Identification of Novel Sources of Resistance to Seed Weevils (Bruchus spp.) in a Faba Bean Germplasm Collection

Pigeonpea (Cajanus cajan(L.) Millsp. is one of the most important legume crops as major source for proteins, minerals and vitamins, in addition to its multiple uses as food, feed, fuel, soil enricher, or soil binder, and in fencing, roofing and basket making. ICRISAT's genebank conserves 13,632 accessions of pigeonpea. The extensive use of few parents in crop improvement is contrary to the purpose of collecting a large number of germplasm accessions and has resulted in a narrow base of cultivars. ICRISAT, in collaboration with the Generation Challenge Program, has developed a composite collection of pigeonpea consisting of 1000 accessions representing the diversity of the entire germplasm collection. This included 146 accessions of mini core collection and other materials. Genotyping of the composite collection using 20 microsatellite or simple sequence repeat (SSR) markers separated wild and cultivated types in two broad groups. A reference set comprising 300 most diverse accessions has been selected based on SSR genotyping data. Phenotyping of the composite collection for 16 quantitative and 16 qualitative traits resulted in the identification of promising diverse accessions for the four important agronomic traits: early flowering (96 accessions), high number of pods (28), high 100-seed weight (88) and high seed yield/plant (49). These accessions hold potential for their utilization in pigeonpea breeding programmes to develop improved cultivars with a broad genetic base. Pigeonpea germplasm has provided sources of resistance to abiotic and biotic stresses and cytoplasmic-male sterility for utilization in breeding programmes.

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Distribution of discretely scored descriptors in a pure line faba bean (Vicia faba L.) germplasm collection

Euphytica ◽

10.1007/bf00040481 ◽

1991 ◽

Vol 57 (1) ◽

pp. 83-92

Author(s):

L. D. Robertson ◽

M. El-Sherbeeny

Keyword(s):

Vicia Faba ◽

Faba Bean ◽

Germplasm Collection ◽

Pure Line ◽

Vicia Faba L

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Identification of Field Tolerance and Resistance to Mal Secco Disease in a Citrus Germplasm Collection in Sicily

Agronomy ◽

10.3390/agronomy10111806 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1806

Author(s):

Riccardo Russo ◽

Marco Caruso ◽

Carmen Arlotta ◽

Angela Roberta Lo Piero ◽

Elisabetta Nicolosi ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Pathogen Detection ◽

Germplasm Collection ◽

Research Centre ◽

Molecular Screening ◽

Sources Of Resistance ◽

Strong Negative Correlation ◽

Canopy Volume ◽

Mal Secco

Mal secco is a tracheomycotic disease caused by the fungus Plenodomus tracheiphilus (Petri) Gruyter, Aveskamp, and Verkley that has caused severe damage and loss of yield in the citrus industry in the Mediterranean area, for 100 years. While the disease can affect different cultivated citrus species, lemon (C. × limon var. limon (L.) Burm. f.) and citron are the most susceptible. The identification of resistant or field-tolerant clones and hybrids is a major goal for lemon growers and breeders. To identify sources of resistance or tolerance to the disease, we performed a phenotypic survey on a lemon and lemon-like open-field germplasm planted at CREA (Research Centre for Olive, Fruit and Citrus Crops), Italy, in an area with high pathogen pressure. Phenotyping was performed visually, four times, for three consecutive years, on a total of 50 accessions, with two or three replicate trees per accession. Moreover, molecular screening based on real-time PCR was performed, for two consecutive years, on twigs, young leaves, and mature leaves of all plants, to detect the pathogen in the absence of clear symptoms. The accessions were categorized into seven groups based on the presence of visual symptoms, real-time PCR pathogen detection, and canopy volume. The results revealed sources of tolerance in lemon and citron hybrids. The molecular screening identified P. tracheiphilus in all lemon clones, with mean Ct values ranging from 17 to 39. The screening also identified P. tracheiphilus in clones without clear symptoms, indicating their ability to tolerate the disease. Moreover, a strong negative correlation was found between the Ct values in twigs and symptom severity (r = −0.72). This indicates that the DNA from twigs is the most appropriate for use in performing reliable phenotyping of mal secco susceptibility in adult plants. An autotetraploid lemon (Doppio Lentini) seems to be immune to the disease, under natural pressure, since P. tracheiphilus was not detected by real-time PCR and visual screening. Overall, the data obtained are a valuable resource for identifying both the most tolerant lemon varieties suitable for areas with high pathogen pressure and the best breeding parents for the introgression of resistance genes into lemon genotypes.

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Brown Stem Rot Resistance in Soybean Germ Plasm from Central China

Plant Disease ◽

10.1094/pdis.1997.81.8.953 ◽

1997 ◽

Vol 81 (8) ◽

pp. 953-956 ◽

Cited By ~ 21

Author(s):

M. S. Bachman ◽

C. D. Nickell ◽

P. A. Stephens ◽

A. D. Nickell

Keyword(s):

Germplasm Collection ◽

Central China ◽

Stem Rot ◽

Disease Assessment ◽

Sources Of Resistance ◽

University Of Illinois ◽

Brown Stem Rot ◽

Phialophora Gregata ◽

Foliar Symptoms ◽

Resistant Lines

Soybean accessions from China were screened in an attempt to identify unique sources of resistance to Phialophora gregata, the cause of brown stem rot. In 1994, over 500 accessions from the USDA Soybean Germplasm Collection, University of Illinois, Urbana-Champaign, were evaluated in the field at Urbana, IL, for reaction to brown stem rot. The accessions originated from nine provinces in central China and ranged in maturity from groups II to IV. Disease assessment was based on incidence of foliar symptoms and severity of stem symptoms produced by infection with natural inoculum. Based on field results, 64 putatively resistant lines were selected and evaluated in the greenhouse by a root-dip inoculation method. Thirteen accessions with levels of resistance equal to those of resistant standards were identified from five provinces. These lines may have value as donors of unique sources of resistance to brown stem rot.

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Screening of Faba Bean (Vicia faba L.) Germplasm Accessions against Grey Mould Disease Caused by Botrytis fabae Sard

Agricultural Science Digest - A Research Journal ◽

10.18805/ag.d-265 ◽

2020 ◽

Author(s):

Ibrahim Elkhalil Benzohra ◽

Hakima Belaidi

Keyword(s):

Vicia Faba ◽

Faba Bean ◽

Grey Mould ◽

Grain Legume ◽

Sources Of Resistance ◽

Significant Difference ◽

Botrytis Fabae ◽

Vicia Faba L ◽

Faba Beans ◽

Chocolate Spot Disease

Background: Faba bean (Vicia faba L.) is thirst most important grain legume in the world and the first one in Algeria. The chocolate spot disease caused by Botrytis fabae Sard (BF), is the major constraint of this culture in Algeria when caused a destructive damages.Methods: The aim of this study is to find the sources of resistance for Seven varieties of faba beans (Giza 02, Giza 40, Giza 461, Sakha 02, Sakha 03, Precoce de Seville), by using the detached leaflet inoculation test for resistance to the two isolates from BF represent two different regions of northwest Algeria (Mascara and Relizane). Result: A significant difference (P less than 0.05) was observed in the reaction of the varieties which manifest themselves by a different reaction vis-à-vis the isolates of BF. Total sensitivity was observed in the four (4) varieties Giza02, Sakha01, Sakha02 and Sakha03, two (2) varieties (Giza40 and Ziban), are tolerant, while the variety named ‘Precoce de Seville’ showed significant resistance to both isolates from BF. These results showed a similar pathogenic behavior of two isolates of BF and variability in the level of reactions of the varieties of beans. The variety ‘Precoce de Seville’ showed promising results to be valued and cultivated in order to reduce the damage caused by this disease and reduce the use of chemicals.

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Screening Methods and Further Sources of Resistance to Peanut Rust1

Peanut Science ◽

10.3146/i0095-3679-7-1-3 ◽

1980 ◽

Vol 7 (1) ◽

pp. 10-12 ◽

Cited By ~ 13

Author(s):

P. Subrahmanyam ◽

R. W. Gibbons ◽

S. N. Nigam ◽

V. R. Rao

Keyword(s):

Relative Humidity ◽

Irrigation System ◽

Germplasm Collection ◽

Sprinkler Irrigation ◽

Test Material ◽

Screening Methods ◽

Point Scale ◽

Sources Of Resistance ◽

Moderately Resistant ◽

Different Levels

Abstract A germplasm collection of 6000 peanut entries was screened for resistance to rust at ICRISAT, India. Preliminary field screening was done during the 1977 rainy season when a natural epidemic of rust was in progress. The cultivars or lines which were rated between 2 and 5 on a 9-point scale during this screening were further tested during the 1977/78 dry season employing an infector row system of susceptible cultivars and spreader plants systematically interplanted with the test material. High relative humidity was maintained in the field by operating an overhead sprinkler irrigation system. Percentage leaf area damaged on the test material was estimated at 10 day intervals from approximately 90 days after their emergence until harvest. Each entry was also assessed on a scale proposed by Mazzani and Hinojosa. Two land races, NC.Ac. 17090 and EC. 76446 (292) were more resistant than either PI. 259747 or PI. 298115 which were reported resistant by other workers. In addition, NCAc. 17030, NCAc. 17132, NC.Ac. 17129, NC. Ac. 17135 and NC.Ac. 17124 were moderately resistant. Four cultivars or lines with different levels of resistance in the field were tested in the greenhouse at three different stages in development. The results indicated that resistance increased as the plants aged.

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Reaction of faba bean genotypes to Rhizoctonia solani and resistance stability

Horticultura Brasileira ◽

10.1590/s0102-05362011000400008 ◽

2011 ◽

Vol 29 (4) ◽

pp. 492-497 ◽

Cited By ~ 6

Author(s):

Iraildes P Assunção ◽

Liliane D Nascimento ◽

Mércia F Ferreira ◽

Francisco J Oliveira ◽

Sami J Michereff ◽

...

Keyword(s):

Rhizoctonia Solani ◽

Faba Bean ◽

Integrated Management ◽

Phaseolus Lunatus ◽

Sources Of Resistance ◽

Breeding Programs ◽

Rice Grains ◽

Faba Beans ◽

Resistance Stability ◽

Genotype F

The production of faba bean (Phaseolus lunatus) is limited due to the occurrence of Rhizoctonia canker, caused by the fungus Rhizoctonia solani. In order to select materials with potential for use in faba beans breeding programs and/or disease integrated management, 72 genotypes were evaluated and also stability of the disease resistance in relation to different pathogen isolates, inoculum densities and soil type. The seeds were sown in soil infested with the pathogen by the addition of colonized substrate (rice grains). The evaluation of genotypes was done after 15 days, using a note scale to discriminate the genotypes into five reaction classes. None of the 72 genotypes showed immunity to R. solani and only four genotypes (F-42, F-49, F-53 and F-58) behaved as highly resistant. The reactions presented by these genotypes varied according to the R. solani isolate, inoculum density and soil used. The genotype F-58 showed more stable resistance to pathogen isolates and inoculum densities. The genotype F-53 showed resistance stability in soils collected in different locations, remaining highly resistant in all situations. The genotype F-58 did not show high resistance to only one tested soil. Therefore, the genotypes F-58 and F-53 are promising sources of resistance to R. solani and should be indicated in areas infested by the pathogen.

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Reaction of the Core Collection of Peanut Germplasm to Sclerotinia Blight and Pepper Spot1

Peanut Science ◽

10.3146/ps09-001.1 ◽

2010 ◽

Vol 37 (1) ◽

pp. 1-11 ◽

Cited By ~ 16

Author(s):

J. P. Damicone ◽

C. C. Holbrook ◽

D. L. Smith ◽

H. A. Melouk ◽

K. D. Chamberlin

Keyword(s):

Core Collection ◽

Growth Habit ◽

Disease Incidence ◽

Germplasm Collection ◽

Blight Resistance ◽

Sources Of Resistance ◽

Sclerotinia Blight ◽

History Of ◽

Growth Habits ◽

Moderately Resistant

Abstract In 2001, entries from the peanut core collection, a subset of the USDA peanut germplasm collection, were planted in non-replicated plots in a field with a history of Sclerotinia blight caused by Sclerotinia minor. Variability existed among entries for reaction to Sclerotinia blight. Of the 744 entries evaluated, 11% had no disease, nearly 30% had <10% disease incidence, and only 21% had 50% disease incidence or more. Most of the resistant entries had an upright growth habit and were in early and mid-maturity groups. Many of the early maturing entries were susceptible to the foliar disease pepper spot which occurred throughout the study. Entries were selected for further evaluation in replicated plots based on a nil to low (<10%) incidence of Sclerotinia blight, adaptation and/or vigor, and other desirable characteristics such as an intermediate to prostrate growth habit and pepper spot resistance. Selected entries were retested in both 2002 and 2003 (n = 62) and compared to resistant (Tamspan 90), moderately resistant (Tamrun 96), and susceptible (Okrun) reference cultivars. Most entries (55 in 2001 and 46 in 2003) had disease incidence less than Tamrun 96 and similar to Tamspan 90. In 2003 when disease incidence was highest, all 46 entries with resistant reactions similar to that of Tamspan 90 had erect plant growth habits except for entries 208 and 582 which were prostrate, and entries 273, 128, and 804 which were intermediate. Resistance to Sclerotinia blight and yield similar to Tamspan 90, plant habit, and/or reactions to pepper spot and web blotch were used to select the best entries. Entries 208, 128, 804, 582, and 273 combined resistance to Sclerotinia blight, pepper spot, and web blotch with less than erect growth habits. Entry 103 had good Sclerotinia blight resistance and yield, but an upright growth habit. Entry 92 had an upright growth habit and low yield, but good Sclerotinia blight resistance. Entries 92 and 103 had upright growth habits but were among the best entries for resistant to pepper spot and web blotch. Entries 426, 184, and 562 were upright and susceptible to pepper spot, but had resistance to web blotch and the best resistance to Sclerotinia blight. These entries appear to be useful sources of resistance to Sclerotinia blight for breeding programs and for increasing the probability of finding additional sources of resistance in clusters of germplasm identified within the entire USDA collection.

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