Karyological Studies in Grain Amaranthus

E.J. GREIZERSTEIN AND LIDIA POGGIO

CYTOLOGIA

UNIV TOKYO CYTOLOGIA

Año: 1994 vol. 59 p. 25 - 30

0011-4545

Amaranthus were an important pre-Columbian cultivation whieh have recently received increased attention due to their nutritional qualities, high lisine content, wide adaptability to different ecological niches and drought tolerance. Besides, they are C4 plants and photosynthe-tically efficient (Sauer 1967). Grain species of Amaranthus are not only richer in protein content than other cereals but also their properties for human diet are closer to the nutritional perfection (Gupta and Gudu 1991). In our laboratory a cytogenetic program in Amaranthus was devised in order to improve the karyological characterization of the species and cultivars, increase the knowledge of genetic resources and explore evolutionary trends. Several authors have demonstrated the existence of reproductive barriers to the cross among Amaranthus species and have suggested that there are genic or chromosomal differences that lead to the sterility of hybrids (Pal and Khoshoo 1973a, b, Greizerstein and Poggio 1992). Two gametic numbers have been reported in the genus (n 16, n 17) and in some cases both numbers occur in the same species. Pal et al. (1982) suggested that the gametic number n 17 originated from the n —16 through primary trisomy. Greizerstein and Poggio (1992), on the basis of the citogenetic analysis of interspecific hybrids support this hypothesis, and proposed that the species with 2n -32 are polyploids (basic number x 8) and that x1 16 is a derived basic number. The basic number x2= 17 would have appeared later by primary trisomy. In the present contribution we report the karyotype formulae and total DNA content of four species of Amaranthus namely A. caudatus L., A. cruentus L., A. hypochondriacus L. and A. mantegazzianus Passer with the aim of increasing the knowledge of this important cereal-like grain crop.