, Europe, Japan, Australia, and New Zealand ( Thorogood, 2003 ). In the United States, turf-type perennial ryegrasses are commonly used for golf courses, sports fields, lawns, and landscapes. Perennial ryegrass is naturally diploid; however, tetraploids
unbalanced chromosome segregation during meiosis. Therefore, the seedless triploid loquat has long been a research target of loquat breeders because of its higher rate of edible fruit compared with the diploid loquat with large seeds. During 1997 to 2006, we
). Artificial polyploid rhododendrons have also been developed to increase ornamental characteristics such as flower size and texture, extend time of flowering, produce more compact plants, and facilitate crosses not possible at the diploid level ( Eiselein
and pastures ( Hirata et al., 2007 ). Reproductive biology of M. sinensis has been studied in both wild populations and cultivars of diploid plants. Stewart et al. (2009) documented seed set (percentage of florets setting seed) among wild
provided by tetraploid parents combines with a gamete containing one set of chromosomes provided by diploid pollen and forms a triploid zygote ( Acquaah, 2007 ). After identification of ploidy levels from induction treatments, diploid, triploid, and
Seedless watermelons account for 78% of the watermelons sold in the United States ( U.S. Department of Agriculture, 2006 ). Triploid watermelon plants do not produce sufficient viable pollen to pollenize themselves and a diploid cultivar must be
, 1951 ); and in 2005, three-fourths of the United States' watermelon production was devoted to triploid cultivars ( USDA, Economic Research Service, 2005 ). In triploid watermelon production, diploids are included as a viable pollen source for
have been reported in diploid hybrid clones of Solanum phureja–Solanum stenotomum ( Lu et al., 2001 ) and greater than 2000 μg/100 g FW have been reported in other Solanum species germplasm ( Andre et al., 2007 ; Brown et al., 2006 ). Genotype
var. fragaria in strawberry. For resistance to Phytophthora root rot caused by Phytophthora fragaria var. rubi in the closely related diploid red raspberry ( Rubus ideaus ), a two-gene model with dominance has been suggested ( Pattison et al
impact worldwide. Rose has four subgenera, more than 100 species (diploid through decaploid) and more than 30,000 commercial cultivars (mostly diploid, triploid, and tetraploid). These cultivars exhibit wide interspecific and intraspecific cross