A comparative anatomical study in cassava diploid and tetraploid hybrids

Cassava, Manihot esculenta Crantz, is the most important crop for poor people in the tropics and subtropics. It is a woody plant scarcely studied from the anatomical viewpoint. Information on its anatomy is needed for use in plant breeding programs. An interspecific hybrid between cassava and M. oligantha Pax was obtained and artificially polyploidized by the second author. Hand cross sections were applied to the stem, colored by safranin and alcian blue, and mounted in synthetic resin. Tetraploid type showed a larger portion of medulla and absence of a growth ring. Vascular tissues in tetraploid were larger too. Both of these types had similar structure of vessel elements and articulated laticifers. Distribution of different tissues in the two types refers to more resistance to drought in the tetraploid type than in the diploid one.