (Hemileia vastatrix) and coffee berry disease (Colletotrichum kahawae). In addition, nine morphological and agronomic traits were evaluated to determine the components of variance, select superior hybrids, and estimate genetic gain. From the genotypes evaluated, 134 were confirmed as hybrids. The genetic diversity between and within populations was 75.5% and 24.5%, respectively, and the cluster analysis revealed three primary groups. Pyramiding of CLR and CBD resistance genes was conducted in 11 genotypes using MAS. A selection intensity of 30% resulted in a gain of over 50% compared to the original population. Selected hybrids with increased gain also showed greater genetic divergence in addition to the pyramided resistance alleles. The strategies used were, therefore, efficient to select superior coffee hybrids for recurrent selection programs and could be used as a source of resistance in various crosses.

Multi-environment phenotyping to identify broad-based, stable resistance in wheat germplasms against leaf and stripe rust diseases

Multi-environment phenotyping to identify broad-based, stable resistance in wheat germplasms against leaf and stripe rust diseases

Model Selection of Hybrid Feature Fusion for Coffee Leaf Disease Classification

Coffee leaf diseases can significantly impact the productivity and quality of the crops. Accurate and timely identification of these diseases is crucial for effective management and control. This paper proposes a hybrid feature fusion approach for identifying coffee leaf disease, including early and late feature fusion. First, we propose several hybrid models to extract the information feature in the input images by combining MobileNetV3, Swin Transformer, and variational autoencoder (VAE). MobileNetV3, acting on the inductive bias of locality, can extract image features that are closer to one another (local features), while the Swin Transformer is able to extract feature interactions that are further apart (high-level features). These differently extracted features contain complementary information that enriches a unified feature map. Second, the extracted images from models are fused in the early fusion network. The early-fusion learner network is deployed to learn the rich information from the extracted feature. The late fusion network is implemented to comprehensively learn the fused feature before a classification network classifies coffee leaf diseases. The proposed hybrid feature fusion approach is evaluated on a challenging, real world Robusta Coffee Leaf (RoCoLe) dataset with various diseases, including red spider mite and leaf rust disease. The results show that our approach, the hybrid feature fusion of MobileNetV3 and Swin Transformer, outperforms the individual models with an accuracy of 84.29%. In conclusion, the hybrid feature fusion approach combining MobileNetV3 and Swin Transformer models is a promising approach for coffee leaf disease identification, providing accurate and timely diagnosis for effective management and control of the diseases in real-world conditions.

Utilization of Plant Waste as A Seed Source to Anticipate Agriculture Global Environmental Challenges and Increase Robusta Coffee Farmers’ Income

Coffee is one of the leading plantation commodities in the world trade area. The utilization of plant waste in the form of water shoots from BP308 robusta coffee is a new innovation in anticipating global environmental changes. The research aims to support seed availability by utilizing wastewater shoots as seed candidates in anticipation of global environmental changes that can provide added value and income for farmers. The research was conducted in the District of Pupuan, Tabanan, Bali. The implementation period is 2 years (2018-2020). This study was designed using a paired experimental design in the form of existing technological innovations and new seed innovations. Data were analyzed using the t test. The results showed that the seeds of existing technological innovations and new innovations were significantly different and not significantly different. Coffee leaf rust disease showed no significant differences in attack rates. Wet weight, total seed weight and shoot oven dry weight were higher in the new innovations respectively 42.14; 51.99 and 40.59%. The added value obtained from wastewater shoots is IDR 10,500.00 per tree. Conversion of added value for each farmer with ownership of 0.3–0.8 hectares (population 300-800) of trees generates an added value of IDR 3,150,000.00 to IDR 8,400,000.00 per year per farmer.

Persistence Patterns and Intensity of Leaf Rust Disease in Chrysanthemum Production Systems

This study aims to determine the conditions of chrysanthemum cultivation, the pattern of distribution of chrysanthemum leaf rust disease (persistence), the development of disease symptoms, and the intensity of chrysanthemum leaf rust disease at the cut flower production center in the Special Region of Yogyakarta (Sleman and Kulonprogo). The results showed that chrysanthemum farming in DI Yogyakarta is cultivated on a flat to hilly topography, and the cultivation method is simple and conventional in a plastic house (gauze). Rust disease caused by Puccinia horiana is found in Sleman and Kulonprogo Regency with varying degrees of severity. Chrysanthemum rust disease has random disease distribution which means that the cause of the disease is dispersed by the wind or by seeds. P. horiana spores are dispersed by the wind and can be caught with Kiyosawa-type spore traps at an altitude of 0.5-1.5 m from the soil surface. The highest intensity of chrysanthemum leaf rust disease is found in dense/lush plantings in susceptible varieties in Pakem Sleman at an elevation of 900 m above sea level by 85% and Samigaluh Kulonprogo at an elevation of 650 m above sea level by 58%.

Mining Sources of Resistance to Durum Leaf Rust among Tetraploid Wheat Accessions from CIMMYT’s Germplasm Bank

A collection of 482 tetraploid wheat accessions from the CIMMYT Germplasm Bank was screened in the greenhouse for resistance to leaf rust disease caused by the fungus Puccinia triticina E. The accessions were screened against two races CBG/BP and BBG/BP in the field at two locations: against race CBG/BP at the Norman E. Borlaug Experimental Station (CENEB) located in the Yaqui Valley in the northern state of Sonora in Mexico during the 2014-2015 growing season; and against race BBG/BP at CIMMYT headquarters in El Batan, Texcoco, in the state of Mexico in the summer of 2015. Among the accessions, 79 durum genotypes were identified, of which 68 continued demonstrating their resistance in the field (past the seedling stage) against the two leaf rust races. An additional set of 41 genotypes was susceptible at the seedling stage, but adult plant race-specific resistance was identified in the field. The 79 seedling-resistant genotypes were tested against 15 different leaf rust races at the seedling stage to measure the usefulness of their resistance in a breeding program. Among the 79 accessions tested, 35 were resistant to all races used in the tests. Two sample sources, CIMMYT (18/35) pre-breeding germplasm and Ethiopian landraces (17/35), showed seedling resistance to all races tested except for seven landraces from Ethiopia, which became susceptible to the Cirno race identified in 2017.

HD 3298: Biofortified, climate-resilient, high-yielding wheat variety for very late sown conditions of North-Western Plains of India

HD 3298 is a biofortified wheat variety having high iron (43.1 ppm) and protein (12.12 %) content with tolerance to terminal heat stress. This variety has a higher yield potential of 47.4 q ha-1 under very late sown conditions. It possesses a high level of resistance against stripe rust, leaf rust, and other important diseases. It has better agronomic attributes and has better adaption to sowing time from timely to very late. This variety has a perfect Glu score (10) with excellent grain quality parameters.

Contrasting coffee leaf rust epidemics between forest coffee and semi-forest coffee agroforestry systems in SW-Ethiopia

Ethiopian Arabica coffee is produced in different agroforestry systems which differ in forest management intensity. In forest coffee systems (FC), coffee shrubs grow naturally in the understory of Afromontane forests with little human intervention, whereas in semi-forest coffee systems (SFC) thinning of the canopy and removal of the understory is applied. Coffee leaf rust (CLR) disease is a growing concern for coffee agroforestry, but to what extent infection pressure is affected by management intensity is poorly known. Here we assessed CLR infection through time across FC and SFC systems in SW-Ethiopia. CLR infection was significantly higher for SFC, with a gradual reduction of this difference during the beginning of dry season (November) through main rainy season of (July). Our findings also demonstrated that CLR infections were significantly lower in the FC system as compared to SFC system in both years 2015/16 and 2020/21. The higher CLR infection was partly explained by lower crown cover and higher human impact. We expect that reduced wind speed and droplet penetration under closed canopies and reduced human-facilitated spore dispersal are the dominating mechanisms behind lower CLR infection in FC systems, yet lower coffee density in FC may also play a role. Overall, our results indicate that although higher management intensity still generally results in higher total yields per hectare, proportionally larger losses due to CLR infection can be expected. Therefore, introducing more coffee genetic diversity, screening resistant coffee varieties and increasing canopy cover in the SFC will mitigate the CLR disease pressure and guarantee the sustainability of higher yields of the system in the future. Also, lower yields in the FC will be rewarded through providing price premiums so that farmers instantly get a higher price for their lower yield, guaranteeing livelihoods.

Pengaruh Jumlah Anakan Terhadap Pertumbuhan dan Hasil Beberapa Genotip Sorgum (Sorghum bicolor (L.) Moench) Lokal Jawa Timur

Sorghum is one type of cereal plant that is easy to cultivate. The use of local varieties in crop cultivation is very good because it can reduce the potential for crop failure. One way to increase crop productivity is by regulating plant density. The aim of the study was to determine the right number of tillers to optimize growth and yield of sorghum from several local genotypes of East Java. The local genotypes used were Sb.Pas, Sb.Spg1 and Sb.Lmg2. The design used was a randomized block design with 9 treatments and 3 (three) replications. The data obtained from the study were analyzed using Variety Analysis, if there was a significant effect, then proceed with the 5% BNT test. The results of the analysis showed significant differences in all components of plant growth and yield observations except for the total dry weight of the plant. While the use of the same genotype showed results that were not significantly different. Better results were obtained with Sb.Spg1 + 3 treatment on the observation of the number of leaves and stem diameter, and Sb.Pas + 2 on the observation of plant height. Observation of the results of the treatment with fewer tillers gave better results in the observation of individual plants but not significantly different from the observations of clump-1 and plot-1. The results of the growth and production of sorghum are influenced by the genotype of the plant, the environment and the attack of Plant Pest Organisms , especially leaf rust disease which is the main disease in sorghum plants.