Pollen Grain Preservation and Fertility in Valuable Commercial Rose Cultivars

Abstract

In the cut flower market, traditional breeding is still the best way to achieve new rose cultivars. The geographical delocalization of cultivar constitution (generally made in Europe and North America) and plant cultivation (large areas in Africa and South America) represents a limit point for crossing and selection. Rose breeders often need to overcome geographical distances, resulting in asynchrony in flowering among crossing parents, by storing and sending pollen. Hence, a key aspect in breeding programs is linked to pollen availability and conservation, jointly with the identification of parameters related to pollen fertility. In this study we present the results of three different trials. In the first, pollen diameter and pollen viability were chosen as fertility predictors of 10 Rosa hybrida commercial cultivars. In the second trial, aliquots of dried pollen grains of six R. hybrida cultivar were stored under two different temperatures (freezer at T = −20 °C and deep freezer at T = −80 °C) and after a wide range of conservation period, their viability was measured. In the third trial, the effective fertilization capacity of frozen pollen of 19 pollen donor cultivars was evaluated during 2015 crossing breeding plan, performing 44 hybridizations and correlating the number of seeds and the ratio seeds/crossing, obtained by each cultivar, with in vitro pollen germination ability.

Comparison of the Micromorphology and Ultrastructure of Pollen Grains of Selected Rubus idaeus L. Cultivars Grown in Commercial Plantation

“…The variation in the pollen grain size may result from the pollination and habitat conditions, whereas the pollen grain transport conditions have been found to play a negligible role in the evolution of the pollen size in species pollinated by bees and birds. The change in the grain size has been shown to influence pollen germination, pollen tube growth, and fertilization [ 107 , 108 ]. The pollen grain size may be modified by the content of nitrogen and phosphorus in the soil.…”

Viability of pollen grains and stigma receptivity in Desert Rose

“…The performance of pollen grains can be affected by different factors, extrinsic or intrinsic, in a variable way depending on the plant studied. Some studies have shown that environmental conditions during floral development can influence pollen grain fertility in different ways (Giovannini et al, 2017;Müller et al, 2016). Other studies have shown that factors related to the in vitro culture medium can affect pollen germination (Flores-Rentería et al, 2018;Impe et al, 2020).…”

Effects of Stored Pollens from Wild <i>Actinidia eriantha</i> Vines on Some Fruit Quality Traits

“…In the experiment on rose species; it was proven that cryostored pollen maintained its fertilization ability and produced seeds [19]. The study on frozen pollen stored among one year demonstrated that pollen stored at low temperatures sustained its original viability and fertility capacity so it was said that pollen storage is a useful tool for breeders [20]. Another research on Carica papaya L. "Washington" pollen which was freeze-dried and stored at −20˚C for 14 months showed that artificial pollination using stored pollen produced fruit set [21].…”