The ability to store rose pollen allows for greater flexibility when crossing asynchronously flowering parents. However, storage conditions and duration may lead to gametophytic selection and affect the resulting sporophytic populations. The objective of this study was to compare degradation of rose pollen stored for relatively short (two weeks) and long durations (52 weeks) at -80°C, -20°C, and 4 or 7.5°C. Results will be directed towards the longer-term objective of determining if gameto- phytic selection for cold tolerance is occurring by comparing sporophytic populations for cold hardiness. Rose selection 1B30 was chosen as the male because it is a cross of non-winter hardy × hardy (USDA cold hardiness zone 4) parents and should contain genes segregating for cold hardiness. Pollen was air dried, sealed in canisters, and placed at the designated temperatures. A hanging drop pollen germination assay (l.5% sucrose, 40ppm boric acid) was used to determine percent pollen germination (%PG) (after four hours) and pollen tube length (PTL) (after two hours). Over the 52- and two-week storage periods, seven and two pollen germination readings were made, respectively. On June 29, 2004, 52 and two weeks after storage treatments commenced, PTL and %PG data were taken and 24 pollinations per treatment (including a fresh pollen control) were made onto Rosa × 'Bucbi' (Carefree Beautytm ). Pollen germination quickly declined at 4 or 7.5°C, and after two and 52 weeks of storage %PG, PTL, and achene number per hip were generally greater at -80°C than -20°C. Achene number per hip was significantly correlated with PTL (r=0.86), but not with %PG, nor was %PG significantly correlated with PTL. Pollen tube length appeared to be predictive of fertilization ability and can be used to select pollen lots to maximize seed set and monitor treatment effects on pollen for pollen competition studies.
|Original language||English (US)|
|Number of pages||8|
|State||Published - Dec 1 2007|
- Pollen competition
- Pollen germination
- Pollen tube length