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Abstract
‘TropicSweet’ peach is released jointly by the Texas Agricultural Experiment Station of the Texas A&M Univ. System and the Florida Agricultural Experiment Station of the Univ. of Florida.
Abstract
Ten-year tests in 8 locations in the Lower Rio Grande Valley showed that grapefruit (Citrus paradisi Macf.) trees on Swingle citrumelo [C. paradisi x Poncirus trifoliata (L.) Raf.] rootstock grew very poorly on heavy clay soil; trees on sour orange (C. aurantium L.) were much less affected. Trees propagated from a single mother tree of an old-line red grapefruit selection on Swingle citrumelo were stunted and had severe bud union crease, whereas trees propagated from a nucellar California Experiment Station (CES) #3 ‘Redblush’ source were large and productive. Old-clone trees on sour orange also were smaller than CES #3 ‘Redblush’ trees, but showed no bud union crease.
Eighteen citrus rootstock seedling lines were tested for their tolerance to Fe chlorosis using sand culture. Potassium carbonate was used to induce Fe-deficiency chlorosis. Chlorosis was quantified by 1) visual ratings, 2) SPAD-502 chlorophyll meter readings, 3) leaf chlorophyll concentration, 4) leaf active Fe, and 5) leaf total Fe. The first four criteria were well correlated among each other but not with leaf total Fe. Although any of the first four measurements could be used to quantify chlorosis, visual ratings and SPAD-502 readings were more convenient. The rootstock that have been reported to be tolerant or very susceptible to Fe chlorosis in calcareous soils were rated similarly for tolerance to bicarbonate-induced Fe chlorosis. Nontrifoliate types such as Texas sour orange (C. aurantium L.), Cleopatra mandarin (C. reticulata Blanco), Vangasay lemon (C. limon Burro.), and Ridge pineapple x Milam 1578-201 (C. sinensis L. Osbeck x C. jambhiri) were tolerant to moderately tolerant. Although most of the trifoliate hybrids tested were moderately susceptible to very susceptible, Smooth Seville x Argentine trifoliate {[C. grands (L.) Osbeck x C. aurantium] x Poncirus trifoliata (L.) Raf.} and F-81-12 citrange (C. sinensis x P. trifoliata) exhibited relatively high tolerance to lime-induced Fe chlorosis.
Abstract
Five-year mean yield from 14-year-old nucellar ‘Redblush’ (CES #3) grapefruit (Citrus paradisi Macf.) on 22 rootstocks was significantly greater on Swingle citrumelo 4475, C58-229 (Rangpur lime × Troyer citrange) and Troyer citrange than on the standard sour orange used in Texas. Percentage of commercially desirable fruit (size 96 and larger) was greatest on rootstocks having the highest yield. The yield of trees on nine rootstocks may have been affected by phytophthora foot rot.
Abstract
A portable unit for determining leaf freezing points (LFP) of citrus leaves is described. This unit has been used extensively in citrus and is suitable for exotherm analysis of a variety of plant species and tissues.
Abstract
‘FlordaGrande’ peach is released jointly by the Texas Agricultural Experiment Station of the Texas A&M Univ. System and the Florida Agricultural Experiment Station of the Univ. of Florida.
Abstract
Nuclear magnetic resonance (NMR) H resonance signals of water in deuterated disks from acclimated and nonacclimated satsuma (Citrus unshiu Marcovitch) leaves appear to be a measure of bound water. The D resonance signal was lost when initial freezing occurred along with a partial loss in H resonance, which was attributed to D2O and bound H2O forming ice. Acclimated tissues retained a larger percentage of unfrozen H2O at initial freezing and at several subfreezing temperatures, suggesting that changes in H2O binding occur during cold acclimation. Further, NMR line widths of nonacclimated leaf tissue increased abruptly during freezing and only gradually in acclimated leaf tissue, suggesting increased binding structure of H2O molecules of the bound fraction and cellular constituents in acclimated tissue. Portion of total H2O replaced with D2O was 69% in both, suggesting this portion was free water.
Japanese cedar [Cryptomeria japonica (Thun. ex L.f.) D. Don. (Taxodiaceae)] cultivars have become quite popular in the U.S. landscape and nursery industries. Their popularity is expected to increase as more attractive and adaptable horticultural selections gain recognition. Taxonomic problems include an inadequate inventory of selected variants cultivated in the United States, instability of names at the infraspecific taxonomic level, poor descriptions of the cultivars, and a lack of representative specimens and identification aids to help horticulturists identify unknown specimens. A study of Cryptomeria japonica cultivated in the United States is needed to address these problems.
Japanese cedar, Cryptomeria japonica (Thunb. ex L.f.) D. Don [Cupressaceae Bartling, formerly assigned to Taxodiaceae Warm.] is increasing in popularity as a landscape plant in the eastern United States. A taxonomic study of cultivars grown in the eastern United States was conducted. Forty-five cultivars were recognized. Each cultivar bears synonymy, a quantitative morphological description newly described from field data, herbarium vouchers, references to original literature and observational notes. A glossary of taxonomic terms relevant to Cryptomeria is presented. A taxonomic key is presented for segregation of cultivars that should assist professional plantsmen in identification of taxa cultivated in the eastern United States.