Overcoming pre-fertilization barriers in the wide cross between Chrysanthemum grandiflorum (Ramat.) Kitamura and C. nankingense (Nakai) Tzvel. by using special pollination techniques

Abstract

In our earlier study, pre-fertilization barrier was one of the main factors causing the failure of the wide hybridization between Chrysanthemum grandiflorum 'Yuhuaxingchen' and C. nankingense, and seriously restricted the utilization of the excellent chrysanthemum germplasm, C. nankingense. In order to overcome the pre-fertilization barrier and obtain some hybrids, we carried out wide hybridization between them again in this study, and tentatively adopted three pollination techniques including mentor pollen, delayed pollination, and gibberellic acid treatment. The average number of pollen grains germinating on stigma at 24 h after pollination and the percentage of embryo were investigated with a temporary mount method and the technique of fluorescence microscopy. It was found that, compared with the control, delayed pollination, gibberellic acid treatment, and mentor pollen significantly increased the average number of pollen grains germinating on each stigma at 24 h after pollination by approximately 152, 235, and 182%, respectively. In addition, all the three pollination techniques significantly increased the percentage of normal embryos at different periods after artificial pollination in comparison to the control. Furthermore, seed sets of the crosses using the three special pollination techniques were 1.1, 1.4, and 2.0%, respectively, whereas we did not obtained any seeds in the control. Taken together, these results suggest that delayed pollination, gibberellic acid treatment, and mentor pollen are three useful pollination techniques for overcoming pre-fertilization barriers and increasing seed set in the wide hybridization between C. grandiflorum 'Yuhuaxingchen' and C. nankingense, and they may be widely applied for increasing breeding efficiency in other chrysanthemum wide hybridization facing similar pre-fertilization barriers.

Interspecific cross‐hybrids of Nicotiana tabacum L. cv. (gla.) S ‘K326’ with Nicotiana alata

“…Therefore, delayed or repeated pollination is effective to overcome prezygotic cross-incompatibility in these crosses. These pollination methods have also been reported to be useful in overcoming prefertilization incompatibility in Chrysanthemum grandiflorum and Solanum lycopersicon (Zhang 2009, Sun et al 2011, Yan et al 2009). It could be concluded that there was no difference of cross-compatibility before fertilization no matter whether the male fertile or CMS line was hybridized as the maternal parent.…”

“…However, hybrids always fail to be created because of cross-incompatibility, leading to the potentially usable germplasm in Nicotiana remained largely unexploited (Laskowska and Berbec 2005). Numerous efforts have been made to increase interspecific cross-compatibility, such as bud-stage pollination, delayed pollination, repeated pollination, mentor pollination and bridge cross (VanTuyl et al 1988, Somta et al 2006, Sun et al 2011, which have been effective in improving cross-compatibility in many plants.…”

The Usage of Genomic Selection Strategy in Plant Breeding

“…Additionally advances in high-throughput genotyping have markedly reduced the value per data point of molecular markers and increasing genome coverage. This reduction was in the main the results of three parallel developments [2] (i) the invention of huge numbers of single nucleotide polymorphism (SNP) markers in several species; (ii) development of high-throughput technologies, like multiplexing and gel-free deoxyribonucleic acid arrays, for screening SNP polymorphisms; and (iii) automation of the marker-genotyping method, together with efficient procedures for deoxyribonucleic acid extraction [2]. Phenotyping prices are increased Genotyping prices are being reduced and marker densities are being increased speedily.…”

“…The prediction accuracy of the GEBVs is evaluated by the correlation between the GEBVs and empirically estimated breeding values, r(GEBV: EBV), where the EBV can be obtained in a number of ways, most simply, as a phenotypic mean. This correlation provides an estimate of selection accuracy and thus directly relates GEBV prediction accuracy to selection response [2]. Other statistics such as mean-square error (MSE) are used occasionally [3].…”

“…The correction, r(EBV:TBV), accounts for the fact that the EBV in the validation set is not free of error. When the EBVs are phenotypes, r(EBV:TBV) is equal to the square root of heritability (h) within the validation set [2].…”