Towards development of new ornamental plants: status and progress in wide hybridization

Abstract

The present review provides insights into the key findings of the hybridization process, crucial factors affecting the adaptation of new technologies within wide hybridization of ornamental plants and presents perspectives of further development of this strategy. Wide hybridization is one of the oldest breeding techniques that contributed enormously to the development of modern plant cultivars. Within ornamental breeding, it represents the main source of genetic variation. During the long history of wide hybridization, a number of methods were implemented allowing the evolution from a conventional breeding tool into a modern methodology. Nowadays, the research on model plants and crop species increases our understanding of reproductive isolation among distant species and partly explains the background of the traditional approaches previously used for overcoming hybridization barriers. Characterization of parental plants and hybrids is performed using molecular and cytological techniques that strongly facilitate breeding processes. Molecular markers and sequencing technologies are used for the assessment of genetic relationships among plants, as the genetic distance is typically depicted as one of the most important factors influencing cross-compatibility in hybridization processes. Furthermore, molecular marker systems are frequently applied for verification of hybrid state of the progeny. The flow cytometry and genomic in situ hybridization are used in the assessment of hybridization partners and characterization of hybrid progeny in relation to genome stabilization as well as genome recombination and introgression. In the future, new research and technologies are likely to provide more detailed information about genes and pathways responsible for interspecific reproductive isolation. Ultimately, this knowledge will enable development of strategies for obtaining compatible lines for hybrid production. Recent development in sequencing technologies and availability of sequence data will also facilitate creation of new molecular markers that will advance marker-assisted selection in hybridization process.

Genetic changes in a novel breeding population of Brassica napus synthesized from hundreds of crosses between B. rapa and B. carinata

“…Interspecific hybridization is a significant evolutionary process in crop speciation and a frequently used approach for crop genetic improvement (Abbott, 1992;Ellstrand and Schierenbeck, 2000;Hajjar and Hodgkin, 2007;Kuligowska et al, 2016;Mallet, 2005;Rieseberg and Carney, 1998). It is estimated that 25% of all plant species have undergone the process of interspecific hybridization in nature, and this process is thought to broaden genetic diversity and confer evolutionary advantages (Mallet, 2005).…”

“…During interspecific hybridization, rapid genomic alterations, such as transposon activation, transcriptional and epigenetic modification, and genomic structural variation which can result in potentially beneficial phenotypic variation, were attractive for crop germplasm innovation and thus frequently explored (Adams et al, 2004;Gaeta et al, 2007;Pires et al, 2004;Rieseberg and Ellstrand, 1993;Shaked et al, 2001;Shen et al, 2014;Singh et al, 2005;Soltis et al, 2016;Xiong et al, 2011;Zou et al, 2011). However, interspecific crosses often have strong hybridization barriers and require time-consuming selection following rapid segregation (Kuligowska et al, 2016;Lowry et al, 2008;Rieseberg and Carney, 1998). Often, offspring in early generations have poor fertility and genome stability (Cifuentes et al, 2010;Mason and Batley, 2015).…”

Yellow-Leaf 1 encodes a magnesium-protoporphyrin IX monomethyl ester cyclase, involved in chlorophyll biosynthesis in rice (Oryza sativa L.)

“…Some of these Chl-deficient mutants are seedling-specific and gradually become normal during later growth stages, and some can affect the plants for the entire life cycle. The yss1 rice mutant shows striated leaves at the seedling stage, particularly in leaf 3, but produces normal wild-type leaves later [38]. While, the vyl mutant develops decreased Chl levels throughout the whole developmental stages [39].…”

“…There are many reports of rice leaf color mutants, including v 1 , v 2 , wlp1 [40–42] and yss1 [38]. Most of them were used as morphological marker applied in roguing of hybrid rice seed production and parents seed multiplication.…”

Production and characterization of intersectional hybrids between <i>Tricyrtis</i> sect. <i>Brachycyrtis</i> and sect. <i>Hirtae</i> via ovule culture

“…Wide hybridization is one of the most effective approaches for broadening the variability in horticultural traits of ornamental plants (Küligowska et al 2016b). Although production of wide hybrids is often hindered by two types of hybridization barriers, i.e., pre-and postfertilization barriers, the latter can partly be overcome by embryo rescue such as embryo or ovule culture.…”