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Abstract
A clear understanding of the reproductive biology of seashore paspalum (Paspalum vaginatum Sw.) is needed to design improved production systems for seeded cultivars. A series of studies were conducted to determine the impact of environmental parameters on floral initiation; evaluate pollen release patterns, pollen viability, and longevity; as well as to determine of sexual compatibility levels among genotypes of seashore paspalum. The primary result of flowering habit studies of the seashore paspalum germplasm collection indicated that in general, in Griffin, GA, flower initiation increases while the day length approaches the longest day of the year. Flowering response to solar radiation showed significant reductions in flowering when radiation levels were reduced to 41% or less of the unshaded control. Seashore paspalum pollen was released between 0700 h and 1100 h with a very sharp release peak around 0800 h. The quantity of pollen released during this period was positively related to the solar radiation at 0800 h. An optimized liquid germination medium was developed to effectively evaluate pollen viability and longevity for seashore paspalum. Pollen collected at 0730 h from seven genotypes of seashore paspalum had viabilities that ranged from 60 to 88%. Pollen longevity of plant material from greenhouse and field environments was 80 min and 100 min, respectively at room temperature. Pollen longevity was negatively impacted by temperatures of 30C or more. Studies of pollen-stigma interactions indicated that seashore paspalum is a self-incompatible and cross-fertile species. Results from a six by six reciprocal crossing experiment indicated that all cross pollinations produced seeds but varied in percent seed set from 7.7 to 66.3 %. Seed germination rates of seed produced in this crossing experiment ranged from 56.7% to 98.1% and 47% of all hybrid seeds had greater than 90% germination. The findings of this research provide useful information for future seashore paspalum breeding programs.