PHOTOPERIOD AND POLLEN STERILITY IN MAIZE

In comparison with long-day-grown controls, plants of the cultivar Golden Bantam of Zea mays L. grown in 8-h days show (a) acceleration of tassel and silk emergence, (b) reduced leaf number on the principal axis, (c) fewer tassel branches, (d) smaller total number of alicoles in the tassel, (e) greatly reduced pollen fertility, and (f) a tendency to sex reversal in the tassel. All of these effects are negated or reduced by night interruption by light at low intensity levels, and are therefore to be considered direct or indirect effects of true photoperiodic reactions and not consequences of reduced assimilate levels. Competition for assimilates could, however, play some part in determining the balance of male and female fertility, and some possible interpretations are discussed. Descriptions are given of cytological aberrations in anthers showing photoperiodically induced sterility. Most failures were found to occur in the late pre-meiotic period and the meiotic prophase, and visually detectable tapetal malfunction was apparent in the bulk of cases. © 1968 OXFORD UNIVERSITY PRESS.