To our knowledge, there has been no published technique to produce consistently high-quality slides of somatic chromosomes of roses (Rosa sp.). Therefore, various pretreatments, fixatives, digestions, stains, and maceration and squashing methods were tested to identify a procedure to produce clear, well-spread chromosomes from shoot tips. The best results were obtained after pretreatment in a mixture of 0.1% colchicine and 0.001 m 8-hydroxyquinoline for 4 h, and fixation in 2 acetone: 1 acetic acid (v/v) with 2% (w/v) polyvinylpyrrolidone. The darkest-stained chromosomes were obtained with carbol-fuchsin staining of air-dried cell suspensions that had been spread in 3 ethanol: 1 acetic acid (v/v).
-generation hybrids ( Kamemoto et al., 1999 ). Differences in ploidy are a challenge to the development of new hybrids, and differences in chromosome number may prevent zygote development after pollination ( Singh and Hymowitz, 1987 ). Chromosome doubling is often
show the same basic chromosome number ( x = 12), similar karyotype features, and a very large genome size ( Zonneveld et al., 2005 ). Karyotype characteristics for most Lilium species have been examined ( Stewart, 1947 ), and two large metacentric
-values Database ( Bennett and Leitch, 2005 ) currently contains data for 5150 species; however, no genome size estimates have been reported for Callicarpa . Chromosome number has been a useful tool for researchers investigating evolutionary relationships ( Guerra
, disagreements on chromosome numbers of Curcuma species still exists ( Table 1 ). Somatic chromosome numbers of 2 n = 40, 42, and 77 were documented for C. oligantha Trim. by Saensouk and Chantaranothai (2003) , Eksomtramage et al. (2002) , and Leong
introduction and hybridization, there is limited information regarding the genetic basis of their morphological variation. Sharma and Bal (1958) examined chromosome numbers in root-tip cells of 24 croton varieties collected from India and found that all the
, analysis of pollen fertility, and chromosome observation in these three intergeneric hybrids for evaluating the validity of intergeneric hybridization in the improvement programs of colchicaceous ornamentals. We demonstrated for the first time
potentially valuable genetic resources, especially for disease resistance. The wild Rosa species that have been reported are euploids with chromosome numbers ranging from 2 n = 2 x = 14 to 2 n = 10 x = 70 ( Crane and Byrne, 2003 ; Darlington and Wylie
; Garcia et al., 1999 ; Ruiz and Asins, 2003 ; Sankar and Moore, 2001 ). It is important to confirm the correlation of linkage group with each chromosome. For chromosome mapping, the identification of each chromosome and detailed karyotyping techniques
carried out on no more than 10% of Orchidaceae (orchids) species due to the relatively high diversity in chromosome numbers and comparatively small or even minute chromosome size ( Myo et al., 2011 ; Tanaka and Kamemoto, 1984 ). Their patterns of