Effect of sire population on the genetic diversity and fitness of F1 progeny in the endangered Chinese endemicSinocalycanthus chinensis

Abstract

Sinocalycanthus chinensis Cheng et S. Y. Chang (Calycanthaceae), which has a unique systematic status, is listed as a national second-class protected plant of China. In this study, the genetic diversity, performance, and fitness of F1 progeny from crosses between the Damingshan (DMS) population of S. chinensis and pollen parents from the Daleishan (DLS) and Longxushan (LXS) populations were examined. The DLS population has a relatively small population size, low genetic diversity, and considerable geographical and genetic distances from the DMS population relative to the LXS population. Compared with naturally occurring seeds, DLS-sired seeds had the highest thousand-seed weight, starch content, fat content, germination rate, germination index, and emergence rate, but the lowest protein content. Naturally occurring, open-pollinated seeds had the lowest thousand-seed weight, starch content, and fat content, but the highest protein content. Compared with natural F1 progeny, DMS × DLS seedlings had the highest genetic diversity, photosynthetic parameters, and growth characteristics, except for leaf mass ratio and stem mass ratio. Under strong light, DMS × DLS seedlings exhibited a F v /F m value of 0.75, while the other two seedling types exhibited F v /F m values of 0.65. DLS-sired seeds had the most vigorous growth characteristics except for leaf mass ratio and stem mass ratio. These results suggest that genetic rescue by transplanting seedlings from the DLS population or hand pollination with pollen from the DLS population would be effective methods to reduce inbreeding depression and obtain strong offspring with high genetic diversity and fitness in the DMS population. K E Y W O R D S genetic diversity, genetic rescue, inbreeding depression, offspring fitness, Sinocalycanthus chinensis

Environmental predictors of seed germination in two Halocnemum species from Mediterranean (Balearic, Tyrrenic and Adriatic) and Red Sea coastal salt marshes

“…Indeed, these authors further discussed how the perennial and annual halophytes living in different environments had developed particular strategies to maintain genetic diversity and to ensure enough variability to guarantee its survival in such a changing environment. Other studies relate fitness measured as germination success, among other parameters, to genetic diversity (Greimler and Dobeš, 2000; Ali et al, 2006; Crawford and Whitney, 2010; González-Varo et al, 2010; Li et al, 2020). Nevertheless, some authors report that seed responses are more related to environmental aspects than to genetic diversity (Heinicke et al, 2016; Rodríguez-Rodríguez et al, 2018), which might be mediated by epigenetic processes (Zhang and Ogas, 2009), whereas some specific genes have been associated with germination success in stressful environments (Liu et al, 2020; Rehman et al, 2020).…”