Abstract
Wild tobacco species in the Nicotiana section Suaveolentes are promising genetic resources to introduce their disease resistance to cultivated tobacco, Nicotiana tabacum. However, hybrid lethality is observed in hybrid seedlings from crosses between most Suaveolentes species and N. tabacum. In particular, N. benthamiana belonging to the section Suaveolentes produces only viable hybrids after crossing with N. tabacum. In the present study, crossability between N. benthamiana and N. excelsior (section Suaveolentes) was investigated to test the possible usefulness of N. benthamiana as the bridge parent to transfer desirable genes of N. excelsior to N. tabacum via bridge crossing. After reciprocal crosses using three accessions of N. benthamiana and N. excelsior each, several crossing barriers such as cross-incompatibility, seed abortion, and male and female hybrid sterility were observed. Although reciprocal hybrids between N. benthamiana and N. excelsior showed a high degree of chromosome pairing in meiosis, univalents and multivalents, as well as chromosome bridges and lagging chromosomes, were observed. These meiotic abnormalities were thought to cause hybrid sterility. The possible usefulness of reciprocal hybrids between N. benthamiana and N. excelsior is discussed.
Highlights
We investigated the crossability between N. benthamiana and
The accessions obtained from the Leaf Tobacco Research Center (Japan Tobacco Inc., Oyama, Japan) were named JT to distinguish them from the United States Department of Agriculture (USDA) Plant Introduction (PI) accessions
JT in the present study indicate that several isolation barriers exist beCrossing results tween N. benthamiana and N. excelsior
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Regardless of whether it is naturally occurring or artificially performed, is an important evolutionary mechanism. Interspecific crosses may produce new species in nature, and several plant species are amphidiploids possessing two or more genomes that naturally arise from interspecific crosses and polyploidization [1,2,3]. Interspecific crosses are widely used for breeding purposes or genetic analysis [4,5,6]. Crossability between species depends on their genotypes, ploidy levels, and environmental factors
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