The impact of environmental and climatic variables on genetic diversity and plant functional traits of the endangered tuberous orchid (Orchis mascula L.)

Abstract

Understanding how environmental factors shape patterns of genetic and phenotypic variations in a species is necessary for conservation and plant breeding. However, these factors have not yet been completely understood in tuberous orchid species used to make ‘Salep’, an important ingredient in traditional medicine and beverages in middle eastern countries and India. In many areas, increasing demand has pushed species to the brink of extinction. In this study, 198 genotypes from 18 populations of the endangered species Orchis mascula L. spanning a large-scale climatic gradient in northern Iran were used to investigate patterns of genetic diversity and plant functional traits. Populations were sampled from three land cover types (woodland, shrubland, and pastureland/grassland). Plant height, stem length, number of flowers, bulb fresh and dry weight, glucomannan, and starch concentrations showed high variation among populations and were significantly related to land cover type. In general, genetic diversity was high, particularly in those from eastern Hyrcanian; additionally, populations showed a high level of genetic differentiation (G'st = 0.35) with low gene flow (Nm = 0.46). The majority of genetic differentiation occurred within populations (49%) and land cover types (20%). The population structural analysis using the AFLP marker data in K = 4 showed a high geographical affinity for 198 O. mascula genotypes, with some genotypes having mixed ancestry. Temperature and precipitation were found to shape genetic and phenotypic variation profoundly. Significant isolation by the environment was observed, confirming the strong effect of environmental variables on phenotypic and genetic variation. Marker-trait association studies based on MLM1 and MLM2 models revealed significant associations of P-TGG + M-CTT-33 and E-AGG + M-CGT-22 markers with plant height and glucomannan content. Overall, a combination of large-scale climatic variables and land cover types significantly shaped genetic diversity and functional trait variation in O. mascula populations.

Agro-morphological characterization and genotypic diversity of chilli (Capsicum. frutescens) landraces of Bangladesh

“…The results indicate that the 1000 seed weight of chilli germplasm is relatively stable while the yield plant -1 is unstable and may be influenced by different factors particularly annual climate variation and management practices [16]. Our results also support the findings of many workers [12] who reported environmental factors including precipitation, geographical region, altitude, and longitude contribute to the phenotypic polymorphism and functional traits of crop plants. Climate variables due to environmental gradients increase the genetic variabilities of crop plants [31].…”

“…The GIS map reveals that Mymensingh, Jamalpur, and Sherpur are nearby although each of them is administratively considered as separate units. The results are the evidence of prevailing environments and ecology of these three districts that plants can detect and respond to are likely to be homogenous as compared to that of Chattogram [13]. It is to be noted that, the climate of Bangladesh ranges from tropical to subtemperate but due to frequent seasonal changes and latitude-longitude differences, weather variations are evident from time to time and region to region.…”

“…Environmental changes with geographical gradients may also influence plant genetic diversity. Evidence is accumulating that environmental changes with geographical gradients (e.g., temperature and precipitation), influence plant genetic diversity [12]. The GIS map reveals that Mymensingh, Jamalpur, and Sherpur are nearby although each of them is administratively considered as separate units.…”