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Mode of Reproduction in Cytotypes of Lehmann Lovegrass

Voigt, P. W., Burson, B. L., Sherman, R. A.
Crop science 1992 v.32 no.1 pp. 118-121
Eragrostis lehmanniana, biotypes, sexual reproduction, germplasm, chromosome number, diploidy, triploidy, tetraploidy, seed set, self-pollination, open pollination, cross pollination, apomixis
All known sources of lehmann lovegrass, Eragrostis lehmanniana Nees, reproduce by apomixis, which precludes hybridization and conventional genetic research. This study was conducted to locate sexual germplasm and describe the reproductive process in lehmann lovegrass. Purported diploid germplasm was grown in pots in a greenhouse. Chromosome number was determined and embryo sac development was studied and compared with another lehmann lovegrass accession. Self fertility, open-pollinated seed set, and mode of reproduction by progeny test were evaluated. Three accessions were diploid (2n = 2x = 20) and two were tetraploid (2n = 4x = 40). Triploid plants (2n = 3x = 30), discovered in the primarily diploid accessions, probably resulted either from the union of reduced and unreduced gametes or from fertilization of diploid plants by pollen from nearby tetraploid lehmann lovegrass. Diploid plants were sexual (i.e., megaspores were produced) and required cross pollination for seed set. Triploid and tetraploid plants were facultative diplosporous apomicts. Progeny tests were not conclusive. Although some diploid plants were clearly different from others, morphological differences were not sufficient to clearly and easily differentiate genetic from environmental variation. This is the first report of sexual reproduction in E. lehmanniana. This sexual germplasm will be essential to future genetic research with lehmann lovegrass.