Articles
IN VITRO BREEDING PROVIDES NEW AND UNIQUE OPPORTUNITIES FOR CONVENTIONAL BREEDING
Article number
829_8
Pages
65 – 72
Language
English
Abstract
The application of protoplast fusion technology in citrus improvement has resulted in the regeneration of somatic hybrid plants from more than 500 parental combinations.
In rare cases, a new somatic hybrid may have direct utility as an improved cultivar; however, the most important application of somatic hybridization is the building of novel germplasm as a source of elite breeding parents for various types of conventional crosses.
This is especially true in citrus, where somatic hybridization is generating superior allotetraploid breeding parents for use in interploid crosses to generate seedless triploids.
Seedlessness is a key breeding objective for new fresh fruit citrus varieties, and hundreds of triploid hybrids have been produced using somatic hybrids as the tetraploid parent.
Successful somatic hybridization in citrus rootstock improvement has allowed for the creation of a rootstock breeding program at the tetraploid level that achieves maximum genetic diversity in zygotic progeny and has great potential for tree size control via polyploidy.
Tree size control has gained importance as a means of reducing harvesting costs, maximizing the efficiency of modern cold protection methodology, and facilitating the adaptation of new fruit production systems.
Rootstock breeding at the tetraploid level facilitates the packaging of the many required traits for an improved rootstock into individual hybrids, including disease and insect resistance, wide adaptation, and ability to consistently produce high yields of quality fruit.
Recent progress and successful examples of these applications will be discussed.
In rare cases, a new somatic hybrid may have direct utility as an improved cultivar; however, the most important application of somatic hybridization is the building of novel germplasm as a source of elite breeding parents for various types of conventional crosses.
This is especially true in citrus, where somatic hybridization is generating superior allotetraploid breeding parents for use in interploid crosses to generate seedless triploids.
Seedlessness is a key breeding objective for new fresh fruit citrus varieties, and hundreds of triploid hybrids have been produced using somatic hybrids as the tetraploid parent.
Successful somatic hybridization in citrus rootstock improvement has allowed for the creation of a rootstock breeding program at the tetraploid level that achieves maximum genetic diversity in zygotic progeny and has great potential for tree size control via polyploidy.
Tree size control has gained importance as a means of reducing harvesting costs, maximizing the efficiency of modern cold protection methodology, and facilitating the adaptation of new fruit production systems.
Rootstock breeding at the tetraploid level facilitates the packaging of the many required traits for an improved rootstock into individual hybrids, including disease and insect resistance, wide adaptation, and ability to consistently produce high yields of quality fruit.
Recent progress and successful examples of these applications will be discussed.
Authors
J.W. Grosser, F.G. Gmitter Jr.
Keywords
citrus, disease resistance, rootstock, scion, seedless fruit, somatic hybridization
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