Somatic hybrids between Gossypium hirsutum L. (4×) and G. davidsonii Kellog (2×) produced by protoplast fusion

Abstract

Somatic hybrids were obtained from electrofused protoplasts derived from embryogenic suspension cultures of tetraploid cotton (G. hirsutum L. cv. Coker 201) and embryogenic callus of diploid wild cotton G. davidsonii. The regenerants were initially identified as hybrids by RAPD (random amplified polymorphic DNA) analysis. Subsequently, observation on chromosome counting, morphology and SSR (simple sequence repeat) confirmed the hybrid status. Cytological investigation of the metaphase root-tip cells of the regenerated plants revealed there were 74 to 84 chromosomes in the plants, close to the expected 78 chromosomes. SSR analysis revealed the regenerated plants contained specific genomic fragments from both fusion partners, further confirmed their hybridity. The morphology of the plants was intermediate between the two fusion partners. The regenerants were difficult to develop into mature plants because their roots browned and they wilted from the stem apex before forming 3 to 5 true leaves. The hybrid plants were transferred to soil by grafting in vitro onto rootstocks.

Production and characterization of asymmetric hybrids between upland cotton Coker 201 (Gossypium hirsutum) and wild cotton (G. klozschianum Anderss)

“…To our knowledge, this is the first report about production of asymmetric somatic hybrids in cotton, and this progress might be a useful tool for producing novel germplasm for breeding programs. Protoplast culture in upland cotton and wild species and symmetric protoplast fusion in cotton had been achieved successfully and reported in detail in our laboratory (Sun et al 2004(Sun et al , 2005(Sun et al , 2006. Until now, we have done experiments on protoplast culture and protoplast fusion, but the advantages or limitations of asymmetric and symmetric somatic hybrids in breeding programs have not yet been systematically investigated and require more information for further analysis.…”

“…But the unit yield increase has been limited by numerous diseases and pests that cause serious yield reduction. The transfer of polygenic traits such as pathogen resistance is of great importance in cotton (Kumria et al 2003;Sun et al 2004Sun et al , 2006. However, conventional breeding using sexual crossing is often restricted due to sexual incompatibility, especially if the gene of interest is only present in the wild species (Liang 1999).…”

“…An available way to bypass sexual-crossing barriers is via protoplast fusion through which we can transfer desirable agronomical relevant traits from wild cotton to cultivars. Symmetric protoplast fusion between wild and cultivated species has been achieved successfully in cotton (Sun et al 2004(Sun et al , 2005(Sun et al , 2006. However, besides desirable traits, some undesirable traits linked to fertility or yield in wild species were also present.…”

Selection of Gossypium hirsutum genotypes for interspecific introgression from G. arboreum using ovule culture

“…Techniques such as exogenous hormone application E-mail: John. Author(s) agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License (Altman, 1988), hexaploid bridging lines (Sacks and Robinson, 2009), in vitro interspecific fertilization (Liu et al, 1992), protoplast fusion (Sun et al, 2006), and ovule culture/embryo rescue (Stewart and Hsu, 1978;Gill and Bajaj, 1987) have been used for interspecific hybrid development in cotton. Ovule culture has frequently been used for hybrid development between incompatible diploid species and for crosses between diploid and tetraploid cotton species (Mehetre and Aher, 2004).…”

Unbiased genomic distribution of genes related to cell morphogenesis in cotton by chromosome mapping

“…Protoplast fusion can create new species, overcome hybridization incompatibility, and transfer organelles. Several successful examples of protoplast fusion between cotton species have been reported (Sun et al 2004(Sun et al , 2005(Sun et al , 2006aYang et al 2007b;Fu et al 2009;Sun et al 2011).…”