Genome size variation in Pisum sativum

Abstract

Pisum sativum L. is one of the plant species where infraspecific genome size variation, up to 1.29-fold between cultivars, has been reported. The present investigation deals with a Feulgen cytophotometric analysis of this phenomenon in 25 wild accessions, landraces, and cultivars of widely different geographic origin. Differences between accessions were maximally 1.054-fold in single experiments but proved to be nonreproducible upon repeated measurements. Seedlings of the same accession often differed significantly, up to 1.056-fold, but values from root and shoot tips in one individual were not significantly correlated, indicating the absence of true genome size variation between plants. Upon calibration against Allium cepa a 1C value of 4.42 pg is estimated for Pisum sativum. Altogether the data suggest that, contrary to the divergence in the literature data and recent reports on DNA content variation, the pea has a stable genome size.

Genome size and maturity group in Glycine max (soybean)

“…(1994). One test was made with formaldehyde as fixative (see Greilhuber, 1986Greilhuber, , 1987and Greilhuber & Ebert, 1994 for the rationale). Again, no difference between the culti- vars was evident ( Table 2).…”

“…Feulgen densitometry followed Greilhuber & Ebert (1994); details are explained in Tables 1 and 2. Because of the low genome size in soybean, metaphases in side view were measured to obtain a reasonable amount of absorbance.…”

Estimating genome conservation between crop and model legume species

“…sativum is particularly striking given the 10 times larger genome (26) and one less chromosome in Pi. sativum.…”

Temperature responses and nuclear DNA amounts of seven white clover populations which differ in early spring growth rates

“…The density of stain of each white clover population was determined in 30 early-prophase nuclei (10 on each of three slides) at 560 nm, using a Vickers M85 scanning microdensitometer, with modifications to correct for errors from glare (Goldstein 1981). Determinations were made within 10 days of preparing the slides to prevent effects of ageing on the intensity and regularity of the Feulgen staining (Greilhuber & Ebert 1994). The repeatability of determinations was also checked (as recommended by Bennett & Leitch 1995) by making identical preparations for two of the populations at the University of Sheffield, UK and measuring nuclear DNA amounts there using a Vickers M85A scanning microdensitometer.…”

“…It was suggested that individuals of P. annua with larger DNA amounts would be expected to develop more rapidly under winter and early spring conditions, providing a temporary advantage sufficient to evade competition from the potentially faster growing individuals with lower DNA amounts. However, it should be noted that Greilhuber & Ebert (1994) and Bennett & Leitch 16 New Zealand Journal of Agricultural Research, 1999, Vol. 42 (1995 have recently questioned whether reports of such very large differences in genome size within species (of the order of 100% to 288%) may in part reflect inaccuracies in staining methodology.…”