Comparison of three pollination methods for Eucalyptus argophloia, a small-flowered eucalypt

Abstract

Abstract& Context Most studies assess pollination success at capsule maturity, and studies of pre-zygotic processes are often lacking. & Aims This study investigates the suitability of controlled pollination for a potential forestry plantation species, Eucalyptus argophloia, by examining pre-and post-zygotic pollination success. & Methods Pollen tube development, capsule set and seed set are compared following three-stop pollination, artificially induced protogyny (AIP), AIP unpollinated and open pollination. The fecundity of stored pollen was compared with that of fresh pollen. & Results Three-stop pollination, AIP and open pollination had similar numbers of pollen tubes, but AIP unpollinated had none. Open pollination produced significantly more capsules and total number of seeds than the other treatments. There were significantly more seeds per retained capsule for the open pollination and three-stop pollination treatments than for the AIP and AIP unpollinated pollination treatments. There were no significant differences relative to the age of pollen. & Conclusions Pre-zygotic success in terms of pollen tubes was similar for open-pollinated, three stop and AIP, but was not reflected in post-zygotic success when the open pollination and three-stop method produced significantly more seeds per retained capsule than the AIP treatments and open pollination yielded more seeds. Capsule set and total seed set for open pollination, and fewer capsules in controlled pollinations, may reflect physical damage to buds because of the small E. argophloia flowers. Suitable alternative breeding strategies other than controlled pollinations are discussed for this species.

Significance of stigma receptivity in intergeneric cross-pollination of Salix × Populus

“…Similar methods of SR evaluation have been reported in other plant species [35,36]. Short SR time appears to be characteristic of Salix species, together with the pattern of stigma structure, both expressing a high degree of similarity in four willow genotypes.…”

“…These observations reflect density dependence on the pollen germination rates which have been observed to increase simultaneously with increasing pollen density on the stigma. The "pollen population effect" is also associated with secretion of small peptides which can induce pollen germination and enhance possibility of fertilization [30,36].…”

“…Using a two-factor randomized design (four willow species × one poplar donor of pollen), pollen germination after four combinations of experimental design was evaluated. Following the Randall procedure of one-stop pollination [36], the mature pistils were hand-pollinated, when half of every willow catkin came into anthesis, i.e., at the "Salix growth stage 6.65" according to Saska and Kuzovkina [37]. As a control, the stigmas of Populus tremula treated by P. tremula pollen was evaluated.…”

Flowering acceleration in native Brazilian tree species for genetic conservation and breeding

“…Hybridization is one of the fastest and most efficient ways to enhance genetic gains in forest species (Dickinson et al 2010, Randall et al 2015. Many studies have been carried out with Eucalyptus (Assis et al 2005, Horsley et al 2010, Corymbia (Dickinson et al 2010), and Hevea brasiliensis (Hamzah et al 2002), resulting in increased productivity in forest-based industries (Assis & Mafia 2007).…”

Research Article Analysis of Mendelian inheritance and genetic linkage in microsatellite loci of Eucalyptus urophylla S.T. Blake.

“…SSR markers have been used extensively due to their codominant inheritance and high locus polymorphism (Grattapaglia et al, 2012;Randall et al, 2015). However, it is critical to confirm if SSR loci employed in population genetic analyses are in fact genetic markers.…”