Genetic Resources and Crop Evolution 44: 241–245, 1997. 241 c 1997 Kluwer Academic Publishers. Printed in the Netherlands. Seed protein electrophoresis of wild and cultivated species of Celosia (Amaranthaceae) P. Nath, D. Ohri, S.S. Jha & M. Pal National Botanical Research Institute, Lucknow-226001, India Received 6 May 1996; accepted 8 October 1996 Key words: Celosia, electrophoresis, cockscomb, seed storage proteins, species relationships Summary Total seed storage proteins of five species of Celosia (14 taxa) have been compared by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Relative similarities between the taxa were estimated by Jaccard’s similarity index and cluster analysis was performed to produce a UPGMA dendrogram which divides 14 taxa into two groups while C. trigyna holds an isolated position. One group includes 4x C. cristata and C. plumosa, wild 8x C. argentea and 12x C. whitei and the other separates four accessions of 4x C. argentea. This raises a doubt regarding 4x types of C. argentea being the direct progenitors of the cultivated types. Introduction The genus Celosia comprises nearly 56 species of annual herbs which are distributed in tropical and tem- perate regions of Asia, Africa and America (Anony- mous, 1952). Two tetraploid species C. cristata and C. plumosa are cultivated in India for their grotesque fasciated inflorescences, which were earlier thought to have orginated from the wild species C. argentea (Grant, 1954). However, only octoploid form of C. argentea was known earlier and it was not possible to derive the origin of tetraploid cultivated types from an octoploid wild ancestor (Grant, 1954). Later tetraploid form of C. argentea was discovered from central India and it was shown to be the probable ancestor of cul- tivated types by the study of various intra- and inter- ploidal crosses (Khoshoo & Pal, 1973). The nuclear DNA amounts in various taxa have also been shown to be directly proportional to the ploidy level. This fur- ther suggests that all the taxa studied belong to one polyploid complex (Nath et al., 1994). Seed protein electrophoresis is very useful in elucidating the origin of cultivated plants (Ladizinsky & Hymowitz, 1979; Sammour, 1989; Ahmed & Slinkard, 1992; Jha & Ohri, 1996). In the present work, therefore 14 taxa of Celosia ranging from 2x to 12x have been studied for the seed storage protein profiles to examine their relationships and the origin of the cultivated types. Materials and methods Details of the plant materials used in the present study are given in Table 1. Protein extraction was carried out by homogenising cotyledon meal in 0.1 M Tris-HC1 buffer (pH 7.5). Samples of supernatent obtained under centrifugation at 17,600 g at 4 C for 20 min were dilut- ed with sample buffer containing 0.0625 M Tris-HC1, pH 6.8, 2.5% SDS, 5% 2-mercaptoethanol and 10% glycerol and heated in boiling water for 5 min prior to their being loaded on the gel. Total proteins in the samples were also estimated following the method of Lowry et al. (1951) so as to load equal quantities. Elec- trophoresis was carried out in the modified discontinu- ous sodium dodecyl sulphate PAGE(SDS-PAGE) sys- tem of Laemmli (1970) using 10% acrylamide resolv- ing gel (0.375 M Tris-HC1,pH 6.8). The running buffer was tris-glycine (9 g of Tris base, 43.2 g of glycine and 3 g of SDS in 3 litres of water, pH 8.3). Staining of the gels was done in 0.02% Coomassie Brilliant Blue R-250 containing 55% methanol and 7% acetic acid, while destaining was done in the same solution but without the dye. The Rf value for each band was com-