Development of triploid daylily (Hemerocallis) germplasm by embryo rescue

• Published in: Euphytica Vol. 169; no. 3; pp. 313 - 318
• Main Authors: Li, Zhiwu, Pinkham, Linda, Campbell, N. Faith, Espinosa, Ana Carolina, Conev, Rumen
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.10.2009; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: acclimation; Agronomy. Soil science and plant productions; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; chromosomes; Cultivars; culture media; diploidy; embryo (plant); embryo culture; Embryos; Environmental testing; flow cytometry; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; Genetic resources, diversity; Genetics and breeding of economic plants; Genotype & phenotype; Genotypes; germplasm; Growth regulators; Haploidy, in vitro culture applications, somatic hybrids; Hemerocallis; Hybridization; Life Sciences; micropropagation; nursery crops; ornamental plants; Plant breeding: fundamental aspects and methodology; plant genetic resources; Plant Genetics and Genomics; Plant growth; Plant material; Plant Pathology; Plant Physiology; Plant Sciences; root tips; sucrose; tetraploidy; triploidy; wide hybridization; Tissue culture; Flow cytometry; Polyploidy; Micropropagation; Cytology; Embryo rescue; Monocotyledones; Ornamental crop; Liliaceae; Germplasm; Hemerocallis; Angiospermae; Genetic improvement; Spermatophyta; Triploidy
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-009-9958-8

Interploidy crosses between diploid daylily (Hemerocallis) cultivars (2n = 22) and tetraploid cultivars (2n = 44) were performed via in vivo hybridization aiming to produce triploid hybrid germplasm (3n = 33). Plant growth regulator-free MS based medium containing 5 levels of sucrose--1, 2, 3, 4 or 5% was used to optimize the embryo rescue medium. It was determined that the medium supplemented with 3% sucrose gave highest rate of immature hybrid embryo rescue. Thirty-seven hypothetically triploid genotypes were subjected to verification of ploidy status by root tip chromosome counting and flow cytometry. Thirty-one of them were confirmed triploids. These genotypes were in vitro propagated, acclimatized to ex vitro conditions, and planted for future field performance evaluation and environmental testing. The newly developed triploid genotypes could open new horizons for further polyploidy breeding.