Artificial hybridization of rubber-bearing guayule with cold-tolerant Parthenium ligulatum
- Univ. of Califorina, Riverside (USA) Univ. of California, Davis (USA)
Caespitose and cold-tolerant plants of Parthenium ligulatum (Jones) Barneby (Asteraceae) from a native population in the Uinta Basin, Utah, were uprooted, potted, and transferred to a greenhouse in California. Approximately two years after transfer, the plants flowered and subsequently were crossed to diploid guayule (Parthenium argentatum Gray), the rubber-bearing species, native to the state of Durango, Mexico. Only female guayule {times} male P. ligulatum crosses produced F{sub 1} hybrids. Only crosses involving guayule as female parent and F{sub 1} plants as male parent produced backcross (BC{sub 1}) plants. Hybrid plants were variable with respect to their growth habit, inflorescence, and leaf shape. Both parents and F{sub 1} hybrids had 2n = 36 chromosomes. Unlike the parents, however, meiosis was irregular in the hybrids which showed a range of 0-5 and an average of 2.1 univalents at metaphase I. Hybrids averages 0.87 laggards at anaphase I and 0.83 micronuclei at the tetrad stage. The crossability of guayule and P. ligulatum, the high degree of chromosome pairing of the F{sub 1} hybrids, and the production of BC{sub 1} plants indicate that the two species are related in spite of their of distinct morphological and ecological differences. This study suggests that the cold-tolerance trait of P. ligulatum may be transferred to guayule through interspecific hybridization followed by backcrossing.
- OSTI ID:
- 7180049
- Journal Information:
- American Journal of Botany; (USA), Vol. 75:2; ISSN 0002-9122
- Country of Publication:
- United States
- Language:
- English
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