Interspecific Hybridization in Cotton: Recovery of Wild Species Cytoplasms

P.F. Umbeck and J. McD. Stewart


 
ABSTRACT

In an interspecific hybrid program the complete utilization of wild species germplasm requires their use as female as well as male parents. In cotton, very few wild species cytoplasms have been recovered and introgressed into cultivated cottons. The purpose of this investigation is to expand the available cytoplasms for introgression. Using the wild species as a maternal parent, several new interspecific hybrids have been recovered. Here, we report the results of two hybrids, Gossypium stocksii (El) x G. hirsutum (AD)l (Acala G-8160; a glandless breeding line) and G. somalense (E2) x G. arboreum cv. Nanking (A2).

Cytogenetic analysis of the microspore mother cells revealed the following chromosome associations at metaphase I. For the F1 triploid hybrid E1 x (AD)1, the respective frequency of univalents and bivalents was 35.2 and 1.9. No other multivalent configurations were observed. The univalent and bivalent formations per cell ranged from 31-39 to 0-4. Chiasma frequency per bivalent was 1.06. Phenotypically, vegetative characteristics were intermediate between the parents but expression of the glanded trait was associated with the E1 genome.

In the F1 diploid hybrid E2 x A2, the frequency of univalents, bivalents and trivalents was 21.2, 2.1 and 0.2. The respective range per cell for each class was 14-26, 0-6 and 0-1 with a chiasma frequency per bivalent of 1.24. Vegetatively, this hybrid is quite depauperate when compared to the parents. Crosses between E2 and either (AD)l or (AD)2 were unsuccessful. In reciprocal crosses, embryos and seedlings have been obtained but mature plants could not be recovered. Our observations suggest some degree of genetic incompatibility between the AD genome of cultivated cotton and the E2 genome.



Reprinted from Proceedings of the 1983 Beltwide Cotton Production Research Conference pg. 91
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998