Different storage temperatures and times on pollen quality in cut rose varieties

Abstract

Pollen parent is one of the most important factors affecting the seed set in conventional breeding. Pollen quality of pollen parents must be known for success in breeding programs. Breeders also must know how long pollen grains keep their viability to overcome geographical distance and the difference in blooming times among parents. This study was conducted to find out the viability, germination rate, and duration of the keeping viability of pollen of rose varieties being kept for 0, 4, 8, 16, 24 hours at 24 ºC and 0, 1, 2, 3, 4, 5 days at 4 ºC. The pollen of the Inferno, Layla, First Red, and Myrna varieties were used as plant material. The IKI and petri dishes methods were used to determine pollen quality. The results showed that the viable pollen rate of varieties varied between 41.1% and 49.9%, whereas the germination rate was 3.8% and 29.9% and morphological pollen rate was 71.8% and 88.7%. In all varieties, viability, germination rate and morphological normal pollen rate decreased over time both kept at 24 ºC and 4 ºC, but fresh pollen lost its quality faster than pollen stored. Fresh pollen viability rate decreased by 11.9% and 25.6% at the end of 24 hours, whereas only it decreased by 10.4%-22.6% on 1st day of storage. The reduction in germination ability in Layla, Inferno and Myrna was over 60.0% on the 5th day, while it was found less than 50.0% in First Red. The decrease in morphologically normal pollen ratio was found statistically significant in both temperature treatments, except for Layla. As it is clear, the pollen quality was significantly affected by variety, storage/holding time, and conditions. It’s recommended to use stored pollen in breeding programs. Although it varies according to the varieties, the rose pollen should be use by keeping at 4 ºC between 2-5 days.