Submitted to: International Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 1996
Publication Date: N/A
Interpretive Summary: Weeping, boer, and lehmann lovegrasses were crossed with one another to determine how closely related these grasses are to one another. This information will be useful in determining which grasses can be used in a plant breeding program to transfer valuable traits from one grass to another in order to develop improved varieties. By microscopically examining the chromosome pairing behavior in the hybrids, it was possible to determine the relationship between the two species used as the parents of the resultant hybrid. It was determined that boer and weeping lovegrasses are very closely related and would be two grasses to use in a wide hybridization program for gene transfer. However, boer and lehmann lovegrasses are not as closely related and probably would not be as desirable species to use in a breeding program. Attempts to cross lehmann and weeping lovegrasses were not successful which suggests these two grasses may even be more distantly related than boer and lehmann. This information will be useful in determining which of these grasses should be used in a breeding program utilizing wide hybridization as a means of gene transfer.
Technical Abstract: Meiotic chromosome pairing behavior of hybrids between diploid and tetraploid cytotypes of weeping, boer and Lehmann lovegrasses was analyzed to better understand relationships within and between Eragrostis curvula and E. lehmanniana complexes. Within E. curvula complex, mean chromosome pairing behavior of diploid weeping x tetraploid weeping hybrid was 6.66I + 8.60II + 1.37III; diploid boer x diploid weeping hybrids was 0.36I + 9.82II; diploid boer x tetraploid weeping hybrids was 7.05I + 6.83II + 3.10III. Thus boer and weeping lovegrasses are closely related and have similar genomes. Boer lovegrass appears correctly classified as a botanical variety of E. curvula. Comparing the two complexes, tetraploid boer was crossed with diploid lehmann and a tetraploid cold-hardy lehmann type. Mean pairing behavior of tetraploid boer x diploid lehmann hybrids was 9.06I + 9.01II + 0.97III; tetraploid boer x CHL hybrids was 1.5I + 18.24II + 0.51IV. Lehmann and boer lovegrasses appear to have similar genomes and common ancestry. Members of the two complexes have the same genomic constitution and could be considered one complex. Reproduction method was determined for hybrids with an apomictic male parent. All were facultative apomicts with the type of apomixis being diplospory. There was evidence of aposporous development in some ovules of diploid boer x tetraploid weeping hybrid.