Inheritance of Photosensitivity in Maize1

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Abstract
Sensitivity of maturity in maize (Zea mays L.) to photoperiod restricts exchange of germplasm across latitude. To investigate the inheritance of this trait, the differences in photosensitivity between B68 and Tx61M (Exp. 1) and between C3 and Tx601 (Exp. 2) were investigated using total leaf number as a measure of maturity. In Exp. 1, the expected long‐day responses were not observed in two North Carolina environments. In a phytotron environment, both B68 and Tx61M exhibited significant photosensitivity; however, Tx61M, which averaged 7.6 more leaves under the longer photoperiod, was four times more sensitive than B68. In Exp. 2, evaluations were conducted in Florida (fall planting), North Carolina (spring planting), and under short‐day and long‐day photoperiods in a phytotron. Tx601 produced 4.4 more leaves in North Carolina than in Florida, and this was thought to be a photoperiodic response. An even greater photosensitivity was exhibited by Tx601 in the phytotron. A primary objective in Exp. 2 was to determine if photosensitivity in maize is simply inherited. An evaluation of the distribution of backcross‐derived lines was unsuccessful in resolving this issue. In both experiments a generation mean analysis indicated a preponderance of additive gene action.