CYTOLOGY AND REPRODUCTIVE CHARACTERISTICS IN PENNISETUM SETACEUM

Abstract

A green ecotype of fountaingrass, Pennisetum setaceum (Forsk.) Chiov., was found to be triploid (3 x = 27) with 9 II + 9 I at metaphase I. Meiotic behavior of the bivalents was normal, but the univalents lagged and divided precociously at anaphase I. The univalent halves lagged at anaphase II and were distributed at random. Micronuclei were common, and stainable pollen was approximately 40%. The green type produced four progeny with 54 chromosomes. A purple strain of P. setaceum was found to be hexaploid (6 x = 54) with varying chromosomal associations. Meiotic behavior was highly irregular and stainable pollen was almost zero. Megasporogenesis was initiated in both types, but the megaspores degenerated and nucellar and integument cells developed into four‐nucleate, aposporous embryo sacs. Following self‐pollination, the green type set approximately 10% seed and the purple type set 0.05% seed. Purple fountaingrass set as high as 18% seed following the application of pollen from Pennisetum ciliare (L.) Link (4 x = 36), exemplifying a rare form of pseudogamy between two species. Improvement of P. setaceum through a standard breeding program appears unlikely.