Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/10/1997
Publication Date: N/A
Citation: Interpretive Summary: Lotus corniculatus L. (broadleafed birdsfoot trefoil) is a forage legume grown in the United States, Canada, South America and Europe. Stand persistence depends on natural reseeding and individual plant persistence. Wild plants of L. corniculatus from Morocco are unique in that they produce rhizomes (stems that spread underground) which may prove useful in increasing the life of cultivated plants. Lotus corniculatus must be pollinated by bees to produce seed. Incorporating rhizomes into a self-pollinating plant should result in more consistent seed production. Recently, a self-pollinating plant of L. corniculatus was developed into an experimental breeding line called AG-S4. Objectives of this research were to cross progeny of AG-S4 with plants with rhizomes from Morocco and to determine if rhizome transfer was successful. Rhizomes were successfully expressed in F1 hybrids and a small number of hybrids were found to also be self-pollinating. Our observations suggest that rhizomes are inherited as a dominant trait. These hybrids, and subsequent generations, could lead to new self-pollinating cultivars of L. corniculatus capable of producing rhizomes. These self-pollinating hybrids are also important tools for determining how rhizomes are inherited.
Technical Abstract: Introduction of rhizomes from wild Lotus corniculatus L. germplasm from Morocco into domestic germplasm is considered an important step towards improving persistence of cultivated L. corniculatus, a cross-pollinated herbage crop. This study was initiated to determine if rhizomes could be transferred to a L. corniculatus germplasm that sexually reproduces via autogamy. Compatibility was high between the autogamous germplasm, AG-S4, and five wild accessions with rhizomes from Morocco. Higher crossing success was obtained when AG-S4 was used as a maternal parent. Most seeds produced were plump and had high germination. The resulting F1 progeny were morphologically intermediate between the parents, but tended to appear more similar to their Moroccan parents. Differences between reciprocal crosses were not evident. Hybridity of progeny was confirmed by random amplified polymorphic DNA analysis using eight primers. Fertility of F1's was low, relative to their parents. Meiosis of parental genotypes was characterized by a high frequency of bivalents, but the meiotic behavior of their F1 hybrids was more irregular. Frequency of univalents varied from 0 to 8 with an average 2.4 per cell indicating homology of chromosomes between AG-S4 and Moroccan accessions was not complete. Rhizomes were successfully expressed in F1 hybrids and a small number were found to also be autogamous. The autogamous hybrids are important tools to elucidate the inheritance of rhizomes in L. corniculatus. Selection among the hybrids could lead to autogamous cultivars of L. corniculatus with rhizomes.