Cucurbit Genetics Cooperative Report 19: iii-v (Introduction) 1996
19th Annual CGC Business Meeting (1995)
The 19th annual CGC Annual Business Meeting was held at on Monday, 31 July 1995, in Montreal in conjunction with the annual meeting of the American Society for Horticultural Science. Eighteen members and other interested individuals were in attendance.
Tim Ng presented summary statistics and cost analyses on the eighteen annual CGC Reports,and provided detailed information on CGC Report No. 18 (1995) as well as an update on the forthcoming Call for Papers for CGC Report No. 19 (1996). With increasing paper, printing and mailing costs, the pro-rated annual fee of $7 per year no longer covers the costs of sending the report and additional correspondence to CGC members, so the pro-rated rates will rise to $8 for the 1997 calendar year. Thus, CGC members renewing for the 1996-97 biennium will pay $15 (exclusive of airmail options) while CGC members renewing for the 1997-98 biennium and thereafter will pay $16. This marks the first rate increase since 1988.
The CGC web site was the next topic of conversation. Tim presented background on the history and rationale for creating a CGC web site and placing it on the U.S. Plant Genome server (see CGC Rept. 19:89-90, 1996). He showed sample screenshots, including an article from CGC Report No.18 which had been encoded for the web, and spoke of the potential for archiving old reports but also providing links to other cucurbit-related sites on the web. It was decided that digitization of back issues would begin with the earliest reports, and that eventually all but the most recent five years of CGC reports would be available on the web. Should the time come when all CGC members have access to the Internet, CGC may publish entirely on the web, but in the meantime CGC will still have to publish a printed report every year. However, the most recent gene lists for each of the cucurbit categories will be made available on the web.
Announcements were made on the upcoming Eucarpia meeting on cucurbits, Cucurbitaceae '96 and of plans to update the "other genera" gene list for CGC Report No. 19 (1996). Gary Elmstrom (University of Florida; Pioneer Seeds) recently completed his ten years of service as the CGC Coordinating Committee member for melon (Cucumis melo), and David Wolff (Texas A&M, Weslaco) was elected to replace Gary on the Coordinating Committee.
U.S. Cucurbit Crop Germplasm Committee (CCGC) Update
J.D. McCreight, USDA, ARS, Salinas, California USA
CCGC held its 12th meeting on February 4th, 1996 in Greensboro, North Carolina in conjunction with the Southern Association of Agricultural Scientists Annual Meeting. Susan Webb, (University of Florida) replaced Kent Elsey (entomology) and Alex May, (Rogers Seed Co., Gilroy, California) replaced Jon Watterson (plant pathology).
GRIN is now available on the internet via Gopher (gopher gopher.ars-grin.gov) or anonymous FTP (ftp sol.ars-grin.gov or ftp 220.127.116.11). For more information contact the GRIN Database Manager, Bldg. 003, Room 407, BARC-West, Beltsville, MD 20705-2350 (301-504-5666 or fax 301-504-5536). GRIN has been updated from GRIN2 to GRIN3 and is greatly improved. A Windows version of pcGRIN is now available. A Macintosh version of pcGRIN has finally been elicited from GRIN, and although not as elegant as the Windows version of pcGRIN, it works on the Macintosh! Contact J.D. McCreight if you're interested in the Macintosh version.
One of two Germplasm Evaluation Proposals submitted to NPGS was funded in 1996: Evaluation of Cucumis melo Plant Introductions for Resistance to Monosporscus cannonballus, Investigators: David Wolff and Marvin Miller. Two CCGC members (T.C. Wehner and J.D. McCreight) participated in a cucurbit germplasm collection trip jointly funded by USDA, North Carolina State University and Republic of South Africa from April 24-May 8, 1996. They were hosted by Roger Ellis and Mariana Jooste, RSA, Agricultural Research Council, Plant Genetic resources Unit. The expedition collected approximately 113 mostly wild specimens from the northern areas of the Northern Northwestern and North Cape Provinces.
1996 Watermelon Research Group Meeting
Ray D. Martyn, Dept. Plant Pathology & Microbiology, Texas A&M University, College Station, TX 77845
The 16th Annual Meeting of the Watermelon Research Group was held on February 4th, 1996 in Greensboro NC in conjunction with the Southern Region ASHS and the Southern Association of Agricultural Scientists. Approximately 45 people attended. Unfortunately, the severe ice and snow storm kept many people away, but we still had a good discussion session.
Dr. Tom Kucharek, University of Florida, Gainesville, gave a report on watermelon fruit blotch (FB). He indicated that potential sources of inoculum are infected seed, infected transplants, and watermelon crop debris. Fruit blotch has not been observed on the wild citron and is therefore probably not a potential source of inoculum. Tom also indicated that high humidity in the greenhouse can cause water soaking of the cotyledons similar to that induced by infection and one should be extra careful when rating plants based on water soaking. He also reported that FB increases with increasing temperature. He reported that 50 F it required 8 days for symptoms to develop and only 5 days at 77 F. At 86 F, disease developed the fastest. In regard to seed contamination, apparently the fermentation that occurs naturally in rotting fruit is adequate in eliminating the FB bacterium from seed. They have also conducted comparison testing of the PCR detection method and the grow out method and they indicate that the tests are in fairly good agreement with each other.
Dr. Rick Latin, Purdue University, reported on studies related to inoculum spread and survival. He reported that the FB bacterium could be recovered from buried watermelon rinds for up to 12 months after burying. Studies on relative humidity and disease indicate that more than just high humidity is required to spread the infection. For example, at 95% RH but no overhead irrigation, almost no disease developed in the greenhouse (5-7%). This is compared to 100% disease at 95% RH with overhead irrigation events. At very low RH (35%) disease spread only about 5 cm from the point source. He also reported on studies on the survival and recovery of the FB bacterium. They examined a number of items common to greenhouses (trays, toothpicks, nuts and bolts). At air temperature, the bacterium could be recovered from used seedling trays up to 14 days after the test, but only up to 7 days in new trays. If the trays were stored at 4 C, however, they cold recover the bacterium after 60 days. Rick also showed slides of FB on cantaloupe. Symptoms included sunken pits on the fruit, similar to those caused by anthracnose. On leaves, the symptoms include water soaking and brown, necrotic lesions.
Don Hopkins ,l University of Florida, Leesburg, reported on recovery experiments using a double-labeled antibiotic mutant of the bacterium. He reported that PCR of seed washings and grow out tests gave similar results, although there were some false positives with PCR using nested primers (60 cycles). Treatment of seed with either HCl or fermentation completely eliminated the bacterium from seed. Also most formulations of copper gave adequate control. They also investigated the spread of FB from infected seed in the field by using artificially infested seed at rates of 1 infected seed/ 1000 to 100 infected seed / 1000. In the early planted tests (March), almost all of the plants became diseased with the highest infestation levels around 5-6 weeks after planting. In the later planted test, disease began to show up as early as 2 weeks after planting. Rapid spread was correlated with rain events. There was not much difference in total disease between the 1/1000 and 100.1000 infested seed - both were very high. Don suggested that insects such as leaf miners of aphids may be involved in the spread of FB. He also reported that the wild citron could become infected but he had not seen naturally infected citron in the field. Results of screening over 600 PI accessions for tolerance or resistance indicate that three accessions appeared tolerant (less than a disease rating of 5 on a 1-9 scale).
Dr. Billy Rhodes, Clemson University, Clemson, SC, reported that two PIs were resistant in his test and that dark-colored rinds in Congo were asymptomatic.
Good group discussions occurred throughout the 4 hour meting. If you have any questions related to the above research reports, please contact the person directly. If you do not know their address, phone, e-mail, etc., contact Ray Martyn and he will be happy to provide it for you.
The refreshments for this year's meting were kindly provided by Dr. Glenn Price, American SunMelon, Hinton, OK.
Pickling Cucumber Improvement Committee (PCIC)
The pickling Cucumber Improvement Committee (PCIC) of Pickle Packers International is meeting October 5, 1996, at the Hyatt Regency in Lexington, Kentucky. Titles and abstracts of papers must be submitted by August 1 to Michael Havey (1996 PCIC chair), Department of Horticulture, University of Wisconsin Madison WI 53706.
Proceedings from Cucurbitaceae '94 and Cucurbitaceae '96
The proceedings from the recent Cucurbitaceae '94 (USA) and Cucurbitaceae '96 (Spain) conferences are now available for purchase.
Cucurbitaceae'94 Evaluations and Enhancement of Cucurbit Germplasm, was held on 1-4 November 1994 in South Padre Island, Texas, and was organized by Gene Lester (USDA) and James Dunlap (Texas A&M University). The Proceedings for Cucurbitaceae '94 are available as a book for sale through the American Society for Horticultural Sciences (ASHS). The cost is $20 plus shipping and handling for CGC members ($25 for non-members) plus 4.5% sales tax to Virginia addresses or for sales over the counter. Shipping and handling charges are $5 for domestic orders, $7 for Canadian and Mexican orders, and $10 for all other orders. ASHS can be contacted by phone at (703)-836-4606 (press "0" for operator during business hours). Orders can be faxed,with credit card in formation, to ASHS at (703) 836-2024, or can be mailed to ASHS at 600 Cameron Street, Alexandria, VA 22314-2562 USA.
Cucurbitaceae '96, the VI Eucarpia Meeting on Cucurbit Genetics and Breeding, was held on 28-30 May 1996 in Malaga, Spain, and was organized by M.L. Gomez-Guillamon, C. Soria, J. Cuartero, J.A. Tores and R. Fernandez-Munoz of the Experimental Station La Mayora, CSIC. The Proceedings are now available as a 350 page book entitled Cucurbits Towards 2000 (ISBN 605-5163-6), which is divided into three chapters representing the three meeting sessions: Genetics and Breeding (18 papers), Biotechnology and Physiology (9 papers), and Plant Diseases and Disease REsistances (22 papers). The cost of the book is ESP 5,000 (plus mail expenses of ESP 250), and orders can be sent to M.L. Gomez-Guillamon, E.E. La Mayora-CSIC, 29750 Algarrobo Costa, Malaga, Spain (Fax:34-9-255 26 77, E-mail:email@example.com).
"Melon" Now Accepted by USDA
It's official! The USDA has now declared that the acceptable name for Cucumis melo types is "melon." "Muskmelon" and "cantaloupe" are acceptable synonyms when used to describe muskmelon or cantaloupe types of melons (per USDA). Common sense would dictate that "honeydew" or "winter" or may others are also acceptable, but that the type or kind name is properly "melon." Our thanks go out to Larry Hollar, who in 1989 instigated the effort to request this change by the USDA.
From the CGC Coordinating Committee: The Call for Papers for the 1997 Report (CGC Report No. 20) will be mailed in September 1996., Papers should be submitted to the respective Coordinating Committee members by 31 January 1997, although late submissions may be considered if received prior to our processing deadline. The Report will be published by June/July 1997. As always, wearer eager to hear from CGC members regarding our current activities and future direction of CGC.
From the CGC Gene List Committee: Lists of known genes for the Cucurbitaceae have been published previously in HortScience and in reports of the Cucurbit Genetics Cooperative. CGC is currently publishing complete lists of known genes for cucumber (Cucumis sativus), melon (Cucumis melo), watermelon (Citrullus lanatus), and Cucurbita spp. on a rotating basis.
It is hoped that scientists will consult these lists as well as the rules of gene nomenclature for the Cucurbitaceae before selecting a gene name and symbol. Thus, inadvertent duplication of gene names and symbols will be prevented. The rules of gene nomenclature (published in each CGC Report) were adopted in order to provide guidelines for the naming and symbolizing of genes previously reported and those which will be reported in the future. Scientists are urged to contact members of the Gene List Committee regarding questions in interpreting the nomenclature rules and in naming and symbolizing new genes.
From the CGC Gene Curators: CGC has appointed curators for the four major cultivated crops: cucumber, melon, watermelon and Cucurbita spp. Curators are responsible for collecting, maintaining, and distributing upon request stocks of known marker genes. CGC members are requested to forward samples of currently held gene stocks to the respective Curator.
In CGC Report 18 (1995), an error appeared in the text of the article "Regeneration Response of a Few Genetic Marker Lines and Commercial Cultivars of Cucumis melo L." by Jaagrati Jain and T.A. More (p.48-49). In the "Results" paragraph, it was stated that M4 cotyledonary leaves explant callus exhibited differentiation in the range of "30.5 6.8 percent" and that shoot buds differentiation was observed in "66.7 7.2 percent" of calli. The correct phrases are "30.5 + 6.8 percent" and "66.7 + 7.2 percent" respectively.