Table of Contents
López Benitez, A., F. Ramirez, S. Kuruvadi, and F.
Borrego. 1993. Interspecific hybridization between Parthenium
argentatum Gray and Parthenium lozanianum Bartlett. p. 347-348.
In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.
Interspecific Hybridization Between Parthenium argentatum Gray and Parthenium lozanianum Bartlett
A. López Benitez, F. Ramirez, S. Kuruvadi, and F. Borrego
- RESULTS AND DISCUSSION
- Table 1
The genus Parthenium has been classified into 16 different species
(Rollins 1950) from which only guayule (P. argentatum) contains
substantial amounts of good quality rubber. Interspecific hybridization in
guayule as a means of introducing desirable traits, requires basic information
on the breeding behavior of the interspecific hybrids with regard to fertility
and type of inheritance of the traits studied. In F1 hybrids between P.
argentatum and P. hispidum var. auriculatum, Hashemi et al.
(1987), reported that meiotic behavior was irregular as indicated by a low
pollen stainability and the limited number of viable BC1 seeds. In contrast,
Estilai et al. (1985), showed that guayule and P. schottii are readily
crossed and the F1 hybrids produced showed a partial fertility and high degree
of chromosome pairing. The inheritance of rubber content and morphological
characters in interspecific hybrids have been described by Naqvi et al. (1984),
as due to multiple gene action. A similar type of gene action has also been
described by Naqvi et al. (1987) for growth habit, morphological traits,
rubber, and resin contents of hybrids between guayule and P. fruticosum.
In this paper, we report the morphological characters, rubber content and
molecular weight, and resin content for hybrids between guayule and P.
lozanianum, and compare the hybrids to their progenitors.
Seed of diploid guayule and P. lozanianum were grown in the greenhouse.
Chromosome counts on P. lozanianum at meiosis indicated 2n = 108.
Diploid guayule proved to be self-incompatible, and was utilized as the female
without emasculation. Crosses were made in one direction transferring pollen
from P. lozanianum directly to the stigmas of guayule. Seed of parental
species and hybrids were collected when ripe, seeded separately in the
greenhouse and allowed to grow for 20 months. Plants were then sampled for
plant growth characteristics; and for rubber and resin analysis. Plant height,
plant spread, leaf length, leaf width, and peduncle length were determined from
10 individual plants of each parent and F1 hybrids. Rubber and resin analysis
were performed on the same 10 plants according to Holmes and Robbin (1974).
Rubber quality as estimated by molecular weight was determined for both parents
and F1 hybrids according to Campos Lopez and Angulo Sanchez (1975).
Table 1 presents morphological data, rubber content, rubber molecular weight,
and resin content of P. argentatum, P. lozanianum, and their
interspecific F1 hybrids. Plant height and spread, and leaf shape, length and
width were the most conspicuous morphological differences between P.
argentatum and P. lozanianum. Average leaf length of P.
argentatum and F1 hybrids was about 30% lower than P. lozanianum.
Leaf widths of P. lozanianum were 30% of guayule and hybrids. Peduncle
length of the hybrids was larger than either parent. Hybrids were easy to
recognize because of the intermediate nature of many morphological and
agronomic traits as compared to the two parental species. The intermediate
nature of the morphological characteristics of interspecific F1 hybrids in the
genus Parthenium has been pointed out by Naqvi et al. (1984, 1987) who
suggested a polygenic type of gene action for these traits. Rubber content in
guayule (6.82%) was about 12 times greater than P. lozanianum (0.56%)
but F1 hybrids had an average of 4.6% which is about 67% of that in guayule.
Although P. lozanianum did not improve the rubber percentage of the
hybrids, the total rubber production could be improved if biomass increased as
indicated by Tysdale (1950).
The small traces of rubber found in P. lozanianum showed higher
molecular weight than guayule. This trait was found in the hybrids indicating
a dominant type of gene action. Campos Lopez and Angulo Sanchez (1975)
indicated that the rubber from either Hevea or guayule should have a
molecular weight of at least 2 million to be considered of good quality. Our
results suggest that P. lozanianum could be utilized to improve rubber
quality of guayule.
- Campos Lopez, E. and J.L. Angulo Sanchez. 1975. Molecular weight
characterization of natural guayule rubber by gel-permeation chromotography.
Polymers Letters Edition 14:649-652.
- Estilai, A., A. Hashemi, and, V.B. Yougner. 1985. Genomic relationship of
guayule with Parthenium schottii. Amer. J. Bot. 72:1522-1529.
- Hashemi, A., E. Estilai, and J.E. West. 1987. Relationship of woody
Parthenium argentatum and herbaceous P. hispidum var.
auriculatum (Asteraceae). Amer. J. Bot. 74:1350-1358.
- Holmes, R.L. and H.W. Robbins. 1947. Rubber determination in young guayule.
Studies on the Spence and Caldwell method. Anal. Chem. 19:313-317.
- Naqvi, H.H., A. Hashemi, J.R. Davey, and J.B. Waines. 1987. Morphological and
cytogenetic characters of F1 hybrids between P. argentatum and P.
fruticosum var fruticosum and their potential rubber improvement.
Econ. Bot. 41:66-67.
- Naqvi, H.H., V.B. Yougner, and E. Rodriguez. 1984. Inheritance of rubber
content and morphological traits in F1 hybrids between Parthenium
argentatum and P. schottii. Bul. Torrey Bot. Club. 3:337-382.
- Rollins, R.C. 1950. The guayule rubber plant and its relatives. The Gray
Herbarium of Harvard University, Cambridge, MA.
- Tysdale, H.M. 1950. Apomictic interspecific hybrids are promising for rubber
production from guayule. Agron. J. 42:351-355.
Table 1. Morphological traits and rubber content of P. argentatum,
P. lozanianum and their F1 hybrids grown in the greenhouse for 20 months.
|Variable ||P. argentatum ||P. lozanianum ||F1 hybrid|
|Height (cm) ||46.7±3.0 ||110.6±6.9 ||64.7±9.2|
|Width (cm) ||42.0±3.1 ||84.5±5.2 ||47.0±10.7|
|Length (cm) ||6.0±0.8 ||8.3±3.0 ||5.6±0.4|
|Width (cm) ||1.7±0.3 ||5.4±2.9 ||1.7±0.2|
|Peduncle length (cm) ||12.2±1.7 ||10.6±2.2 ||17.6±4.5|
|Head width (cm) ||5.3±0.3 ||5.1±0.3 ||5.3±0.4|
|Content (%) ||6.8±0.7 ||0.6±0.1 ||4.6±0.7|
|M.W. ||1.95x106 ||2.27x106 ||2.21x106|
|Resin (%) ||8.3±0.9 ||5.3±0.9 ||7.8±1.2|
Last update April 18, 1997