Two New Seedling Persian Limes
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CHILDS AND LONG: NEW PERSIAN LIMES 89 worthy substitutes for zineb, particularly where i LITERATURE CITED copper must be employed, although previous 1. Johnson, Roger B., John R. King and J. J. McBride, experiments (Johnson, et al. 6) have shown Soc 70- 38C48tr°1957CltrUS ^ m'te* Pr°C* Fla' State H°rt* 2. Winston, John R., John J. Bowman and W. W. that zineb is somewhat superior to Chloro- Yothers. Bordeaux-oil emulsion. U.S.D.A. Bull. 1178- 1-24. benzilate where no copper is involved. 3. Griffiths, J. T., Jr. and F. E. Fisher. Residues on citrus trees in Florida. Jour. Econ. Ent. 42: 829-833. 1949. Neither zineb nor Chlorobenzilate or Ke- 4. McBride, J. J., Jr. Reaction of zineb with copper com pounds, oil deposits when applied with zineb, and deposits pone have any fumigating action on citrus rust of zineb when applied with a variety of materials. Proc. Fla. State Hort. Soc. 71: 118-122. 1958. mite and are not very effective when applied 5. Johnson, Roger B. The effect of copper compounds where rust mite is numerous. For maximum on control of citrus rust mite with zineb. Jour. Econ. Ent. 53: 395-397. 1960. control, these materials should be applied thor 6. Johnson, R. B., J. R. King and W. L. Thompson. Chem oughly when citrus rust mite first appears. ical control of mites damaging citrus. Fla. Agr. Exp. Sta. Ann. Rept. 1958: 228-229, 1959: 227-228, 1960: in pVess. TWO NEW SEEDLING PERSIAN LIMES J. F. L. Childs7 and W. G. Long8 reach 20 years of age. The most common of these are the so-called 'lime bark disease', xylo- Large seedless limes ((Citrus aurantifolia porosis, psorosis, and gummosis"1 and, "when (Christm.) Swing.)), commonly called Per virus-free trees are found and accepted in sian or Tahiti limes (11), are grown in com the Budwood Certification (registration) Pro mercial quantities only in south Florida.3 W. gram, one of the major headaches of the lime F. Ward (10) wrote that the first Persian producer will be over". Severe damage by lime planting in south Florida was made lime-bark disease has caused more than one near Lake Placid in 1897, and according to grower to remove an entire planting before Col. Alva Lee (5), commercial production the trees were old enough to produce even began about 1928. The origin of the names one normal crop of fruit. Others "quit grow "Persian" and "Tahiti" is not known. If there ing limes and went back to growing citrus", was originally a distinction between them, it as one grower expressed it. has been lost, since they are used interchange That was the situation in 1952 when an ably in Florida today. Incidentally, lime seeds attempt was made to grow virus-free lime trees from Tahiti sent by French officials in 1953 from seed. Although limes are practically seed produced only Key lime plants. less, about one seed to a box of fruit, ar By 1959-60 production of Persian limes in rangements were made with R. W. Kilburn Florida amounted t oapproximately 320,000 of Florida Citrus Canners Cooperative to save boxes (80 lbs.)8 and returned about $880,- the seeds from Persian limes being processed 000.00 to the grower, on the basis of an aver at the Lake Wales plant. Attempts to screen age price of $2.75 per box before harvest. seeds from the pulp were unsuccessful. After From the beginning of commercial produc several days' operation, less than a dozen tion in Florida, Persian limes have been sub seeds were obtained and those were damaged. ject to certain diseases that caused great ex However, approximately 250 lime seeds were pense to growers (3, 5, 7, 9, 10). These obtained by picking over two truckloads of diseases are still a serious problem. W. F. pulp by hand. Ward (10), pioneer nurseryman of Avon When the lime seeds were germinated, less Park, summed up the situation by saying, than half of the seedlings developed Persian "The average life of lime trees is not as long lime leaves. Several developed symptoms as that of orange and grapefruit trees be of lime leaf blotch, evidence that leaf-blotch cause of disease factors. Lime trees are can be transmitted through seed (1, 3). quite susceptible to many bark and virus Twenty-two seedlings with Persian lime- diseases, causing considerable loss before they type leaves were set out near Lake Placid in 1953 for fruiting and observation. By 1957 ^rops Research Division, Agricultural Research Service U. S. Department of Agriculture, Orlando, Florida. most of the seedling trees had fruited, but ^Market Quality Research Division, Agricultural Marketing Service, U. S. Department of Agriculture, Orlando, Florida. the fruits showed little resemblance to the 3lnformation from Charles Townsend, Agricultural Estimates Persian limes of commerce. Several seedlings Division, Agricultural Marketing Service, U. S. Department of Agriculture, Orlando, Florida. were late in fruiting, however, and two of these 90 FLORIDA STATE HORTICULTURAL SOCIETY, 1960 are now producing true Persian lime-type support when first set out. The stakes were fruits. The purpose of this paper is to give a not removed and were later overgrown by the preliminary report of the characteristics of seedlings. None of the budded trees has a those two trees and their fruit. galvanized iron rod by it or protruding from Characteristics of the Seedling Trees it. The two seedling trees are arbitrarily desig Characteristics of the Fruit nated 1 (fig. 1) and 2. Tree 2 is slightly Approximately 25 pounds of fruit was larger than tree 1. Both bear Persian lime-type picked from each seedling tree on August leaves and neither shows symptoms of leaf 11, 1960, when some of the fruits showed a blotch. Both trees are larger than adjacent break in rind color, indicative of maturity. old-line trees budded on Rough lemon ((C. For comparison, a similar lot of fruit was col limon (L.) Burm.)) set the same year, 1953. lected from adjacent budded old-line Persian Nothing is known about the fruiting habits of lime trees. Representative fruits from the three the two seedlings, since both are just begin sources are shown in fig. 2. ning to bear, but the larger tree produced Part of each lot of fruit was withheld for more fruit this season. rind-oil analysis and a preliminary analysis of the fruit, and several small-scale taste tests were performed on the remainder. On Sep tember 10-11 a severe hurricane destroyed the crop and prevented further study of fruit. In the absence of a more thorough study, the results of the preliminary tests are presented. Fruit Analysis Analyses of the three lots show that the to- total soluble solids of fruit from seedling lime trees was slightly higher and the total acid (as citric) was appreciably higher than it was in fruit from budded old-line trees (table 1). Analysis of fruit of old-line budded trees fell within the range reported by S. J. Lynch (6) for limes budded on Rough lemon. The difference between the seedling fruits and those of budded trees may result from the budded limes being on Rough lemon rootstock and partial girdling by lime-bark disease, or the difference between the seedlings and the old-line trees may be real. The fruits from the seedling trees were slightly smaller, and their percent of juice was slightly greater. In either case the differences are small and are probably not important. Fig. 1. Seedling Persian lime tree 1; a budded old-line Taste Tests lime in foreground. Three small-scale taste tests were made. In the first test the fruits were cut into thin Because budded limes are planted among the seedlings, the question has been raised slices. Tasters listed the order of their pref whether a mix-up could have occurred and erence before the origin of the three lots was disclosed. Twenty-four tasters participated. whether trees 1 and 2 are seedlings. That both trees are seedlings is confirmed by the Four could detect no difference between the three lots and 13 of the remaining 20 tasters fact that neither shows a bud-union, a very rated the fruit from budded trees best. The noticeable feature on the adjacent budded fruit from seedling 1 rated second best, and trees. Also each seedling has a heavy gal vanized iron rod protruding from the trunk the fruit from seedling 2 rated last. above the root crown. That happened because In the second taste test, tasters listed their each seedling was tied to a wire stake for preference for limeade made from each of the CHILDS AND LONG: NEW PERSIAN LIMES 91 Fig. 2. Limes harvested from seedling trees 1 and 2 and from adjacent budded old-line lime trees. In the third test, juice from each lot of TABLE 1.—Analyses of fruits from seedling and from old-line fruit was diluted with the same amount of budded Persian lime trees^ water as in the second test, but varying Characteristic Unit Seedling 1 Seedling 2 Old-line amounts of sugar were added to bring each juice sample to approximately the same solids- Fruit weight gm. 98.0 102.0 105.0 acid ratio as follows: 100 ml. of juice was Fruit volume ml. 99.0 103.0 107.0 diluted with 750 ml. of water, and for each Juice ml. 50.0 52.0 55.5 percent of citric acid 10 grams of sucrose was Juice (vol./vol.) % 50.5 49.5 48.9 added. In this test the order of preference was reversed.