Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Plant, Environmental Management and Soil Sciences

First Advisor

Freddie A. Martin


The effects of daylength decline rates and relative humidity levels and durations on pollen viability and seed setting of sugarcane (Saccharum spp.) were investigated. Two studies were carried out at St. Gabriel Research Station of the Louisiana Agricultural Experiment Station. Daylength decline rates of one half and one minute per day were studied on 354 crosses made within three years using 54 males and 92 females. Males treated with one half minute daylength decline rate had higher pollen viability. Seed production was not affected by the treatments. Varietal differences were found responsible for most of the variation obtained. The two rates investigated in this study can be used in the breeding program without negative effects on seed production from the crosses. Three relative humidity levels (90%, 70%, and an ambient treatment) and three relative humidity durations during crossing (day, night, and an ambient treatment) were investigated in two experiments for their effects on pollen grain viability and seed setting of sugarcane during three seasons. Pollen viability and seed production were not affected by altering humidity level or duration. Setting the relative humidity at within a range of 65 to 81% will not adversely affect pollen viability or seed production in sugarcane crosses.