Comparison of the Genetic Structure betweenIn Situ and Ex Situ Populations of DongxiangWild Rice (Oryza rufipogon Griff.)

Abstract

In situ and ex situ conservation are two main wild rice (Oryza rufipogon Griff.) protection strategies. Few studies have compared the genetic diversity and genetic structure of wild rice between ex situ and in situ populations. Thus in this study, 278 individuals collected from three in situ and nine ex situ populations of Dongxiang wild rice (DXWR) were genotyped using 32 microsatellite loci to compare their population genetic structure and genetic diversity. Model‐based grouping, neighbor‐joining tree, and principal coordinate analyses showed that there were significant differences in the population structure between in situ and ex situ populations. The in situ populations clustered into three major groups, which were in accordance with their geographical distribution (Anjiashan, Zhangtang, and Shuitaoshu). However, the nine ex situ populations of DXWR showed no differences among populations, and there was a high heterozygosity for each individual. In addition, one of the in situ populations (Zhangtang) was not represented in the ex situ conservation garden. Given the above results, we concluded that the germplasm of both in situ and ex situ populations are precious, and that the combination of these two conservation strategies is necessary to protect the germplasm resources of DXWR, but special emphasis should be placed on in situ conservation to better maintain their genetic identities. In addition, it is necessary to recollect genetic resources from in situ populations for ex situ conservation, especially from the Zhangtang population.

Genetic diversity and selection signatures in maize landraces compared across 50 years of in situ and ex situ conservation

“…Under this framework, comparing ex situ and in situ conservation strategies can contribute to a better understanding of their underlying effects on the maintenance of agrobiodiversity and to increase their effectiveness. Previous comparisons between these two conservation strategies in different crops have determined the following: (i) agrobiodiversity may be lost (Hammer et al 1996 ; Teklu and Hammer 2006 ) or conserved (Mekbib 2008 ; Bezançon et al 2009 ); (ii) farmers may conserve agrobiodiversity to manage climate uncertainty (Orozco-Ramírez and Astier 2017 ; Fenzi et al 2015 ), diversify their diets (Ortega-Paczka 1973 ), obtain profits and fulfill traditional uses (Rice 2007 ; Wang et al 2017 ); (iii) in situ populations may contain higher diversity than ex situ accessions (Yang et al 2005 ; Barry et al 2008 ; Deu et al 2010 ; Sun et al 2012 ; Liu et al 2017 ); and (iv) ex situ accessions may experience drift or inbreeding during regenerations (Parzies et al 2000 ; Gómez et al 2005 ). However, while comparing the genetic diversity of ex situ landrace accessions with landrace samples collected later in the same locations may provide insights about the outcomes of the conservation strategies, it does not allow to pinpoint evolutionary processes ongoing in situ.…”

Improvement of Salt Tolerance Using Wild Rice Genes

“…Dongxiang wild rice, which was the northernmost population of common wild rice naturally grown in Jiangxi Province, China (N28.14) (Gao et al, 2000 ; Liu et al, 2017 ), was crossed to a cultivated japonica rice Ningjing16 (NJ16) four times (Figure 1 ). The salt tolerance of introgression lines was evaluated against NJ16 and a reference cultivar 96D10, which was widely planted in North China.…”