Excised leaf sections of lance coreopsis cultured on Murashige Skoog (MS) medium produced adventitious shoots in response to BA. When the combinations of 0, 0.5, 1, or 2 μm NAA with 0, 5, 10, 20, or 40 μm BA were tested, shoots were induced by any of the four BA concentrations used in the medium, regardless of the presence of NAA. The average number of shoots formed per leaf section ranged from 1.4 to 4.3 seven weeks after culture initiation. Roots were induced at the base of individual shoots on the same regeneration medium when cultures were kept longer than 7 weeks. The rooted plants were transferred successfully into soil. The regenerated plants had the same growth and flowering characteristics as the seed-grown plants. Chemical names used: benzyladenine (BA); naphthaleneacetic acid (NAA).
Chiwon W. Lee, Joel T. Nichols, Lijuan Wang, and Shanqiang Ke
108 POSTER SESSION (Abstr. 362–374) Cell and Tissue Culture I
Xingping Zhang and Billy B. Rhodes
Tetraploids are needed to synthesize triploid watermelons, which produce “seedless” fruit with improved quality. Traditionally, the tetraploids are induced by applying colchicine to the growing apex of seedlings or soaking the seeds with colchicine solution. This method often produces low frequency of tetraploids and high frequency of chimeras. Breeding tetraploids takes much longer time than breeding diploids because of the low female fertility. We developed a tissue culture approach that allows breeders to develop desirable tetraploids with commercially acceptable volume of seed in 2 years. This tissue culture approach includes: 1) regenerate plants via shoot organogenesis from cotyledon tissue; 2) screen tetraploids based on leaf morphology (more serrated leaf margin and wider leaf shape) before transplanting, and confirm tetraploids based on pollen morphology (larger pollen with four copi) and/or seed characteristics; 3) self-pollinate tetraploids or cross the tetraploids with diploids to accurately estimate the female fertility; 4) micropropagate the best tetraploid(s) using axillary buds during the off-season; and 5) produce tetraploid seed from the cloned tetraploids in an isolation plot and evaluate the triploids derived from the tetraploid(s) in the following season. This approach has been practiced on more than 20 genotypes over the past 4 years.
Mustapha Benmousea and Yves Desjardine
We have developed tissue culture and protoplasts isolation protocols for Asparagus densiflorus in order to use this genetic material in the breeding of Asparagus officinalis. For tissue-culture of A. densiflorus, the conditions which optimize the induction and the production of callus are a full MS medium with 1 mg/L of both pCPA and BAP and 0.5 mg/L of thiamine. HCL in the dark. on this medium, we obtained a friable white callus. Indirect organogenesis was obtained if pCPA was omitted from the medium. Replacement of the plant growth regulators by 2,4-D and Kinetin produced a hard and compact callus which did not differentiate. Protoplast have been isolated from 10 days old friable callus. cell wall was digested with 0.3% macerase, 1% cellulase and 0.8% rhozyme for a period of 16h at a temperature of 27°C in a CPW medium. Protoplast yield was 2 ×106 protoplasts/g callus. osmolarity of the digestion solution was 0.8 M provided with a mixture of glucose (0.6 M) and mannitol (0.2 M). cells were then plated at a density of 1 × 105 cells per ml. Microcolonies formed on a 1/2 MS medium with 0,5 mg/L NAA and ZEA and 1 g/L glutamine in the dark.
Janet E.A. Seabrook and Gerald Farrell
Stock plants of `Shepody' and `Yukon Gold' potato (Solarium tuberosum L.) were grown in a greenhouse and irrigated with city water. Contamination rate of stem explant tissue cultures excised from these stock plants was 50% to 100%. A comparison of the microorganisms isolated from the contaminated cultures and from 0.22-μm filter disks through which 20 liters of city water had passed revealed the presence of similar bacterial floras. Five genera of bacteria (Listerium spp., Corynebacterium spp., Enterobacter spp., Pasteurella spp., and Actinobacillus spp.) were isolated from contaminated cultures and cultured filter disks. Watering greenhouse-grown stock plants with filtered city water decreased contamination of stem explant cultures 30% to 50%. Installing an ultraviolet light water-sterilizing unit at the greenhouse inlet point effectively reduced contamination.
Sameer Pokhrel, Bo Meyering, Kim D. Bowman, and Ute Albrecht
for seed propagation ( Bisi et al., 2020 ). For these reasons, it is valuable to also make use of alternative propagation methods such as cuttings and tissue culture to produce genetically identical rootstocks that can be used as liners for grafting
The influence of the culture chamber size and medium volume on the growth rates of shoot tips of peas, lettuce, kidney beans, and spearmint were determined after 8 weeks of incubation. Cultures were grown in a variety of culture chambers including culture tubes, baby food jars, Magenta GA-7 containers, 1-pint Mason jars, 1-quart Mason jars used with and without an automated plant culture system (APCS), 0.5-gal Mason jars with and without an APCS, Bio-safe chambers with an APCS, and polycarbonate culture chambers with an APCS having culture chamber volumes of 55, 143, 365, 462, 925, 1850, 6000, and 16,400 ml, respectively. Plans are presented for the construction of various culture chambers used in an APCS. The APCS consisted of a peristaltic pump, media reservoir containing 1 liter of liquid nutrient medium, and a culture chamber. Cultures grown with an APCS consistently produced higher fresh weights than cultures using any of the agar culture systems tested. Growth rates varied considerably depending on the plant species and culture system tested. Peas, lettuce, and spearmint exhibited flowering only when grown in the APCS. A cost comparison using the APCS versus various conventional tissue culture systems is presented.
Qudsia Hussaini, Chiwon W. Lee, and Shanqiang Ke
139 POSTER SESSION 21 Cell & Tissue Culture/Cross-Commodity
R.N. Trigiano, K.M. Kaveriappa, S.E. Schlarbaum, M.T. Windham, and W. Witte
93 ORAL SESSION 19 (Abstr. 129–135) Cell and Tissue Culture
Kh. A. Okasha and M. E. Ragab
177 POSTER SESSION 25 (Abstr. 870-901) Cell and Tissue Culture/Propagation