Pollen Germination of Rhizoma Peanut cv. Florigraze1

Abstract Assessing pollen germination is fundamental to investigating infertility in plants. A potential cause of poor seed production in Florigraze (Arachis glabrata Benth.), rhizomatous peanut, was investigated by incubating pollen on in vitro germination media. The optimum sucrose and boron concentrations for pollen germination was delineated in a series of factorial experiments. Pollen germinability was assessed four times during the growing season. Flowers were collected at 2 h intervals spanning 30 h of development from bud to wilted flower. The optimum sucrose concentration was 100 g kg-1 but there were no differences in germination for B concentrations between 50 and 1,000 mg kg-1. Up to 78% pollen germination was obtained in a solution consisting of 100 g kg-1 sucrose, 100 mg kg-1 H3BO3, 250 mg kg-1 Ca(NO3)2·4H2O, 200 mg kg-1 MgSO4·7H2O and 100 mg kg-1 KNO3 in deionized water. Repeatable estimates of germinability were obtained in incubations of less than 30 min at 35 C. Florigraze pollen collected from developing buds as early as 2200 h the night before anthesis germinated in vitro. Peak germination extended from 2400 h to 1200 h the morning of anthesis. Under cool, dry conditions, the pollen collected 2 d after anthesis remained germinable. These results suggested poor pollen germinability was not the basis of low seed production in rhizomatous peanut. Pollen with high in vitro germination can dependably be collected from Florigraze flowers throughout the growing season during the first 6 h following anthesis, usually between sunrise to noon.