Cytological studies in a pentasomic of 2n = 12 Coix taxon

Abstract

Among a natural population of Coix aquatica Roxb., a pentasomic (2n+3; 2n=15) was isolated and studied cytologically for the first time. The extra homologous chromosomes in the plant behaved normally, as they did not disturb the rest of the bivalents through meiosis except for the stickiness and rare occurrence of a few univalents and chromosome fragments. The majority of pollen mother cells (PMCs) showed five bivalents and a pentavalent at diakinesis. The different anaphase segregations led to the formation of hypo-and hyper-ploid male gametes from n-1 (n=5) to n+4 (n=10) chromosomal constitutions. Although the chromosomal configurations towards the later stages were found to be sticky in most of the meiocytes, the meiosis was clean, giving rise to pollens that appeared to be normal. The plant yielded a few fertile seeds also. The origin of this higher polysomic is considered to be through the fusion of male and female super haploid gametes produced by the trisomics that arose from the 2n=12 Coix taxon.

Cytology of two varieties of <i>Coix lacryma-jobi</i> L. (Poaceae) in India

“…puellarum is distributed in Southeast Asia (Xi et al 2016;Madhav and Gosavi 2022a, b). In the C. lacryma-jobi different cytotypes were reported such as n=5 and 10; 2n=10, 16, 20, 21, 22, 27, 29, 30, 31, 39, 40, and 41 (Koul and Paliwal 1964;Koul 1965;Rao 1973Rao , 1977Venkateshwaralu et al 1976;Christopher and Mini 1988;Christopher and Jacob 1990;Rao and Nirmala 1993;1994a, b, 2001Christopher et al 1995aChristopher et al , b, 1996Christopher et al , 1997Nirmala 2003;Han et al 2004;Barve and Sangeetha 2008;Gosavi and Yadav 2011;Cai et al 2014). Among them 2n=20 is dominated number in the C. lacryma-jobi (Liu et al 2020) and the same result we have got in the present investigation of C. lacryma-jobi var.…”

“…(Madhav and Gosavi 2022a). Because of high variations in morphology and habitat in the genus Coix, many workers have done cytological works in different taxa (Koul and Paliwal 1964;Rao 1977;Clayton 1981;Sapre et al 1985;Christopher and Mini 1988;Jacob 1990, 1991;Han et al 2004;Barve and Sangeetha 2008;Gosavi and Yadav 2011;Rao and Nirmala 2011;Cai et al 2014), but now most of the taxa subsumed and few kept under variety rank. Thus, to understand the species, variety, and variations of the Coix need to thoroughly work on cytology.…”