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February 1993 Vol. 4, #1 National Symposium For Stand Establishment In Horticulture Crops Participants from 22 states and 6 countries attended the Third National Symposium for Stand Establishment in Horticultural Crops on November 16 - 20 in Fort Myers, FL. The ASHS cosponsored symposium boasted 138 registrants including top professionals from the seed industry and universities world wide. Forty-four oral presentations and 4 posters offered information on the latest research and practical applications in the field of stand establishment. Oral presentations were divided into three categories: Seed (quality, technology, semisweet corn), Transplants (conditioning, production, establishment), and the Field (establishment, mulches). Topics in the Seed sessions included meteorological conditions and seed health, squash germination temperature relationships, phenolic leakage and seed quality, thermal inhibition in tomato seed, seed borne diseases, various aspects of seed priming, and the use of biological agents t o improve stand establishment. The Transplant sessions included talks on nutritional conditioning in watermelon and pepper, plant growth and water status of Jalapeno pepper, brushing for height control in cucurbits, pepper planting depth, storage of field grown cabbage transplants, tomato performance under hot caps, and tomato growth from a 406 cell container. Field sessions highlighted broccoli induced allelopathy in Cole crops, row-cover insect exclusion, variations on bell pepper spacing, cover crops, organic mulches and vegetable seedlings in composts. Two field tours complimented the talks. A half day tour to the Southwest Florida Research & Education Center demonstrated "typical" stand establishment problems in south Florida and featured ongoing work in transplant production. The demonstrations included examples of misuse of standard subsurface seepage irrigation (typical of south FL), bed preparation problems, salt damage, fertilizer leaching, fertilizer band movement, transplant damage from heat and plastic, and transplant research on ebb and flow irrigation, composted media, super absorbents, chlorine disinfectants, age and cell size, "budless" plants, and root ball death. A visit to CollierPac, a state of the art tomato packing facility, rounded out the afternoon. A full day tour on Nov. 20 visited 6 L's farm #7 to view overhead irrigation transplant production, field pepper production and 1,400 acres of computer driven drip irrigation. Rogers NK hosted the group and discussed their role as a player in the seed industry with demonstrations on tomato abnormalities, and new introductions from pepper, watermelon, and squash breeding lines. Collier Farms, Inc. reviewed SW FL potato production and CollierGro addressed ebb and flow transplant production to conclude the tour. The proceedings (336 pages) of the symposium are a valuable asset to grower, pathologist, seedsman, horticulturist and industry support personnel alike. Copies can be obtained by making a check payable for $13.00 to SW FL Vegetable Committee, P.O. Drawer 5127, Immokalee, FL 33934. For multiple or out-of-country copies please FAX us (813-657-5224) for accurate pricing. "Budless" Tomato Plants ... Nitrogen In The House & Yield In The Field "Topless", " BudIess", "Headless" plants, no matter what you call them, we've all seen those nasty little plants without a terminal bud. The development of budlessness "appears" (?) to be of plant house origin but very often goes unnoticed by the plant house grower. The bud may be visible, but has simply ceased to function. All gradations of this condition can occur from complete terminal budless-ness to suppressed terminal meristematic growth. These plants seem normal when received by the consumer, but after two to three weeks in the field it becomes apparent that terminal meristematic growth is not occurring. This condition almost always manifests itself at the seventh node, the area around which the "fork" will occur (the fork being the sucker subtending the first flower cluster). A survey of state vegetable specialists and industry vegetable breeders revealed little knowledge of the cause of budless-ness. Surveys of commercial plantings have shown the incidence to range from 10% to over 90%. Compounding the problem is the fact that this phenomenon seems to occur mostly in mid-Fall production! Therefore it appears to be only a Florida problem. The field portion of the problem occurs at pruning. Generally, the first pruning removes all suckers. If this practice is enforced with budless plants, the plant will be left without supportive sucker growth to establish a fruit load. If a second pruning is attempted, similar circumstances occur. From plant house studies conducted in Sept. and Oct. '92 to determine nitrogen rates for use in ebb & flow irrigation new information has been generated. The first study (harvested in Oct.) was carried out on 3-week old tomato plants fertilized weekly with Nutrileaf 20-20-20 at 5.675 grams per gallon. These plants were subjected to a complete Hoaglands solution with the only source of N coming from ammonium nitrate. The treatments consisted of N at 0, 15, 45, and 75 ppm applied daily. Surprisingly after 3 additional weeks at these N regimes budlessness increased with decreasing N! Figure 1 shows 0 N resulted in 36% budless, while 75 ppm N resulted in 2.3% budless plants. The response was essentially linear, but a quadratic fit also seemed appropriate. A second study (harvested in Nov.) utilized N rates of 0, 15, 30, 45, 60, and 75 ppm. These plants were grown for the full six weeks on the N regimes applied daily. While absolute budlessness was reduced in this trial (only 26% in the 0 N treatment), retarded, bud growth incidence was much greater (Fig. 2). A quadratic response seems more appropriate here, and since growers would never use 0 N, the response is essentially linear. How these data impact commercial production is still a question. It has been suggested that the practice of "flushing" plug fertilizer to reduce stretch may essentially be sufficient to result in 0 N at critical periods for growth. Why this phenomenon occurs only in fall production is also still unanswered, but light and water stress have been suggested as other physiological parameters to be considered. Regardless of why budlessness is occurring we still need to know what pruning technique to suggest to growers receiving budless plants. A cooperative study with Glades Crop Care implemented in a predominantly budless field in Nov. has given us some insight. Budless plants were pruned of 0, 2, and 4 suckers and yields were compared to "normal" plants. Unfortunately, as with many studies in commercial fields, we were only able to obtain info from one harvest and that harvest was almost solely extra-large fruit. Essentially, total yield (Fig. 3) was greatest for the normal plants (7.6 fruit/plant), and least for the budless plant pruned of 4 suckers (4.4 fruit/plant). The 2 suckers pruned yield was statistically similar to the normal plant, but the 0 suckers pruned yield was lower ... ? By virtue of its reduced fruit load however the budless plant pruned of 4 suckers had the greatest individual fruit weight (9.6 oz/fruit) vs. the normal plant (8.6 oz/fruit). Cull weights were similar among treatments. These data are quite variable, need further verification, and are not to be taken as gospel. However, they do give us some info to go on. At this point we would not recommend pruning more that 2 suckers from budless plants or yield reductions could become apparent. We will keep you posted on further developments in this area. Until next time, Charles Vavrina
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