Isolation of a series of chromosomal variants (2n=10 to 21) from an open-pollinated population of interspecific hybrids between Coix gigantea and Coix aquatica (Poaceae)

Abstract

A series of chromosomal variants has been isolated from an open-pollinated progeny of interspecific hybrids between aneuploids of Coix gigantea (2n = 18-24) and Coix aquatica (2n = 10). The interspecific hybrids (2n = 14, 15 and 16) produced several types of gametes not only with different chromosome numbers but also comprised of varied permutations and combinations ofgigantea and aquatica chromosomes. This was evident when the open-pollinated progeny obtained from these hybrids was screened chromosomally. Two such openpollinated experimental progenies were studied in two successive years (1983 and 1984) and plants with from 2n = 10 to 2n = 21 chromosomes were isolated. Chromosomal configurations at diakinesis in all the variants revealed frequent pairing between the gigantea and aquatica chromosomes. This indicated that the two species are phylogenetically closely related. Restoration of 'pure' parental species from the F1 hybids and chromosomal variants through genomic segregation and spontaneous back-cross are unique and noteworthy features.

Differential genome evolution and speciation of Coix lacryma-jobi L. and Coix aquatica Roxb. hybrid guangxi revealed by repetitive sequence analysis and fine karyotyping

“…Because certain Coix species have ten chromosomes[ 31 ], it is possible that C. lacryma-jobi is a tetraploid and C. aquatica HG is a hexaploid. According to previous reports, C. aquatica should be fertile and able to propagate by fertilization[ 32 ]. However, our karyotyping analysis revealed 10 chromosome pairs in C. lacryma-jobi and 10 paired plus 10 unpaired chromosomes in C. aquatica HG, implying the absence of any typical characteristics of a tetraploid or hexaploid genome (Figures 4 and 5 ).…”

Chromosomal basis of evolution in the genus Coix L. (Maydeae): a critical appraisal

“…In the open pollinated progenies of hybrids of C. aquatica and C. gigantea (presumably backcrossed to either parent), individuals with wide range of chromosome numbers (2n=10-21) with combinations of chromosomes of both the parents occurred and plants with parental genotypes were found more frequently than are expected normally [25,33,49,52]. Sapre and Deshpande [51] found at anaphase I in hybrids, segregation of all chromosomes of one parental genome to one pole and the other to another pole.…”

Chromosome studies in the grass subfamily Chloridoideae. I. Basic chromosome numbers

“…Garber (1950) and Celarier (1956) had already proposed that five was the basic chromosome number of the tribe Andropogoneae (Panicoideae). By 2000, Watson & Dallwitz reported a basic number of 5 for the panicoid genera Andropogon L., Coix L., Cymbopogon Spreng., Elionurus Kunth ex Willd., Sorghum, Thelopogon, and Zea L. (based on studies by e.g., Harlan & al., 1952;Sisodia, 1970;Dujardin, 1978a;Wu, 1978;Sapre & Barve, 1983;Molina & Naranjo, 1986Lavania, 1987;Sapre & Deshpande, 1987;Morakinyo & Olorode, 1988;Spies & al., 1991;Rao & Nirmala, 1994).…”