Methods
Study Name: Angular Leaf Spot Resistance screening in Cucumis. Resistance to angular leaf spot (Pseudomonas syringae pv. lachrymans, Smith and Bryan) Carsner. Rating scale: 1 = resistant, 9 = susceptible.
Study Name: Anthracnose Resistance screening in Cucumis. Resistance to anthracnose (Colletotrichum orbiculare, Berk. and Mont.) Arx. RACE - 1. Race 1 of anthracnose (Colletotrichum orbiculare). Available from P.H. Williams, Plant Pathology Dept., Univ. of Wisconsin, 1630 Linden Drive, Madison, WI 53706. Also at the Am. Type Culture Coll., 12301 Parklawn Dr., Rockville, MD 20852. Rating scale: 1 = low susceptibility, 5 = medium susceptibility, 9 = high susceptibility.
Study Name: Downy Mildew Resistance screening in Cucumis. Resistance to downy mildew caused by Pseudoperonospora cubensis. Rating scale: 1 = low susceptibility, 5 = medium susceptibility, 9 = high susceptibility.
Year started: //1989 Year seeded: //1989 Year planted: //1989 Year tested: //1989 Year ended: //1989 Evaluator: E. V. Wann, Research Leader, South Central Ag. Research Lab, Lane, Oklahoma. Experiment length: 10 days Comment: Ratings are means of 4 separate observations of each entry made over a period of 10 days as soil tensiometer readings increased from an average of 27 to 53 cb in the test block. His scale is 1 = severe (100%) wilting and 9 = no visual symptoms of stress. These were converted for GRIN definition 1= tolerant, 9 = susceptible.
Year started: //1990 Year seeded: //1990 Year planted: //1990 Year tested: //1990 Year ended: //1990 Evaluator: E. V. Wann, Research Leader, South Central Ag. Research Lab, Lane, Oklahoma.Experiment length: 10 days Comment: Ratings are means of 4 separate observations of each entry made over a period of 10 days as soil tensiometer readings increased from an average of 27 to 53 cb in the test block. His scale is 1 = severe (100%) wilting and 9 = no visual symptoms of stress. These were converted for GRIN definition 1 = tolerant, 9 = susceptible.
Year started: //1991 Year seeded: //1991 Year planted: //1991 Year ended: //1991 Evaluator: E. V. Wann, Research Leader, South Central Ag. Research Lab, Lane, Oklahoma. Experiment length: 10 days Comment: Ratings are means of 4 separate observations of each entry made over a period of 10 days as soil tensiometer readings increased from an average of 27 to 53 cb in the test block. His scale is 1 = severe (100%) wilting and 9 = no visual symptoms of stress. These were converted for GRIN definition 1 = tolerant, 9 = susceptible.
Resistance to fruit rot caused by Rhizoctonia solani. Rating scale: 1 = resistant, 9 = susceptible. Cucumber accessions were evaluated for Rhizoctonia fruit rot resistance by the detached fruit method in which cucumbers were placed on a soil bed infested with Rhizoctonia solani inoculum. Fruits were collected several times per season with the goal of representing each accession with 10 to 30 fruit. A maximum of 10 fruit were collected on one sampling date. Unripe fruits of approximately 45-50 mm diameter were selected, avoiding fruits that were too young or too old. Promising accessions were tested for two or three years to reduce possible environmental influences. Inoculum was produced by growing R. solani mycelium on a substrate of corn meal, sand and horticultural Perlite. The substrate contained 20 g yellow corn meal, 500 mL fine white sand, 500 mL Perlite, and 220 mL deionized water. The mixture was sterilized by autoclaving in polypropylene jars. Three agar plugs of mycelium were added to each jar and incubated for 7-9 days at 270C before use. Transite benches were filled with a 5 cm layer of moist masonry sand, and overlaid with 0.5 to 1 cm of screened, autoclaved field soil. The soil was covered with inoculum at the rate of 175 g per m2, watered lightly and covered with a plastic sheet for 24 hours at 25oC to 27oC. Freshly picked fruit were washed and placed in firm contact with the soil, lightly sprinkled with water and covered with plastic for one night. Disease ratings were made after 6 to 7 days with each fruit scored as resistant (rating =1), intermediate (rating =5), or susceptible (rating =9). A rating of 1 corresponded to no visible infection on the undersurface of the fruit. Fruits with a rating of 5 had restricted crater-like lesions on the undersurface, but little spread. This was considered to be a moderately resistant reaction. A rating of 9 corresponded to an undersurface that was well-rotted. Several accessions showed high levels of resistance in repeated tests, including PI 165509, PI 197086, PI 250147, PI 271328, and PI 390261.
Ref. Theor Appl Genet (1989) 78:119-128. Plant material and sample prep. 753 C. sativus and 4 C. hardwickii currently available PIs were obtained from the Regional Plant Introduction Station, Ames, IA in March 1987. Initially, a random sample of cotyledons was taken from the collection to determine the most appropriate buffer system for electrophoresis of 49 enzymes. Subsequently, a random array of 16% of the accessions was evaluated for variation using these enzymes. The remainder of the collection was then surveyed for potential polymorphisms based on information obtained in this initial evaluation. Cotyledons of 15 individuals from each PI were harvested from 7 to 14-day-old seedlings germinated and grown in vermiculite. Approximately 0.01 g of cotyledonary tissue from each seedling was ground in 0.1 ml of buffer solution containing 0.67g/l TRIS base and 7.02 g/l of TRIS-HCl, pH 7.1, and centrifuged at 100 x g for 5 min. Individuals were sampled and either used immediately or stored at -70 C before horizontal starch gel electrophoresis using the techniques of May et al. (1979) and May (1980). Gels consisted of either 42 g or 56 g of a 1:1 mixture of hydrolyzed potato starch (Sigma Co., St. Louis, Mo.) and Connaught starch (Connaught Laboratories, Willowdale, Ontario, Canada) dissolved in either 300 ml or 400 ml of buffer, respectively. Gel and electrode buffers described by Clayton and Tretiak (1972), Ridgeway et al. (1970), and two by Selander et al. (1971) were used and are referred to as C (pH 6.1 gel and electrode), R (pH 8.5 gel, 8.1 electrode), S-4 (pH 6.7 gel, 6.3 electrode), respectively (Table 1). Filter paper wicks (3 x 8 mm, Schleider and Schuell No. 470) were dipped into the homogenized cotyledon tissue and loaded on the gels. A wick dipped in red food coloring (SCM Corporation, Westlake, Ohio in water, propylene glycol, and artificial colors) was placed at the end of each gel to monitor the rate of movement of the front. To standardize the relative mobilities of the electromorphs (bands), extracts of the C. sativus inbred processing cucumber line GY-14a were loaded on each gel and band mobilities were recorded in relation to GY-14a bands. An electric potential of 125-250 V (<=75 mA) was applied to the gels until the marker dye migrated to within 30 mm of the end of the gel. A gel was sliced horizontally into four or more sections by drawing monofilament thread through it. Modified staining solutions of Allendorf et al. (1977), Brewer (1970), and Shaw and Prasad (1970) were used to visualize banding patterns of 40 enzyme systems (Table 1). Evaluation of germplasm. Isozyme banding pattern were recorded for analysis. The inheritance of the allozymes used in this study are not known. However, based on information from other organisms (Markert 1978; Neale et al. 1984; Chiang et al. 1987), it is possible to assign provisionary genetic bases to the observed eletromorphs. Nomenclature follows a modified form (Staub et al. 1985, 1987) previously described by Richmond (1972), such that loci coding for enzymes (uppercase) are designated by the first letter being uppercase and the rest lowercase. If an enzyme is coded by multiple loci, these are designated by hyphenated numerals and are numbered from most cathodal to most anodal. Alleles of a given locus are numbered from most cathodal to most anodal and enclosed in parenthesis. The most common allele of a locus was designated 100, and all other alleles were assigned a value based on the mobility (mm) of their homomeric protein product relative to that of allele 100. For example, an allele of MDH-3 which had a mobility of 2 mm greater than the most common allele was assigned the designation MDH-3(2)-102. Analytical procedures. Three types of multivariate analyses were utilized to depict affinities and dissimilarities among individual PIs and PIs grouped by geographic region. PIs were placed into 45 groups (regions) according to the source country indicated by the NCRPIS.
Study Name: Target Leaf Spot Resistance screening in Cucumis
Digital image of fruit taken by NCRPIS personnel.
Slides of fruit taken by Dr. Todd Wehner and his graduate students at North Carolina State University of PI-numbered accesions grown for earlieness and yield evaluation in field in North Carolina in 1999. 35mm camera slides of fruit harvested at "once-over harvest stage", digitized, and saved to disc as TIFF and JPEG files. Project supported financially by Augie Gabert, SunSeeds; Stephen King, Seminis Vegetable Seeds; and Gary Taurick, Harris Moran.
Digital image of fruit transverse section taken by NCRPIS personnel.
Scanned image of fruit taken by NCRPIS personnel.
Scanned image of seed or seeds taken by NCRPIS personnel.
Cucumis melo descriptor data recorded during collection maintenance at the NCRPIS farm (42 degrees 3 minutes N latitude 93 degrees 30 minutes W longitude).
Year tested: 1989 Downy Mildew (Pseudoperonospora cubensis) reaction rated as reaction type expressed after artificial inoculation in field (Reference: HortScience 22:638-640, 1987). Cucumis melo var. reticulatus is susceptible to all five described pathotypes of P. cubensis (Thomas et.al., Phytopathology 77:1621-1624); therefore, pathotype 2 was used in the tests. Because all C. melo subspecies are susceptible to pathotype 2, it was considered that susceptibility to one pathotype was indicative of susceptibility to all in these evaluations. Those with RTs of 2, 3, or 4 were retested in artificial inoculations under greenhouse conditions. For the purpose of entry into GRIN, the RT listed for each PI represents the most resistant reation encountered within that PI. RTs standard 1-9 scale where 1 = RT4 = 1mm, circular, chlorotic lesions with necrotic centers and water-soaked margins beneath and extremely limited or no readily apparent sporulation; 3 = RT3 = 3-4mm, irregular to circular, chlorotic lesions with water-soaked margins beneath and sparse sporulation; 7 = RT2= Type "1" lesions, below, mixed with type "3" lesions, above; 9 = RT1 = 10-15mm irregular, chlorotic lesions with abundant sproulation that may extend beyond the apparent margins of the lesions.
Year tested: 1990. Downy Mildew (pseudoperonospora cubensis) reaction rated as reaction type expressed after artificial inoculation in field (Reference: HortScience 22:638-640, 1987). Cucumis melo var. reticulatus is susceptible to all five described pathotypes of P. cubensis (Thomas et. al., Phytopathology 77:1621-1624); therefore, pathotype 2 was used in the tests. Because all C. melo subspecies are susceptible to pathotype 2, it was considered that susceptibility to one pathotype was indicative of susceptibility to all in these evaluations. Those with RTs of 2,3, or 4 were retested in artificial inoculations under greenhouse conditions. For the purpose of GRIN, the RT listed for each PI represents the most resistant reaction encountered within that PI. RTs standard 1-9 scale where 1 = RT4 = 1mm, circular, chlorotic lesions with necrotic centers and water-soaked margins beneath and extremely limited or no readily apparent sporulation; 3 = RT3 = 3-4mm, irregular to circular, chlorotic lesions with water-soaked margins beneath and sparse sporulation; 7 = RT2 = Type "1" lesions, below, mixed with Type "3" lesions, above; 9 = RT1 = 10-15mm irregular, chlorotic lesions with abundant sporulation that may extend beyond the apparent margins of the lesions.
Year tested: 1993/1994 Downy Mildew (Pseudoperonospora cubensis) reaction rated as reaction type expressed after artificial inoculation in field (Reference: HortScience 22:638-640, 1987). Cucumis melo var. reticulatus is susceptible to all five described pathotypes of P. cubensis (Thomas et. al., Phytopathology 77:1621-1624); therefore, pathotype 2 was used in the tests. Because all C. melo subspecies are susceptible to pathotype 2, it was considered that susceptibility to one pathotype was indicative of susceptibility to all in these evaluations. Those with RTs of 2, 3,or 4 were retested in artificial inoculations under greenhouse conditions. For the purpose of entry into GRIN, the RT listed for each PI represents the most resistant reaction encountered within that PI. RTs standard 1-9 scale where 1 = RT4 = 1mm, circular, chlorotic lesions with necrotic centers and water-soaked margins beneath and extremely limited or no readily apparent sporulation; 3 = RT3= 3-4mm, irregular to circular, chlorotic lesions with water-soaked margins beneath and sparse sporulation; 7 = RT2 = Type "1" lesions, below, mixed with type "3" lesions, above; 9 = RT1 = 10-15mm irregular, chlorotic lesions with abundant sporulation that may extend beyond the apparent margins of the lesions.
Results of 1996 spring field planting. Artificial inoculation with Pseudoperonospora cubensis at 25K spores per ml. Reaction rated as reaction type expressed after artificial inoculation in field (Reference: HortScience 22:638-640, 1987). Cucumis melo var. reticulatus is sucspetivle to all five described pathotypes of P. cubensis (Thomas et.al, Phytopathology 77:1621-1624); therefore, pathotype 2 was used in the tests. Because all C. melo subspecies are susceptible to pathotype 2, it was considered that susceptibility to one pathotype was indicative of susceptibility to all in these evaluations. For the purpose of entry into GRIN, the RT listed for each PI represents the most resistant reaction encountered within that PI. RTs standard 1-9 scale where 1 = RT4 = 1mm, circular, chlorotic lesions with necrotic centers and water-soaked margins beneath and extremely limited or no readily apparent sporulation; 3 = RT3= 3-4mm, irregular to circular, chlorotic lesions with water-soaked margins beneath and sparse sporulation; 7 = RT2 = Type "1" lesions, below, mixed with type "3" lesions, above; 9 = RT1 = 10-15mm irregular, chlorotic lesions with abundant sporulation that may extend beyond the apparent margins of the lesions.
Results of 1997 testing. Artificial inoculation with Pseudoperonospora cubensis at 25K spores per ml. Reaction rated as reaction type expressed after artificial inoculation in field (Reference: HortScience 22:638-640, 1987). Cucumis melo var. reticulatus is susceptible to all five described pathotypes of P. cubensis (Thomas et.al., Phytopathology 77:1621-1624); therfore, pathotype 2 was used in the tests. Because all C. melo subspecies are susceptible to pathotype 2, it was considered that susceptibility to one pathotype was indicative of susceptibility to all in these evaluations. For the purpose of entry into GRIN, the RT listed for each PI represents the most resistant reaction encountered within that PI. RTs standard 1-9 scale where 1 = RT4 = 1mm, circular, chlorotic lesions with necrotic centers and water-soaked margins beneath and extremely limited or no readily apparent sporulation; 3 = RT3= 3-4mm, irregular to circular, chlorotic lesions with water-soaked margins beneath and sparse sporulation; 7 = RT2 = Type "1" lesions, below, mixed with type "3" lesions, above; 9 = RT1 = 10-15mm irregular, chlorotic lesions with abundant sporulation that may extend beyond the apparent margins of the lesions.
Results of 1998 testing. Artificial inoculation with Pseudoperonospora cubensis at 25K spores per ml. Reaction rated as reaction type expressed after artificial inoculation in field (Reference: HortScienc 22:638-640, 1987). Cucumis melo var. reticulatus is susceptible to all five described pathotypes of P. cubensis (Thomas et.al, Phytopathology77:1621-1624); therefore, pathotype 2 was used in the tests. Because all C. melo subspecies are susceptible to pathotype 2, it was considered that susceptibility to one pathotype was indicative of susceptibility to all in these evaluatins. For the purpose of entry into GRIN, the RT listed for each PI represents the most resistant reaction encountered within that PI. RTs standard 1-9 scale where 1 = RT4 = 1mm, circular, chlorotic lesions with necrotic centers and water-soaked margins beneath and extremely limited or no readily apparent sporulation; 3 = RT3= 3-4mm, irregular to circular, chlorotic lesions with water-soaked margins beneath and sparse sporulation; 7 = RT2 = Type "1" lesions, below, mixed with type "3" lesions, above; 9 = RT1 = 10-15mm irregular, chlorotic lesions with abundant sporulation that may extend beyond the apparent margins of the lesions.
Study Name: Gummy Stem Blight Resistance Evaluation for Cucumis/Cucurbit Experiment Type: Field/Greenhouse Field Exp. Design: RCB Exp. Location: Ithaca Year seeded: 06/23/1992 Year tested: 08/30/1992 Comment: Plants inoculated with 100,000 sp/ml inoculum on 8/4 and 8/16. Checks included Freeman cuke(R), Gulfcoast(R), Honeydow(S), and pmm339(S). 7 samples of stem and leaf were evaluated for each of 4 reps per accession. Samples were evaluated on a 1-4(stem) or 1-5(leaf) scale and converted to 1 - 9 scale. Disease rate: on the leaf, 1 = no disease, 2 = 1-25%, 3 = 26-50%, 4 = 51-75%, and 5 = 76-100% of leaf area necrotic respectively, on the stem, 1 = no damage, 2 = single lesion < 10 mm in length or composite < 20 mm, 3 = lesions > 20 mm with girdling of the stem, and 4 = the stem withered, 5 = plant dead.
Study Name: Gummy Stem Blight Resistance Evaluation for Cucumis/Cucurbit Experiment Type: Field/Greenhouse Greenhouse Exp. Design: RB Exp. Location: Ithaca Experiment length: 14 days Comment: Plants inoculated with 100,000 sp/ml inoculum, at the 3-4 leaf stage. Plants placed in a mist chamber for 72 hours and evaluated 4 days later. Checks used were PI 140471(R) and Honeydow(S). Samples were evaluated on a 1-4(stem) or 1-5(leaf) scale and converted to 1 - 9 scale. Disease rate: on the leaf, 1 = no disease, 2 = 1-25%, 3 = 26-50%, 4 = 51-75%, and 5 = 76-100% of leaf area necrotic respectively, on the stem, 1 = no damage, 2 = single lesion < 10 mm in length or composite < 20 mm, 3 = lesions > 20 mm with girdling of the stem, and 4 = the stem withered, 5 = plant dead.
Study Name: Gummy Stem Blight Resistance Evaluation for Cucumis/Cucurbit Experiment Type: Field/Greenhouse Greenhouse Exp. Design: RB Exp. Location: Ithaca Experiment length: 14 days Comment: Plants inoculated with 100,000 sp/ml inoculum, at the 3-4 leaf stage. Plants placed in a mist chamber for 72 hours and evaluated 4 days later. Checks used were PI 140471(R) and Honeydow(S). Samples were evaluated on a 1-4(stem) or 1-5(leaf) scale and converted to 1 - 9 scale. Disease rate: on the leaf, 1 = no disease, 2 = 1-25%, 3 = 26-50%, 4 = 51-75%, and 5 = 76-100% of leaf area necrotic respectively, on the stem, 1 = no damage, 2 = single lesion < 10 mm in length or composite < 20 mm, 3 = lesions > 20 mm with girdling of the stem, and 4 = the stem withered, 5 = plant dead.
Study Name: Gummy Stem Blight Resistance Evaluation for Cucumis/Cucurbit Experiment Type: Field/Greenhouse Greenhouse Exp. Design: RB Exp. Location: Ithaca Experiment length: 14 days Comment: Plants inoculated with 100,000 sp/ml inoculum, at the 3-4 leaf stage. Plants placed in a mist chamber for 72 hours and evaluated 4 days later. Checks used were PI 140471(R) and Honeydow(S). Samples were evaluated on a 1-4(stem) or 1-5(leaf) scale and converted to 1 - 9 scale. Disease rate: on the leaf, 1 = no disease, 2 = 1-25%, 3 = 26-50%, 4 = 51-75%, and 5 = 76-100% of leaf area necrotic respectively, on the stem, 1 = no damage, 2 = single lesion < 10 mm in length or composite < 20 mm, 3 = lesions > 20 mm with girdling of the stem, and 4 = the stem withered, 5 = plant dead.
This is the generic evaluation method that can be used for transferring hundred seed weights from the prod.nc7iv table to the prod.ob table. The prod.ob table is where the values for the descriptors are stored.