title: In vitro induction  of tetraploid garlic  with trifluralin.
abstract: Garlic  (Allium sativum) is propagated asexually. Since sexual cross breeding is  almost impossible, means for effective breeding are not currently available and  the available production cultivars are seriously aged and degenerated. A  possible alternative for breeding is chemical induction. Trifluralin, a type of  herbicide, has been reported to provoke chromosome doubling. However, this  chemical had not been tested on garlic. We tested various trifluralin  concentrations and treatment durations for efficiency in the induction of  tetraploid garlic. A clove base of garlic with a stem cv. Gailiang was used as  the ex-plant to induce calluses on Murashige and Skoog (MS) medium; the  calluses were then inoculated onto MS medium containing different levels of  trifluralin and cultured to induce chromosome number variation in vitro.  Garlic calluses were effectively induced via the ex-plant and both shoots and  roots differentiated well on MS medium containing 6-benzylaminopurine at 3.0  mg/L and indole-3-acetic acid at 0.1 mg/L. However, increases in trifluralin  concentration and treatment duration reduced the survival rate and  differentiation rate of calluses. Garlic callus cultured for 15 days on medium  containing 100 μM  trifluralin gave the highest rate of chromosome doubling. Through observation  of chromosome number in the root apical cells and the morphology of guard cells  on the leaf epidermis of the regenerated plantlets, it was clear that  chromosome number variation was induced and tetraploids were produced in  vitro by trifluralin treatment.
authors.affiliation: College of Horticulture, Northwest A & F University, Yangling, Shaanxi, China. chengzh@nwsuaf.edu.cn
authors.forename: Z-H
authors.initials: ZH
authors.lastname: Cheng
authors.forename: X-J
authors.initials: XJ
authors.lastname: Zhou
authors.forename: M A
authors.initials: MA
authors.lastname: Khan
authors.forename: L
authors.initials: L
authors.lastname: Su
authors.forename: H-W
authors.initials: HW
authors.lastname: Meng
mesh_terms: D001593:Benzyl Compounds; D032461:Chromosomes, Plant / Q000235:genetics; D004171:Diploidy; D005737:Garlic / Q000187:drug effects* / Q000235:genetics*; D007210:Indoleacetic Acids / Q000494:pharmacology; D007701:Kinetin / Q000494:pharmacology; D018519:Meristem / Q000166:cytology / Q000187:drug effects; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development; D054046:Plant Stomata / Q000187:drug effects; D011687:Purines; D057891:Tetraploidy; D046509:Tissue Culture Techniques / Q000379:methods*; D014274:Trifluralin / Q000494:pharmacology*
chemical_list: D001593:Benzyl Compounds; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D011687:Purines; C034182:1-naphthaleneacetic acid; D014274:Trifluralin; C480551:benzylaminopurine; D007701:Kinetin