Agronomic and molecular characterization of <i>Chloris gayana</i> cultivars and salinity response during germination and early vegetative growth

Abstract

Chloris gayana is a warm-season grass, often cultivated in areas where soil salinity is a major constraint for forage production. Five cultivars (2 unselected populations and 3 synthetic varieties) were evaluated through agronomic traits as well as Inter Simple Sequence Repeats (ISSRs) and Sequence-related Amplified Polymorphism (SRAP) molecular markers. The consensus between both agronomic and molecular data sets was high (&gt;99%) suggesting that both systems provided similar estimates of genetic relationships. The analysis revealed that synthetic varieties, Finecut, Topcut and Santana, were the most genetically different cultivars, whereas the unselected populations, Pioneer and Katambora, were closely related. Responses to salinity stress during germination and early vegetative growth stages were evaluated in only the synthetic varieties. The results showed that Finecut and Santana were able to germinate in the same proportion as controls even at concentrations of 200 mM NaCl. Under hydroponic conditions, Santana attained approximately 20% higher total dry weight than the other 2 varieties and the longest roots. Finecut presented the highest root dry weight. These results suggested that Santana and Finecut showed high salinity tolerance at germination and early vegetative growth stages, both crucial phases when seeking a successful pasture establishment, particularly in saline environments. Further studies in the field are needed to determine if these hydroponic results are reproduced under field conditions.

Genetic Diversity and Population Structure of a Rhodes Grass (Chloris gayana) Collection

“…There are only a few reports on the application of conventional molecular markers to Rhodes grass genetic studies. ISSR, SRAP and AFLP markers have been used to study diploid and tetraploid cultivars [9,13]. A genetic linkage map of Rhodes grass was developed using AFLP and RFLP markers [12].…”

“…Conventional molecular marker technologies, such as inter simple sequence repeats (ISSR), amplified fragment length polymorphisms (AFLP), sequence-related amplified polymorphisms (SRAP) and restriction fragment length polymorphisms (RFLP), have been used to study a few known Rhodes grass cultivars [8][9][10][11][12][13], although the results of these previous studies were limited in their abiltiy to provide insight into the genetic diversity of the species, both by the number of genotypes included and the low density markers used. Despite its potential economic importance in drought and saline affected environments and the fact that it is a genetically polymorphic species, genomic studies have been limited, making Rhodes grass one of the orphan crops in the application of molecular genetics.…”

Genetic Diversity and Population Structure of a Rhodes Grass (<em>Chloris gayana</em>) Collection

“…A genetic linkage map of Rhodes grass was developed using AFLP and RFLP markers [12]. However, in most cases, the markers were used to differentiate a small number of known cultivars [8][9][10][11][12][13]. In addition, as only a few cultivars were included, the scope of these studies was limited to inferring how the results would apply to the wider genetic diversity and population structure in the Rhodes grass germplasm from around the world.…”

“…Conventional molecular marker technologies, such as inter simple sequence repeats (ISSR), amplified fragment length polymorphisms (AFLP), sequence-related amplified polymorphisms (SRAP) and restriction fragment length polymorphisms (RFLP), have been used to study a few known Rhodes grass cultivars [8][9][10][11][12][13]. Despite its potential economic importance in drought and saline affected environments and the fact that it is a genetically polymorphic species, genomic studies have been limited making Rhodes grass one of the orphan crops in the application of molecular genetics.…”

Methodological proposal for the characterization of accessions in Germplasm Banks using Generalized Procrustes Analysis applied to incomplete but connected trials

“…Once the iterative process of the GPA ends, the total variability can be partitioned in the form of a table of analysis of variance (ANOVA). Some applications of this technique are related to measuringthe consensus between the agronomic and molecular information (1,3,10,18,20,22,26). On the other hand, GPA can be applied in crop characterization and other agronomic objectives (4,19,23,27).…”