Asymmetric somatic hybrid plants between Medicago sativa L. (alfalfa, lucerne) and Onobrychis viciifolia Scop. (sainfoin)

• Published in: Theoretical and applied genetics 1993-12, Vol.87 (4), p.455-463
• Main Authors: LI, Y.-G, TANNER, G. J, DELVES, A. C, LARKIN, P. J
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Classical genetics, quantitative genetics, hybrids; Fundamental and applied biological sciences. Psychology; fusion de protoplastes; fusion del protoplasto; Genetics of eukaryotes. Biological and molecular evolution; genomas; genome; genomes; hibridacion intergenerica; hibridacion somatica; hybridation intergenerique; hybridation somatique; intergeneric hybridization; Medicago sativa; Onobrychis viciifolia; protoplast fusion; Pteridophyta, spermatophyta; somatic hybridization; Vegetals
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/BF00215091

This paper reports on the production of intergeneric somatic hybrid plants between two sexually incompatible legume species. Medicago sativa (alfalfa, lucerne) leaf protoplasts were inactivated by lethal doses of iodoacetamide. Onobrychis viciifolia (sainfoin) suspension-cell protoplasts were gamma-irradiated at lethal doses. Following electrofusion under optimized conditions about 50,000 viable heterokaryons were produced in each test. The fusion prod- ucts were cultured with the help of alfalfa nurse protoplasts. Functional complementation permitted only the heterokaryons to survive. A total of 706 putative heterokaryon-derived plantlets were regenerated and 570 survived transplantation to soil. Experimentation was aimed at the introduction of proanthocyanidins (condensed tannins) from sainfoin, a bloat-safe plant, to alfalfa, a bloat-causing forage crop; however, no tannin-positive regenerant plants were detected. Most regenerant plants have shown morphological differences from the fusion parents, although, as expected, all resembled the "recipient" parent, alfalfa. Southern analysis using an improved total-genomic probing technique has shown low levels of sainfoin-specific DNA in 43 out of 158 tested regenerants. Cytogenetic analysis of these asymmetric hybrids has confirmed the existence of euploid (2n=32; 17%) as well as aneuploid (2n=30, 33-78; 83%) plants. Pollen germination tests have indicated that the majority of the hybrids were fertile, while 35% had either reduced fertility or were completely sterile.