Pollen‐Mediated Gene Flow from Kentucky Bluegrass under Cultivated Field Conditions

Abstract

To direct, fund, promote and communicate horticultural research, which increases the quality and value of ornamental plants, improves the productivity and profitability of the nursery and landscape industry, and protects and enhances the environment.The use of any trade name in this article does not imply an endorsement of the equipment, product or process named, nor any criticism of any similar products that are not mentioned. AbstractGranier style thermal dissipation probes (TDPs) have been used to estimate whole plant water use on a variety of tree and vine species. However, studies using TDPs and load cells (gravimetric water loss) to estimate water use of landscape tree species are rare. This research compared gravimetric water loss (estimated with load cells) of four containerized landscape tree species with water loss estimated with TDPs. Over a 66 day period, an experiment compared water loss of three established, 5.0 cm (2 in) caliper poplar (Populus nigra 'Italica') trees in 75-liter (20 gal) containers on load cells to TDP estimated water loss. Each tree had a single 30 mm (1.2 inch) TDP inserted into the trunk at four heights above soil level (15, 30, 45, and 60 cm (6, 12, 18, and 24 in, respectively)). Data revealed TDP estimated water loss was less than load cell estimated water loss regardless of TDP height, but TDP estimated water loss at the 30 cm height was closest to actual load cell estimated tree water loss. Over the next three years, similar sized Bradford pear (Pyrus calleryana 'Bradford'), English oak (Quercus robur x Q. bicolor 'Asjes'), poplar (Populus deltoides 'Siouxland'), and sweetgum (Liquidambar styraciflua 'Rotundiloba') trees in containers were placed on load cells and one 30 mm TDP was placed into the trunk of each tree 30 cm above soil level. Over an extended time period, tree water loss was estimated using load cells and TDPs. Hourly TDP water loss estimates for each species over a three day period indicate TDP estimated water loss followed similar trends as load cell estimated water loss. However, TDP estimates were generally less than load cell estimates, especially during peak transpiration periods. For each species, mean total daily water loss estimates were less for TDP estimated water loss when compared to load cell estimated water loss. Although TDP estimated water loss has been correlated with actual tree water loss for many species, these data suggest errors may arise when using TDPs to estimate water loss of small, containerized landscape tree species.Index words: irrigation, container production, tree water use, poplar, Bradford pear, English oak, sweetgum. Species used in this study Significance to the Nursery IndustryBecause water quality and quantity are concerns in many regions of the United States, conserving water in nurseries and landscapes is essential. However, little research has been conducted into estimating tree water use in nurseries or landscape settings. We investigated methods to estimate water loss of four containerized landscape tree species ('...

Possible environmental risks at commercial growing transgenic forage crops

“…The average rate of gene transfer from transgenic tetra ploid and non transgenic apomictic tetraploid buck whest was 0.17% [83]. As follows from the practical results, if the complete protection against the spread of transgenes is not provided in the field, as a rule, the transfer of genes between apomictic species occurs at a relatively low frequency and short distances [17,83].…”

“…Twenty five sexual and fac ultative apomictic Poa species were used as pollen recipients and planted at a distance of 0, 13, and 53 m from transgenic plants. Total frequency of hybrid for mation was 0.048%, whereas the frequency of hybrid production at a distance of 0 m was 0.53% [17]. To determine the intensity of gene flow from apomictic tetraploid bahiagrass (Paspalum notatum Flugge) to tetraploid and diploid plants of the same culture of glu fosinate resistant apomictic buckwheat was grown at a distance of 0.5-3.5 m from non transgenic varieties.…”

Seed Yield, Development, and Variation in Diverse Poa pratensis Accessions

“…But for the cultivars Midnight and Belturf, we had expected a high degree of uniformity among plants; both were selected from single, highly apomictic plants (Meyer et al, 1984;Murray and Powell, 1976). Johnson et al (2006) reported that even though Midnight and Kenblue produced hybrids, it was at a frequency of <1%. Crosses of Belturf in the fi eld that produced nonmaternal plants were estimated at about 3%; yet it has been used as a parent for improved turf cultivars (Murray and Powell, 1976).…”

“…Crosses of Belturf in the fi eld that produced nonmaternal plants were estimated at about 3%; yet it has been used as a parent for improved turf cultivars (Murray and Powell, 1976). Johnson et al (2006) reported that even though Midnight and Kenblue produced hybrids, it was at a frequency of <1%. However, many recent cultivar releases of Kentucky bluegrass have taken advantage of the hybridization potential (Bashaw and Funk, 1987;Brede, 2006;Rose-Fricker et al, 2007).…”

Field Evaluation of Reduced‐Growth, Glyphosate‐Resistant Kentucky Bluegrass in a Noncompetitive Setting

“…Johnson et al (2006) have researched pollen‐mediated flow from transgenic Kentucky bluegrass to determine the environmental impact of the transformed grasses, and Blume et al (2008) have researched transgenic bluegrasses in a mown, competitive setting to assess vigor and competitiveness. The current study focuses on a field evaluation of transgenic Kentucky bluegrasses to evaluate potential ecological risks and agronomic performance in a nonmown, noncompetitive setting by comparing the vegetative growth and reproductive performance of the transgenic lines with nontransformed lines and reference cultivars.…”