Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: C.L. Haynes x
Clear All Modify Search
Free access

C.L. Haynes, M.A. Dirr and R. Severson

The cold hardiness of Magnolia grandiflora `Claudia Wannamaker' and `Little Gem' was determined under 8, 12 and 16 hour daylengths. Temperature was maintained at 25C day and 20C night. In addition, specific and total carbohydrates of both cultivars were analyzed. Cold hardiness and carbohydrate content were tested at the beginning (0 week), middle (5 week), and end (9 week) of the study. As expected, both southern magnolia cultivars were more cold hardy after 9 weeks at 8 hour daylengths with -9C cold hardiness estimates, as compared to 12 and 16 hour daylengths. The 12 and 16 hour daylengths resulted in similar cold hardiness estimates of -6C after 9 weeks. Additional cold hardiness and carbohydrate information will be presented.

Free access

C.L. Haynes, O. M. Lindstrom and M. A. Dirr

The effects of timing of pruning in relation to cold hardiness of X Cupressocyparis leylandii (A. B. Jacks. and Dallim.) Dallim. and A. B. Jacks. `Haggerston Grey' and Lagerstroemia L. `Natchez' were evaluated on 6 test dates from August 1989 to March 1990. Pruning treatments decreased the cold hardiness of both taxa compared to unpruned controls on 5 test dates. Cold tolerance of `Haggerston Grey' decreased for 4 to 5 months following the August and October pruning compared to the unpruned controls. `Haggerston Grey's cold tolerance were reduced by 6C in February. October and December pruning of `Natchez' reduced cold hardiness by 4C in January. However, cold hardiness of January and February pruning treatments was similar to unpruned controls. In general, the data indicated that plants of `Haggerston Grey' pruned in October through February were less cold hardy than plants pruned in August. Ideally, `Natchez' crape myrtle should be pruned in late winter.

Free access

C.L. Haynes, O.M. Lindstrom and M.A. Dirr

Cooling treatments of 2, 4, and 6C/hour or warming at 25, 4, or 0C influenced the cold hardiness estimates of x Cupressocyparis leylandii (A.B. Jacks. and Dallim.) Dallim. and A.B. Jacks. (Leyland cypress), Lagerstroemia indica L. (crape myrtle), and Photinia ×fraseri Dress `Birmingham' (redtip photinia) at four times during the year. New growth from all taxa, especially spring growth, was injured or killed at higher temperatures by the fastest cooling rate and/or by warming at 25C. Cold hardiness of Leyland cypress was unaffected by the cooling and warming treatments. Crape myrtle had a significantly higher lowest survival temperature (LST) when warmed at 25C than at 4 or 0C. Photinia leaves and stems cooled at 6C/hour or warmed at 25C generally resulted in a higher LST than those cooled more slowly or warmed at lower temperatures. Cooling rates of 14C/hour and warming at 0 to 4C should be used in freeze tests with Leyland cypress and crape myrtle. For leaves and stems of photinia, 2C/hour cooling and warming at 0 to 4C should be used.

Free access

Randy C. Ploetz, Jody L. Haynes, Aimé Vázquez and David Benscher

In 1995, 37 new dessert and cooking bananas (Musa spp.) were introduced into South Florida for evaluation under local edaphic and environmental conditions. The number of pseudostems per mat, height at fruiting, and cycling time were determined during the first fruiting cycle, and bunch number and bunch weight were recorded from 1996 to 1998. A productivity index (PIX), calculated as 100 × mean bunch weight in kg/cycling time in days, was used to determine the productivity of the clones over time. Informal taste panels assessed the appearance and organoleptic qualities of fruit on a subjective 1 to 4 scale. In a separate experiment, the susceptibility of 30 of the clones to fusarium wilt, caused by Fusarium oxysporum f. sp. cubense, was assessed. Some of the most popular and productive clones were susceptible to fusarium wilt and are not recommended for production in areas that have a history of this disease. The dessert clones `Pisang Ceylan', FHIA01', FHIA02', and FHIA17' and the cooking accessions `Kandrian', `Kumunamba', and `Saba' resisted fusarium wilt, produced moderate to high yields (PIXs ≥ 1) of good to excellent fruit (mean ratings ≥ 3), and are recommended for use in all areas in Florida.

Free access

C.L. Haynes, O.M. Lindstrom and M.A. Dirr

Decreasing photoperiods and decreasing temperatures induce cold acclimation and the accumulation of soluble sugars in many plants. Two cultivars of southern magnolia differing in cold hardiness and acclimation patterns, were monitored to determine photoperiod × temperature interaction on cold hardiness and soluble sugar content. Cold hardiness increased with low temperatures and short photoperiods. Total soluble sugars, sucrose, and raffinose consistently increased in the leaves and stems of both cultivars in response primarily to low temperature. `Little Gem' was less responsive to photoperiod than `Claudia Wannamaker'

Free access

C.L. Haynes, O. M. Lindstrom and M. A. Dirr

The effects of timing of pruning in relation to cold hardiness of X Cupressocyparis leylandii (A. B. Jacks. and Dallim.) Dallim. and A. B. Jacks. `Haggerston Grey' and Lagerstroemia L. `Natchez' were evaluated on 6 test dates from August 1989 to March 1990. Pruning treatments decreased the cold hardiness of both taxa compared to unpruned controls on 5 test dates. Cold tolerance of `Haggerston Grey' decreased for 4 to 5 months following the August and October pruning compared to the unpruned controls. `Haggerston Grey's cold tolerance were reduced by 6C in February. October and December pruning of `Natchez' reduced cold hardiness by 4C in January. However, cold hardiness of January and February pruning treatments was similar to unpruned controls. In general, the data indicated that plants of `Haggerston Grey' pruned in October through February were less cold hardy than plants pruned in August. Ideally, `Natchez' crape myrtle should be pruned in late winter.

Free access

C. L. Haynes, O. M. Lindstrom, M. A. Dirr and R. Severson

Cold hardiness and carbohydrate content of 4 cultivars of field-grown southern magnolia (Magnolia grandiflora L.) were determined monthly during the 1992-1993 winter. Initially, `Claudia Wannamaker', `Little Gem', `Timeless Beauty', and `Victoria' had similar stem and leaf cold hardiness estimates of -6C in October. However, by February `Claudia Wannamaker' and `Victoria' stems were 6 and 3C more cold hardy than `Little Gem' and `Timeless Beauty' stems. `Claudia Wannamaker' leaves were also 6C more cold hardy than `Little Gem' and `Timeless Beauty' leaves in February. Carbohydrate analysis indicates increases in oligosaccharides during cold acclimation in fall.