Sweetpotato, Ipomoea batatas is in the morning glory family, Convolvulaceae, genus Ipomoea, group Batatas. It has many wild Ipomoea relatives that serve as a reservoir of many needed pest and stress-resistance genes. A major barrier to introgression of useful genes is the ploidy gap—sweetpotato is a hexaploid and wild Ipomoeas are diploids and tetraploids. The wild species can be successfully crossed using 2n pollen or by first increasing ploidy by colchicine treatment. The ploidy of such hybrid offpsring can be determined by DNA flow cytometry. My objective was to develop a technique to determine DNA content in Ipomoea and values for DNA content for the major Ipomoea species using the EPIC flow cytometer with a UV detector. Nuclei were extracted and pretreated with cellulase and pectolyase before staining with propidium iodide (PI). A highly linear relationship was found between the DNA content determined by DNA flow cytometry and the ploidy of the closest sweetpotato relatives as determined by chromosome counts. These species were diploid I. trifida, tetraploid I. batatas, and hexaploid I. batatas. DNA content was most similar among other diploid Ipomoea species in the group Batatas and was significantly different in other Ipomoeas not in group Batatas.
pollen and cytological traits. The objectives of this study are to characterize fully the chromosome and pollen morphology, pollen stainability, and nuclear DNA content of gulf vervain. Materials and Methods Plant materials. Gulf vervain
stainability on these porterweeds, which would be useful data in the breeding of noninvasive plants. Pollen staining has become a reliable method of determining pollen viability in hybridization studies ( Czarnecki et al., 2014 ). Other porterweed studies have
Salvias : Sages for every garden 2nd ed. Timber Press Portland, OR Coleman, A.W. Maguire, M.J. Coleman, J.R. 1981 Mithramycin- and 4'-6-diamidino-2-pheylindole (DAPI)-DNA staining for fluorescence microspectrophotometric measurement of DNA in
® ; Partec) and stained with either fluorochrome. For PI-stained samples, RNase was included to ensure staining of DNA exclusively. Cotoneaster samples were prepared using 4 cm of rapidly growing terminal stem tissue including vegetative buds and we used 1
estimations ( Doležel and Bartos, 2005 ; Doležel et al., 2007 ; Noirot et al., 2005 ). Likewise, some variations in nuclear DNA content between species are possibly artifacts caused by the inability of the dye to access DNA, since the fluorescent stains PI
using a 20-μm filter (Cell Trics; Partec, Münster, Germany) and stained with 25 μg·L −1 propidium iodide. The relative fluorescence of the total DNA was measured for each nucleus using a flow cytometry system (Cell Laboratory Quanta TM SC MPL System
must be established. Although the citrus chromosome number is relatively small (2 n = 18), karyotyping is difficult because metaphase chromosomes are very small and morphologically similar. Fluorochromes chromomycin A3 staining is useful for
misshaped, nonstained, or unevenly light-stained pollen grains were counted as nonstainable. For each variety, more than 600 pollen grains (if produced and available) were examined from four replicate samples. Nuclear DNA content and ploidy analysis. Over
, we examined their leaf morphology, stomata size and density, pollen stainability, chromosome number and nuclear DNA content, and SSR banding pattern. These findings will have major implications on caladium breeding, their possible origins, and