IDENTIFICATION OF A NEW CYTOTYPE OF PENNISETUM SQUAMULATUM FRESEN WITH 2N=56 CHROMOSOMES

摘要

Pennisetum L. Rich. is a tropical and subtropical genus of the tribe Paniceae consisting of more than 140 species (Jauhar 1961). Pennisetum glaucum (pearl millet) is the most important species of the genus as it ranks sixth amongst important cereals and is utilized as food, feed and fodder. Several species could contribute to the enrichment of the gene pool of cultivated pearl millet and serve as potential donors of desirable heritable traits (Hanna et al., 1989). Among such potential species for pearl millet improvement, P. squamulatum Fresen is highly important as it contains genes for perenniality, apomixis, and tolerance to many abiotic and biotic stresses (Hanna et at., 1989) Although incompatibility barriers have been known to operate betweenthe two species (Dujardin and Hanna, 1989; Kaushal and Sidhu, 2000), this species has been used widely to transfer some of the desirable characters to cultivated gene pool of pearl millet utilizing its induced tetraploid forms (Dujardin and Hanna, 1983;Dujardin and Hanna, 1989; Marchais and Tostain, 1997). Considerable success has been reported in transfer of apomixis to pearl millet utilizing P. squamuiatum as donor species (Ozias-Akins et al., 1998; Roche et al., 2002). Previous reports on cytological studies as well as in hybridization studies have designated P. squamuiatum as a hexaploid species with 2n=6x=54 chromosomes (Raman et al., 1959; Patil et al., 1961; Krishnaswami and Thulasidas, 1962; Sisodia, 1970; Rangaswamy, 1972; Dujardin and Hanna, 1989; Busri et al., 1992; Marchais and Tostain, 1997).