Growth of leaf epidermis exhibits spatiotemporal variability.

Registration of 'TifEagle' Bermudagrass 'TifEagle' bermudagrass [Cynodon dactylon (L.) Pers x C. transvaalensis Burtt-Davy] (Reg. no. CV-38, PI 606545) was cooperatively released by the USDA-ARS and the University of Georgia Coastal Plain Experiment Station in August 1997. TifEagle is a high-quality turf bermudagrass cultivar for golf course greens and other applications requiring close mowing. TifEagle produces better quality turf than 'Tifdwarf when mowed daily at 4 mm or less. TifEagle was tested as TW-72. TifEagle was selected in 1990 as a dense, fine-textured, offlype genotype within a plot of an induced mutation (Mutant no. 2). Mutant no. 2 was one of 48 putative mutants induced in 'Tifway 2' with 70 Gy (7000 rads) of Cobalt-60 y-radiation in 1988. These 48 mutants were propagated in separate plots and mowed three times aweek at6 mm in 1989 and 1990. TifEagle is avegetatively propagated cultivar that was selected for its ability to produce highquality turf under close mowing (4 mm or less), lack of seedhead formation at Tifton, GA, and Auburn, AL, and lower levels of tawny mole cricket (Scapteriscus victims Scudder) infestation compared with Tifdwarf after the establishment year at Tifton and Savannah, GA.

Growth of the anticlinal and outer periclinal walls of leaf pavement cells is heterogeneous. The growth of the lobes resembles cell elongation via diffuse growth rather than tip growth.

A systematic method of defining the developmental stages of upland cotton (Gossypium hirsutum L.) is described. The stages of growth are divided into two groups: vegetative and reproductive. The stage of growth of an individual plant is determined by the number of main stem nodes. The uppermost node immediately preceded by a 1.25‐cm internode is considered the latest developed node for staging purposes.Use of these systematic growth stages should lead to more uniform application of agronomic research treatments, cultural practices, and the like.

Main conclusionSome interspecific hybrid bermudagrass cultivars used on golf course putting greens are genetically unstable, which has caused phenotypically different off-type grasses to occur in production nurseries and putting surfaces. Management practices to reduce the occurrence of off-type grasses in putting green surfaces and the effect they can have on putting quality and performance need to be researched until genetically stable cultivars are developed.Golf course putting green surfaces in subtropical and tropical climates are typically planted with an interspecific hybrid bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy), because of the superior putting quality and performance of these cultivars. ‘Tifgreen’ was one of the first interspecific hybrids developed for putting green use in lieu of common bermudagrass. However, off-type grasses began appearing in established Tifgreen stands soon after commercial release. Off-type grasses are those with different morphology and performance when compared to the surrounding, desirable cultivar. Off-types have the potential to decrease surface uniformity, which negatively affects putting surface quality. However, several unique off-types from Tifgreen have been selected as commercial cultivars, the first being ‘Tifdwarf’; then ‘Floradwarf’, ‘MS-Supreme’, ‘Pee Dee-102’, and ‘TL-2’, identified later. The cultivars ‘Champion Dwarf’, ‘P-18’, ‘RJT’, and ‘Emerald Dwarf’ were subsequently selected as off-types in Tifdwarf. The naturally occurring off-types and cultivars that have been identified within the Tifgreen family have widely differing phenotypes; however, they are reported to be genetically similar, supporting the hypothesis that their occurrence is a result of somatic mutations. Genetic instability in currently available commercial cultivars is likely to lead to the continued presence of off-types in production nurseries and putting greens. Additional research is needed to understand the nature of genetic instability in Tifgreen-derived cultivars and how to manage its consequences to develop new cultivars, but also strategies for eradication of off-types in pedigree nursery production and end-site putting greens.