172 ORAL SESSION 48 (Abstr. 339-345) Vegetable Seeds and Seedlings
During the past 2 decades, automated plug production in the flower seed industry has created important requirements by growers for high-quality flower seeds. Using computerized imaging technology, a new seed vigor testing system, Seed Vigor Imaging System (SVIS), was developed at The Ohio State University. By analyzing the digital images of seedlings, it can detect and measure the length of hypocotyls and radicles separately, and then generate a value for the growth and uniformity each. This system provides a fast, labor-saving and objective approach to measuring seed quality. In this study, its capacity and correlation with field performance was studied and compared with other traditional tests, i.e. standard germination test, germinate rate, and accelerated aging test. Five species (dianthus, cleome, rudbeckia, salvia, and lettuce) were selected and their quality was tracked continuously by SVIS and other mentioned tests. It was found that stressed test (ageing test) was able to detect the quality deterioration earlier than others under ideal conditions, but SVIS could generate much more information, such as the growth, uniformity, and vigor level of the seed lot. Therefore, SVIS following 3-day ageing was developed and shown to be the most sensitive and comprehensive vigor test for those ornamental species mentioned above. Being fast and objective, this system will also benefit the global seed trade by providing a unique quality standard. In addition, it can also be of great usage to seed companies and germplasm centers worldwide for the routine quality track during shipment/storage and inventory management.
Abstract
A 4-channel, microcomputer-based counting system for one method of seed vigor analysis is described. The system consists of a display/interface module and a hand-held probe/switch assembly. The instrument contains 4 count displays and has 2 serial output interfaces to allow recording of the count data. The operator manipulates seeds with the hand-held probe and enters the visually selected seed vigor rating by pressing the appropriate switch on the probe handle. Audible feedback of different pitch for each channel is provided to confirm that the correct switch was depressed. The instrument greatly reduces the amount of labor required to obtain and analyze these data as compared to completely manual methods. Although designed for seed vigor analysis, the instrument could also be used in other applications where counting of items in a mixed sample is necessary.
Tecnologia Agropecuaria, Argentina, to C.A.A., by a grant from Campbell's Seeds. Davis. Calif., and by Regional Research Project w-168. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper
Abstract
Slow and inconsistent germination of cyclamen, Cyclamen persicum Mill., seed appeared to be more related to seed and seedling vigor than to any type of seed dormancy. Pregermination and germination seed treatments such as immersion in hot water, still and flowing water, cool moist storage, alternating temperatures and fungicide treatments were of little value. Treatment with gibberellin (GA) solutions accelerated germination but created an expelled embryo problem. The grower is advised to surface disinfest fully imbibed seed in 5% sodium hypochlorite for 20 sec to 1 min.
Sweet corn (Zea mays L. var. rugosa Bonaf.) seed carrying the mutant endosperm gene shrunken-2 (sh2) are very susceptible to seed rot and pre- and post-emergence damping off. Experiments were conducted to determine if selected organic solvents were suitable carriers for fungicide infusion of sh2 sweet corn seed for improved germination and stand establishment. Seed of `Florida Staysweet' and `Crisp-n-Sweet 710' were immersed in acetone, cyclohexane, decahydronaphthalene (Decalin), dimethylsulfoxide (DMSO), ethanol, or xylene for 5 seconds, 0.25, 0.50, 1.0, 2.0, 4.0, or 8.0 hours, air-dried, and subjected to a cold-stress test. Total germination and percentage of normal seedlings in both cultivars were significantly decreased after 8 hours of immersion in acetone. Average seedling dry weight, however, did not decrease. DMSO was highly toxic to both cultivars. Ethanol increased seed mortality with increasing immersion times. Cyclohexane, Decalin, and xylene caused erratic responses in all measured variables as immersion time increased. In a second experiment, the effects of immersion time up to 4 hours in acetone on germination and vigor of 11 sh2 cultivars were compared. There was no correlation between cultivar germination or vigor and immersion in acetone. Results indicate acetone could be used to infuse fungicides into the seed of some sh2 cultivars without compromising seed germination or vigor. However, each sh2 cultivar must be screened individually to determine if it is a suitable candidate for organic solvent infusion of fungicides.
Sexual seeds of potato (Solanum tuberosum L.) usually emerge poorly under high-temperature conditions (> 25 C). A seedling vigor study was conducted during the warm season (1988-89) in Lima, Peru, and the results of two representative tests. are reported. Two presowing treatments and a rinsed control were compared for seedlingstand establishment in a screenhouse with old (>18 months) and new (> 6 months) sexual seeds of three potato crosses. The treatments consisted of soaking the seed in solutions of KN03 + K3P04 at – 1.0 MPa (priming) and gibberellic acid at 1500 ppm (GA1500). Seedling vigor was lower at 34C (February test) than at 29C (November test). In both tests, overall seedling performance was highest in seed of the cross Atlantic × LT-7. Old seed was more vigorous than new seed, particularly when the crosses Atzimba × R128.6 (B2) and Serrana × LT-7 (Cl) were tested at 34C. Priming increased percentage of early (10 days) emergence over the other treatments at 34C and increased seedling dry weight in both tests. GA1500 increased percentage of final (17 days) emergence in crosses B2 and Cl, as compared to rinsing, except at 29C, where there were no significant differences in old seed. For sowing true potato seed at high temperature, a) the genotype is a crucial factor, b) sufficient seed storage (> 18 months) may be essential, and c) seed priming is more effective than the standard GA1500 treatment.
Abstract
Seed vigor in sweet corn (Zea mays L.) was compared among cultivars with the triple recessive endosperm mutant gene combination amylose-extender (ae), dull (du) and waxy (wx), the shrunken-2 (sh2) gene, their sugary (su) counterparts and an open-pollinated cultivar of normal genotype. Dry weight was significantly lower for F2 kernels of the high-sugar genotypes ae du wx and sh2 than for their su counterparts or the normal cultivar. The endosperm:embryo dry weight ratio was also low in the high-sugar lines due primarily to their small endosperm. Seedling dry weight at 10 days was correlated with endosperm:embryo ratio. Comparisons were made among the cultivars for shoot, radicle, and seminal lateral root growth from intact seeds and from excised embryos on nutrient agar. The normal genotype showed superior seed vigor when evaluated by seedling growth from intact kernels, but not when embryos were grown on agar, suggesting that vigor in normal was due to large endosperms. Respiration rate (μl O2 uptake/kernel·hr) of the germinating seeds did not account for growth differences among the genotypes. Respiration at 24 hr after imbibition was negatively correlated with seedling dry weight at 10 days. Respiration at 48 and 72 hr showed no significant correlations with growth rates. Low seed vigor in high-sugar genotypes apparently was related to their small endosperms. The genotype of the embryo also was important in seedling vigor, but low vigor in high-sugar cultivars could not be attributed wholly to genetic inferiority of the embryo.
Abstract
Germinated spinach (Spinacia oleracea L.) seed (radicle length 3 to 12 mm) were subjected to dehydration under uncontrolled room conditions for 3 to 25 days before planting. Although diminishing over time, some seedlings emerged after all dehydration periods. Seedling height and dry weight responded similarly. Dehydration of germinated seed for ≥15 days was required before seedling emergence was reduced by 50% of that produced by undehydrated germinated seed. Three cultivars responded similarly to length of dehydration period in respect to seedling emergence and vigor.
We thank Kent J. Bradford for providing the seeds for this experiment and James H. Wilson for assistance with Instron analysis. This research was funded in part by USDA research project W-168. Use of trade names does not imply endorsement of