Stunt Disease Research Articles

Registration of ‘CP 12‐1753’ sugarcane

Abstract‘CP 12‐1753’ (Reg. no. CV‐203, PI 698657) sugarcane (complex hybrid of Saccharum spp.) cultivar was developed through a cooperative research between USDA‐ARS, the Florida Sugar Cane League, Inc., and the University of Florida. It was derived from a polycross made at Canal Point, FL, on 8 Dec. 2010 between a female parent CP 08‐2409 and several male parents. CP 12‐1753 had 11 harvests in Stage 4: plant cane and first ratoon at four locations and second ratoon at three locations. Harvest data showed that CP 12‐1753 had significantly (P ≤ .05) higher cane yield and economic index than the reference cultivars ‘CL 88‐4730’ and ‘CPCL 97‐2730’, respectively, but had significantly lower cane yield in plant cane and lower economic index than the reference cultivar ‘CP 96‐1252’. Freeze tolerance of CP 12‐1753 was lower than the reference cultivars. CP 12‐1753 possesses Bru1, a major gene for brown rust resistance, and showed resistance to brown rust. At the time of release, it was resistant to orange rust, mosaic, and smut. It was moderately resistant to leaf scald and ratoon stunting disease. Considering the agronomic, yield, and disease traits, CP 12‐1753 was released by the Florida Sugarcane Variety Committee in June 2020 to growers for commercial use on mineral (sand) soils.

Ratoon Stunting Disease (Leifsonia xyli subsp. xyli) affects source-sink relationship in sugarcane by decreasing sugar partitioning to tillers

Ratoon Stunting Disease, caused by the bacterium Leifsonia xyli subsp. xyli (Lxx), decreases sugarcane yield by reducing culm growth and tillering, especially in plants with high Lxx titers when the symptoms are more severe. The role of Lxx titers in affecting sugar partitioning and sugarcane growing is still unclear. We hypothesized that high Lxx titers affect source-sink relationship by causing physiological changes in the sugarcane that reduces sugar partitioning to tillers. The study was carried out with susceptible sugarcane genotype CB49260, evaluating physiological traits and biomass production in plants with low (158 ± 28 Lxx cells per 100 ng of plant DNA) and high Lxx titers (2090 ± 385 Lxx cells per 100 ng of plant DNA). Overall, the level of bacterial titers affected sugarcane growth through changes in ethylene level, sugar and biomass partitioning. Plants with high Lxx titers presented a lower number and biomass allocation to tillers than low Lxx titers. Additionally, plants with high Lxx titers had higher biomass allocation to the main culm than low Lxx titers plants due to greater sucrose and starch contents in the main culm caused by the higher number of cell parenchyma, decreased soluble acid invertase activity, and low number of tillers. Changes in sugar and biomass partitioning in plants with high Lxx titers were associated with low release of ethylene in the leaf and culm. Sugarcane with high Lxx titers presented physiological changes that restricted sugar supply for tillering, resulting in a decrease in the number and biomass allocation to the tillers.

Temperature influence on leafhopper population and its potential distribution in predicting spread of chickpea stunt disease in India

Aim: To study the influence of temperature on leafhopper population for predicting potential distribution of chickpea stunt disease. Methodology: Leaf hopper population was sampled at weekly intervals from chickpea experimental plots at Indian Agricultural Research Institute, New Delhi, during Dec-May 2018-2019 and 2019-2020 by using yellow sticky trap. Effect of temperature on leafhopper population was fitted to a non-linear beta model and Briere model by utilizing cardinal temperature for leafhopper growth and reproduction. Daily minimum and maximum temperature data were collected from 146 geo referenced meteorological stations of important chickpea growing states of India. The cumulative temperature indices (MTI) as a measure of monthly leafhopper population was plotted using ArcGis10.0 software. Results: Temperature index estimated as a measure of leafhopper population based on the beta model potential leafhopper population distribution was predicted. Spatio-temporal pattern of vector population indicated that the entire country is favourable for leafhopper growth round the year, except the Northern parts of India during December to February. Interpretation: Since leafhoppers are the natural vectors of virus and phytoplasma pathogens associated with chickpea stunt disease, beta model based prediction of environmental suitability indicates leafhopper as the causative agent for the natural spread of disease in larger geographical area. Spatio-temporal distribution pattern would be useful in predicting the disease spread in different chickpea growing areas for evolving efficient management strategies.

Degradation of hop latent viroid during anaerobic digestion of infected hop harvest residues

The citrus bark cracking viroid (CBCVd) was identified as causal agent for a severe stunting disease in hops. Viroids are highly stable parasitic RNAs, which can be easily transmitted by agricultural practices. Since CBCVd has recently been detected in two European countries a growing concern is that this pathogen will further spread and thereby threaten the European hop production. Biogas fermentation is used to sanitize hop harvest residues infected with pathogenic fungi. Consequently, the aim of this study was to test if biogas fermentation can contribute to viroid degradation at mesophilic (40 °C) and thermophilic (50 °C) conditions. Therefore, a duplex reverse transcription real-time PCR analysis was developed for CBCVd and HLVd detection in biogas fermentation residues. The non-pathogenic hop latent viroid (HLVd) was used as viroid model for the pathogenic CBCVd. The fermentation trials showed that HLVd was significantly degraded after 30 days at mesophilic or after 5 days at thermophilic conditions, respectively. However, sequencing revealed that HLVd was not fully degraded even after 90 days. The incubation of hop harvest residues at different temperatures between 20 and 70 °C showed that 70 °C led to a significant HLVd degradation after 1 day. In conclusion, we suggest combining 70 °C pretreatment and thermophilic fermentation for efficient viroid decontamination.

Plant growth promotion of micropropagated sugarcane seedlings var. Co 412 inoculated with endophytic diazotrophic bacteria and effects on the Ratoon Stunting Disease

Plant growth promotion of micropropagated sugarcane seedlings var. Co 412 inoculated with endophytic diazotrophic bacteria and effects on the Ratoon Stunting Disease

A New Species and Record of Aceria (Acari: Prostigmata: Eriophyoidea) on Weeds from Egypt

Eriophyoids are of great economic importance as pests of weeds, particularly in causing sometimes deformities such as bud galls, stunting, rusting, bronzing, leaf rolling, erineum, blisters, galls, coating, damaged seeds and mosaic virus disease. During the survey of eriophyoid mite fauna from Qualyubia, Cairo and Gharbia governorates in Egypt from 2014 to 2018. One new species and one new record of the genus Aceria from weeds are described and illustrated. Aceria lividus sp. nov., was collected from Amaranthus lividus L. (Amaranthaceae), vagrant on buds and flowers causing stunt and deformation. This species is the first record of eriophyoid mite from the family Amaranthaceae from Egypt. A supplementary description of the first record of Aceria malherbae Nuzzaci, 1985 infested Convolvulus arvensis L. (Convolvulaceae) in Egypt based on females, males and immature. This mite found on upper leaf surface alongside the midrib, causes leaf folding, deformation of flowers and plants and prevent plant reproduction. The two Aceria species indicate that is a promising candidate for the biological control of C. lividus and C. arvensis.

Growth inhibition of phytopathogenic spiroplasmas by membrane‐interactive antimicrobial peptides Novispirin T7 and Caerin 1.1

AbstractSpiroplasma kunkelii and Spiroplasma citri, both helical‐shaped cell wall‐less bacteria, are the causative agents of corn stunt disease and citrus stubborn disease, respectively. Plants exhibiting natural resistance to these phytopathogenic spiroplasmas are currently lacking. Engineering artificial plant resistance using antimicrobial peptides (AMPs) has been conceived as a new approach to control the agronomically important spiroplasmal diseases. In preparation for such task, the present study focused on screening of AMPs that have potentials to curb the growth of S. kunkelii and S. citri. Four AMPs, including Novispirin T7, Caerin 1.1, Tricholongin and Dhvar4, were selected for in vitro growth inhibition test. A liquid assay method was developed for quick qualitative and quantitative evaluations of the AMPs. Our results demonstrated that Novispirin T7 and Caerin 1.1 were able to inhibit the growth of both phytopathogenic spiroplasmas with the efficacy comparable to that of tetracycline. Cell deformations were observed in spiroplasma cultures treated with these two peptides, indicating interactions of the AMPs with the spiroplasma cell membranes. The minimum inhibitory concentrations (MICs) of the AMPs against S. kunkelii and S. citri were determined.

Sistem Pakar Diagnosis Penyakit Stunting pada Balita menggunakan Metode Forward Chaining

Stunting is a condition that occurs in toddlers that fails to grow as a result of nutritional deficiencies so that the height or length of the child's body is not normal for his age. Malnutrition occurs from the moment the baby is in the womb and in the early stages of the baby is born, but the stunting condition is only apparent after the baby is two years old. Currently, the problem occurs a lack of maternal knowledge of the importance of child nutrition during the first 1000 days of life and poor sanitation of the daily environment. Therefore, an expert system is designed to diagnose stunting disease early in children. The method used in expert systems is forward chaining. Expert systems provide diagnostic output as well as user history information, solutions, and processing of user history data. The expert system developed is helpful to help people in diagnosing stunting diseases easily and quickly, where the accuracy system is equal to 91%.

Transmission Effectivity of Rice Yellow Stunt Disease by Imidacloprid-Resistant and Susceptible Brown Plant Hopper

The brown plant hopper (BPH) is a major pest of rice and as a vector of Rice ragged stunt virus (RRSV) and Rice grassy stunt virus (RGSV). Curently, numerous rice yellow stunt disease symptoms are found in the field that caused by the single and simultaneous infection of these two viruses. Brown plant hopper population correlate with the incidence and severity of the disease. Misuse of insecticides, would cause of BPH resistances to imidacloprid. This study aimed to investigate the ability of BPH imidacloprid-resistant and susceptible to transmit of rice yellow stunt disease on rice plants. The variables tested were the acquisition period, inoculation period, number of infesting BPH, and lifespans of the viruliferous BPH that used in this research. Experiments were set as separated Completely Randomized Design with 10 replications for each treatment within an experiment. The results showed that both resistant and susceptible BPH to imidacloprid was able to transmit the virus to healthy plants. The acquisition and inoculation period test showed the BPH could transmit the virus with the shortest acquisition time for 30 minutes followed 24 hours of inoculation, as well as the acquisition time of 10 days with the shortest inoculation time for 30 minutes. Based on the incubation time, symptoms variation, and disease severity, susceptible BPH were more effective in transmitting rice yellow stunt disease than imidacloprid-resistant BPH. Single imidacloprid-resistant or susceptible BPH was proven able to transmit rice yellow stunt disease to healthy plants during its lifespan. Lifespans BPH viruliferous of imidacloprid-resistant were shorter than susceptible, which was 16 days for resistant BPH and 21 days for susceptible BPH.

Identification and characterization of long non-coding RNA and their response against citrus bark cracking viroid infection in Humulus lupulus

Long non-coding RNAs (lncRNAs) are a highly heterogeneous class of non-protein–encoding transcripts that play an essential regulatory role in diverse biological processes, including stress responses. The severe stunting disease caused by Citrus bark cracking viroid (CBCVd) poses a major threat to the production of Humulus lupulus (hop) plants. In this study, we systematically investigate the characteristics of the lncRNAs in hop and their role in CBCVd-infection using RNA-sequencing data. Following a stringent filtration criterion, a total of 3598 putative lncRNAs were identified with a high degree of certainty, of which 19% (684) of the lncRNAs were significantly differentially expressed (DE) in CBCVd-infected hop, which were predicted to be mainly involved in plant-pathogen interactions, kinase cascades, secondary metabolism and phytohormone signal transduction. Besides, several lncRNAs and CBCVd-responsive lncRNAs were identified as the precursor of microRNAs and predicted as endogenous target mimics (eTMs) for hop microRNAs involved in CBCVd-infection.

Characterization of Chickpea Chlorotic Dwarf Virus (CpCDV) Associated with Chickpea Stunt Disease

Background: Stunt disease is becoming the major yield limiting factors for the chickpea production and its occurrence has been reported form different states of India. The symptoms of stunt disease caused by chickpea chlorotic dwarf virus are difficult to distinguish Mastrevirus-infected plant from other disease-causing pathogens. Therefore, it’s an imperative for precise detection of causal agent of the disease for development of management strategy against chickpea stunt.Methods: Survey for the incidence of stunt disease with most characteristic symptoms of leaf reddening and yellow orange typical to Mastrevirus infection was conducted in chickpea fields. The causal agent of the stunt was characterized and described through conventional and virus-specific PCR-based diagnostic technique.Result: The study revealed that maximum of 60% of the chickpea stunt was observed in three districts of Uttar Pradesh with an average incidence of 12.90%. The PCR amplification using CpCDV-specific primers encoding coat protein resulted in an expected amplicon size of 350bp. The comparison of the partial coat protein sequence of virus revealed that maximum homology of 98.70% with previously identified chickpea chlorotic dwarf virus (CpCDV) strains, indicating that CpCDV associated with the chickpea stunt. Based on molecular characterization, chickpea stunt disease caused by Chickpea chlorotic dwarf virus (ssDNA), belongs to the genus Mastrevirus which is also responsible for the lentil stunt disease.

DETECTION AND IDENTIFICATION OF YELLOW MOSAIC STUNT DISEASE ON Petunia sp. USING NESTED PCR METHOD

Yellow mosaic stunt disease was found at some nurseries of Petunia in Sleman, Yogyakarta, also in Muntilan and Magelang Central Java. The disease was very important due to its ability reducing the quality and quantity of Petunia seedlings. The causal agent of the disease may be carried over to imported seeds and necessary to identify as a basic information for developing control strategies. This research was done by mechanical transmission on indicator plants. The observation of the causal agents was conducted using electron microscope with quick dipping method and the molecular detection was done using nested PCR with TobRT up1-TobRT do2 as the external primers and TobN up3-TobN do4 as the internal primers. Mechanical inoculation showed chlorosis symptoms that developed into local spot on Chenopodium amaranticolor as well as mosaic and vein banding on Nicotiana benthamiana. The observation using electron microscope showed rod-shaped virus particles sized approximately 300 nm and by PCR method produced around 568 bp and 400 bp DNA band. Based on the sequence analysis, the disease was caused by Rehmania mosaic virus. This type of Tobamovirus has 96% similarity with ReMV-Japan. ReMV, a plant pathogen which was a member of Tobamovirus that has never been reported in Indonesia. This research was the first report of ReMV in Indonesia infecting Petunia as ornamental plant.

Molecular characterization of chickpea chlorotic dwarf virus and peanut witches\u2019 broom phytoplasma associated with chickpea stunt disease and identification of new host crops and leafhopper vectors in India

An investigation was carried out to identify and characterize the phytoplasma and viruses associated with the chickpea varieties showing severe stunting, leaf reddening, yellowing and phyllody symptoms during the summer season of 2018–2019 and 2019–2020 in eight states of India. The average disease incidence was recorded from 3 to 32% in different states. The presence of chickpea chlorotic dwarf virus (CpCDV) was confirmed in thirty-seven chickpea samples by amplification of CpCDV coat protein gene and sequence comparison analysis. No record of association of luteovirus, polerovirus and cucumovirus could be detected in any of the symptomatic chickpea samples by RT-PCR assay. Brassica nigra, B. juncea, Lens culinaris, two weeds (Heteropogan contartus, Aeschynomene virginica) and one leafhopper (Amarasca biguttula) were identified as new putative hosts for CpCDV. Association of peanut witches’ broom phytoplasma was confirmed in twenty-eight chickpea samples, Sesamum indicum, five weeds hosts and two leafhopper species (Exitianus indicus, Empoasca motti) using nested PCR assays with primer pairs P1/P7 and R16F2n/R16Rn. The results of phytoplasma association in plants and leafhopper samples were further validated by using five multilocus genes (secA, rp, imp, tuf and secY) specific primers. Sequence comparison, phylogenetic and virtual RFLP analysis of 16S rRNA gene and five multilocus genes confirmed the identity of association of 16SrII-C and 16SrII-D subgroups of phytoplasmas strain with chickpea samples collected from Andhra Pradesh (AP), Telangana, Karnataka, Madhya Pradesh, Uttar Pradesh and New Delhi. Mixed infection of phytoplasma (16SrII-D) and CpCDV was also detected in symptomatic chickpea samples from AP and Telangana. The reports of association of 16SrII-C subgroup phytoplasma in chickpea and 16SrII-D subgroup phytoplasma in C. sparsiflora and C. roseus are the new host records in world and from India, respectively.

Impact of the colonization of Leifsonia xyli subsp. xyli in a susceptible sugarcane genotype on water status and physiological traits

Leifsonia xyli subsp. xyli (Lxx) is a pathogenic bacterium that causes Ratoon Stunting Disease (RSD) in the sugarcane crop. Disease symptoms caused by Lxx have been associated with hormonal imbalance, which may be intensified when plants are under water deficit conditions. However, up to date there are no studies showing that Lxx colonization decreases water status in sugarcane. The objective of this study was to evaluate the effect of water status and physiological traits of sugarcane colonized by Lxx under irrigation and water deficit conditions. We inoculated cuttings of the sugarcane genotype CB 49260 with Lxx using four treatments: i) healthy plants fully irrigated, ii) healthy plants under water deficit, iii) plants inoculated with Lxx fully irrigated, and iv) plants inoculated with Lxx under water deficit. Lxx inoculation in sugarcane did not affect relative water content (RWC) in the leaves, independently of the water conditions tested. For gas exchange and fluorescence traits, we did not identify differences between plants inoculated with Lxx and healthy plants. As expected, plants under water deficit conditions decreased RWC, CO2 assimilation, stomatal conductance, transpiration and fluorescence traits, and increased soluble amino acids and proline contents in the leaves. Lxx inoculation increased amino acids and proline contents in plants under water deficit conditions. Therefore, the results indicated that sugarcane colonized with Lxx did not change plant water status independently of the water conditions during the entire growing season.

DETECTION AND IDENTIFICATION OF YELLOW MOSAIC STUNT DISEASE ON Petunia sp. USING NESTED PCR METHOD

Detection and identification of yellow mosaic stunt disease on Petunia sp. using nested PCR method. Yellow mosaic stuntdisease was found at some nurseries of Petunia in Sleman, Yogyakarta, also in Muntilan and Magelang Central Java. Thedisease was very important due to its ability reducing the quality and quantity of Petunia seedlings. The causal agent of thedisease may be carried over to imported seeds and necessary to identify as a basic information for developing controlstrategies. This research was done by mechanical transmission on indicator plants. The observation of the causal agents wasconducted using electron microscope with quick dipping method and the molecular detection was done using nested PCRwith TobRT up1-TobRT do2 as the external primers and TobN up3-TobN do4 as the internal primers. Mechanical inoculationshowed chlorosis symptoms that developed into local spot on Chenopodium amaranticolor as well as mosaic and veinbanding on Nicotiana benthamiana. The observation using electron microscope showed rod-shaped virus particles sizedapproximately 300 nm and by PCR method produced around 568 bp and 400 bp DNA band. Based on the sequence analysis,the disease was caused by Rehmania mosaic virus. This type of Tobamovirus has 96% similarity with ReMV-Japan. ReMV, aplant pathogen which was a member of Tobamovirus that has never been reported in Indonesia. This research was the firstreport of ReMV in Indonesia infecting Petunia as ornamental plant.

Registration of ‘CP 11‐1314’ sugarcane

Abstract‘CP 11‐1314’ (Reg. no. CV‐196, PI 693071) sugarcane, a complex hybrid of Saccharum spp., was developed through cooperative research conducted by the USDA‐ARS, the University of Florida, and the Florida Sugar Cane League, Inc.; it was released to Florida growers in June 2018 for cultivation on organic soils and further recommended in June 2019 for sand soils. This cultivar was derived from a polycross between CP 05‐1451 and a mixture of potential pollen donors. CP 11‐1314 was selected for release based on high cane yield and acceptable sucrose content. In addition, CP 11‐1314 displays good ratooning ability (particularly on muck soils), minimal sucrose decrease following freezing temperatures, and overall disease resistance. CP 11‐1314 is positive for the Bru1 locus, which confers resistance to brown rust, and is resistant or moderately resistant to all other sugarcane diseases of concern in Florida, including ratoon stunt disease, leaf scald, mosaic, and orange rust.

Registration of ‘CP 11‐1956’ sugarcane

AbstractSugarcane (a complex hybrid of Saccharum spp.) cultivar ‘CP 11‐1956’ (Reg. no. CV‐198, PI 695075) was released in June 2018 for commercial cultivation on organic (muck) soils in Florida. This cultivar was developed through a collaborative cultivar development program of the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, based at Canal Point, FL. The parents of CP 11‐1956 are CP 03‐2188 (female) and CP 01‐2459 (male). CP 11‐1956 was released because of its excellent combination of disease resistance against major sugarcane diseases and cane and sugar yields that are similar to reference cultivars that are major commercial cultivars in Florida. CP 11‐1956 is considered resistant to brown rust, orange rust, ratoon stunting disease, smut, and mosaic. This cultivar is also moderately resistant to leaf scald and yellow leaf disease. Cane and sugar yields of CP 11‐1956 are similar to the reference cultivar CP 96‐1252 that has occupied the largest acreage in Florida for several years. CP 11‐1956 had poor freeze tolerance compared with several reference cultivars.

Identifying genomic regions controlling ratoon stunting disease resistance in sugarcane (Saccharum spp.) clonal F1 population

The ratoon stunting disease (RSD) of sugarcane, caused by the bacterium Leifsonia xyli subsp. xyli, is one of the major concerns to sugarcane production and breeding programs worldwide. Due to no obvious external symptoms, RSD cannot be easily detected by the growers, hence has reduced the world’s sugarcane production significantly. This study aimed to identify quantitative trait loci (QTL) associated with RSD resistance and to assist in the development of linked molecular markers for marker-assisted breeding to minimize the reduction in sugarcane yield by the RSD infection. A set of 146 individuals derived from a self-crossing of CP80-1827 were evaluated for RSD resistance in a mechanically duplicated inoculated field trial from 2014 to 2017 using tissue blot immunoassay. Leveraging the genetic data and the four years phenotyping data of CP80-1827 selfing population, linkage map construction and QTL analysis were conducted based on clonal F1 and F2 mapping population types with GACD V.1.2 and IciMapping V.3.3, respectively. A total of 23 QTL associated with RSD resistance were identified, which explained 6% to 13% of the phenotypic variation with the two types of software. A total of 82 disease resistance genes were identified by searching these 23 QTL regions on their corresponding regions on the Sorghum bicolor genome (44 genes), sugarcane R570 genome (20 genes), and S. spontaneum genome (18 genes), respectively. Compared with IciMapping V.3.3, GACD V.1.2 identified more major (6 vs. 3) and stable QTL (2 vs. 0), and more disease resistance genes (51 vs. 31), indicating GACD V.1.2 (clonal F1 mapping type) is most likely to be more efficient than IciMapping (F2 mapping type) for QTL analysis of a sefling population or clonal F1 population in clonal species. The identified QTL controlling RSD resistance along with the associated SNP markers will assist sugarcane molecular breeding programs in combating this disease.

Registration of ‘CP 10‐1716’ sugarcane

Abstract‘CP 10‐1716’ (Reg. no. CV‐195, PI 691536) sugarcane (a complex hybrid of Saccharum spp.) was released (7 June 2018) through cooperative research by the USDA–ARS Sugarcane Field Station at Canal Point, the University of Florida, and the Florida Sugar Cane League, Inc. CP 10‐1716 is recommended for use on mineral (sand) soils in Florida. CP 10‐1716 resulted from polycross X07‐1257 (CP 00‐2180 × Mix07Q; male parent is unknown). Replicated trials at four sand soil locations, with yield data from 12 harvests and three crop cycles (i.e., plant cane, first ratoon, and second ratoon) showed that CP 10‐1716 had cane and sugar yields, and profitability (economic index, US$ ha−1), that were similar to check cultivars (‘CL 88‐4730’ and ‘CP 96‐1252’). Commercial recoverable sucrose (CRS) in CP 10‐1716 was significantly lower than the check averages, but the early CRS was not significantly different from the mean of the checks. The economic index for CP 10‐1716 vs. the mean of the checks was $2490 vs. $2445 ha−1, respectively, with CP 10‐1716 showing no significant difference from the mean of the checks. CP 10‐1716 was rated as moderately resistant to ratoon stunt disease and resistant to brown and orange rust, mosaic, smut, leaf scald, and yellow leaf disease on sand soils. CP 10‐1716 is positive for the Bru1 molecular marker that is one of the indicators for brown rust resistance. CP 10‐1716 has low to moderate freeze tolerance as it relates to sucrose degradation.

Pola Segregasi Sifat Ketahanan Terhadap Soybean Stunt Virus dan Keragaman Genetik FAMILI F2:3 HASIL PERSILANGAN VARIETAS ORBA DAN GALUR B3570

Segregation pattern of the Soybean Stunt Virus resistant character and genetic diversity of F2:3 families derived from crosses between Orba and B3570. Soybean stunt disease caused by SSV (Soybean Stunt Virus) is the most destructive soybean disease in Indonesia. This research was conducted from October 2005 to June 2006 at experiment station of Lampung University. The aims of this research were to evaluate the segregation of resistant characters and total genetic diversity of eight populations of F2:3 families. Experiment was arranged in a randomized complete block design with three replications. The resistance was evaluated based on the score of disease severity. The results showed that the resistant characters segregate 1:2:1 to susceptible, moderately resistant, and resistant, respectively based on the segregation pattern. The resistant character was controlled by single gene and the action of the gene is noncompletely dominant gene. Eight populations of F2:3 families have high diversities on the yield and yield components.