Sixteen cultivars of citrus (Citrus spp.) and close citrus relatives were planted in Savannah, Georgia to evaluate their potential as fruiting landscape trees in an area that routinely experiences minimum temperatures of 15 to 20 °F (-9.4 to -6.7 °C) during winter. Three to six trees of each cultivar were planted in 1998, and stem dieback and defoliation data were collected in 1999, 2001, and 2002. During the 4 years of the study, air temperatures fell below 32 °F (0.0 °C) 27 to 62 times per season, with absolute minima ranging from 13 to 18 °F (-10.6 to -7.8 °C), depending on year. In general, kumquats (Fortunella spp.), represented by `Meiwa', `Nagami', and `Longevity', were completely killed (or nearly so) in their first year in the field after air temperature minima of 13.5 °F (-10.28 °C). Others experiencing 100% dieback were `Meyer' lemon (Citrus limon × C. reticulata) and `Eustis' limequat (C. aurantifolia × Fortunella japonica), which were tested twice during the study. Kumquat hybrids, including procimequat [(C. aurantifolia × F. japonica) × F. hindsii), `Sinton' citrangequat [(C. sinensis × Poncirus trifoliata) × unknown kumquat], `Mr John's Longevity' citrangequat [(C. sinensis × P. trifoliata) × F. obovat], razzlequat (Eremocitrus glauca × unknown kumquat), and `Nippon' orangequat (C. unshiu × F. crassifolia) survived freezing, but all experienced at least some defoliation and stem dieback. `Owari' satsuma (C. unshiu), `Changsha' mandarin (C. reticulata), nansho daidai (C. taiwanica) and ichang papeda (C. ichangensis) experienced only minor stem dieback but substantial defoliation in most years, except that ichang papeda was substantially damaged in the last year of the study. Seven cultivars produced fruit at least once during their first 4 years: nansho daidai, ichang papeda, `Nippon' orangequat, `Mr John's Longevity' citrangequat, `Owari' satsuma, `Changsha' mandarin, and procimequat. Based on cold hardiness, fruiting, and growth characteristics, `Owari' satsuma, `Changsha' mandarin, `Mr John's Longevity' citrangequat, and `Nippon' orangequat provided the hardiest, most precocious and desirable fruiting landscape trees in this study.
Mark Rieger, Gerard Krewer, Pam Lewis, Mindy Linton and Tom McClendon
George Boyhan, Reid Torrance, David Curry, Pam Lewis and Mindy Linton
In 1998–99, experiments were conducted to evaluate current fertility practices with plant-bed onions. In experiments in 1998 and 1999, a factorial experiment of preplant 5–10–15 and CaNO3 sidedressing indicated that CaNO3 had a significant effect on foliar nitrogen levels. CaNO3 also had an effect on stand count in 1998, but not in 1999. CaNO3 and 5–10–15 had an effect on plant height in both 1998 and 1999, with an interaction between 5–10–15 and CaNO3 in 1999. In 1999, transplants were also evaluated on an acceptability scale with 5–10–15 and CaNO3 rates resulting in significant differences in transplant acceptability. Postseedling applications of high phosphorus fertilizer were also evaluated. There were no consistent improvements in transplant growth with applications of high phosphorus fertilizers, such as 18–46–0 or 10–34–0, either on soils with very high residual phosphorus (242 lb/acre) or medium residual phosphorus (50 lb/acre). In addition, variety was not a factor in these responses.