|Hussey, M - TEXAS A&M UNIVERSITY|
Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2002
Publication Date: February 1, 2003
Citation: BURSON, B.L., HUSSEY, M.A. POLLEN FERTILITY AND SEED SET IN FLORIDA PASPALUM, PASPALUM FLORIDANUM MICHX. SOUTHERN BRANCH OF AMERICAN SOCIETY OF AGRONOMY ABSTRACTS. 2003. V. 30. ABSTRACT P. 27-28. Technical Abstract: Florida paspalum, Paspalum floridanum Michx., is a warm-season bunchgrass native to the southeastern United States. Livestock graze the grass but there also is interest in using it as a food source for wildlife, especially game birds, because of its large seed. Little is known about its reproductive biology or fertility. It is a complex polyploid with about 160 chromosomes and is meiotically irregular. Because the grass produces viable seed in spite of its high ploidy level and irregular meiotic behavior, apomixis would be expected to be its means of reproduction. However, preliminary embryological studies indicate that it reproduces sexually, but this is tentative. To learn more about the fertility of Florida paspalum, pollen stainability, pollen germination and tube growth, and seed set were determined for accessions collected in Arkansas, Louisiana, and Texas. Pollen grains were stained with I2-KI to estimate viability. Stainability ranged from 26 to 62% with a mean of 42% for 19 accessions. To obtain a more accurate measure of viability, pollen germination on the stigmas and tube growth through the pistil were observed using fluorescent microscopy. Germination ranged from 46 to 75% for the different accessions. Pollen grains germinated immediately upon contacting the stigmas and the tubes grew to the base of the ovule within 4 to 6 hours following pollination. Seed set ranged from 41.9 to 90.5% with a mean of 81% for 11 accessions. Freshly harvested seed were dormant and did not germinate. Findings from this study show that: 1) pollen viability in Florida paspalum is very high considering its high chromosome number and meiotic irregularities; 2) seed set is higher than that of most Paspalum species; and 3) seed set in some of the naturally occurring ecotypes may be high enough for the grass to be a food source for wildlife and game birds.