Reproductive biology of the native forage grass Trichloris crinita (Poaceae, Chloridoideae)

Abstract

Trichloris crinita is a perennial forage grass species native to arid regions of the American continent. Due to its extensive area of distribution, good forage quality and resistance to drought and grazing, this species is widely utilised as forage and for revegetation purposes in environments with low water availability. Despite its importance, genetic improvement of T. crinita has been very limited, partly as consequence of the lack of knowledge on its mode of reproduction. In the present work, we studied the reproductive biology of T. crinita by means of embryological analyses, flow cytometric seed screen (FCSS), self-compatibility tests and progeny testing with morphological and molecular markers. Cytological analyses revealed embryo sacs with eight nuclei and of Polygonum type for all T. crinita accessions analysed. FCSS histograms exhibited two clear peaks corresponding to 2C and 3C DNA content, indicating embryo sacs of sexual origin. Controlled pollination experiments designed to evaluate seed set (%) demonstrated that T. crinita is self-compatible, whereas results from morphological and simple sequence repeat (SSR) marker analysis of progeny revealed lack of outcrossing. Together, these results indicate that T. crinita reproduces sexually. It is a self-compatible and autogamous species. It is expected that these data will have a positive impact in the genetics and breeding of this species, and therefore contribute to its proper utilisation in arid regions.

Exploiting genetic and physiological variation of the native forage grass Trichloris crinita for revegetation in arid and semi‐arid regions: An integrative review

“…(), conclusively demonstrated that T. crinita seeds develop sexually (i.e., through double fertilization). In addition, pollination experiments performed in both studies concluded that T. crinita is self‐compatible, because all the plants analysed produced seeds under self‐pollination conditions (Gutiérrez et al., ; Kozub et al., ). In these studies, self‐pollination was ensured by isolating inflorescences in moderately transparent paper bags 2 days prior to anthesis.…”

“…The general pattern of floral development observed in this species is similar to that described for other self‐pollination grasses, including small millets (Gupta, Sood, Agrawal, & Bhatt, ) and many Australian native grasses (Whalley, Chivers, & Waters, ). Dense inflorescences and profuse flowering, as reported in T. crinita (Kozub et al., ), are believed to favour selfing and probably cause a certain amount of spontaneous self‐pollination by geitonogamy (Barrett, ).…”

“…They produce dense inflorescences composed of digitate racemes, solitary and small spikelets with one sterile floret and a fertile one below. Glumes are lanceolate, laterally compressed, pubescent and persistent, with the upper glume apex being acuminate and composed of three awns, the central awn longer than the laterals awns (Anton, Zuloaga, & de Rúgolo Agrasar, ; Kozub et al., ). Lack of cleistogamous spikelets was reported in a recent study that analysed ~ 2,000 spikelets from 20 T. crinita accessions (Kozub et al., ).…”

“…Very recently, Kozub et al. () and Gutiérrez, Richard, and Cerino () determined that T. crinita reproduces by means of sexuality, being the species self‐compatible and autogamous. Sexuality was determined through embryological analyses in both studies.…”

Flow cytometric seed screen data are consistent with models of chromosome inheritance in asymmetrically compensating allopolyploids

“…Several seeds of both Onosma species showed larger P ind values, with the mean P ind = 3.22 for O. arenaria and 2.98 for O. pseudoarenaria. (42,(65)(66)(67)(68)). This is the first study evaluating the genome composition in ACAs and associating the genome composition with the FCSS results.…”