Genetic variation in an orchardgrass population promises successful direct or indirect selection of superior drought tolerant genotypes

Abstract

Improvement in drought tolerance is an important component of forage grass breeding. To assess the potential of selecting drought tolerant genotypes of orchardgrass, a polycross population was created in 2010 and evaluated in the field under normal and drought stress conditions during 2011-2013. Drought stress reduced performance in forage yield, growth characteristics, and most of the physiological traits measured, but increased carotenoid content, proline content, and the chlorophyll a/b ratio. High estimates of narrow-sense heritability for chlorophyll and carotenoid content, as well as forage yield components, indicated that phenotypic selection would be successful in achieving genetic progress. Indirect selection to improve forage yield under drought stress conditions was efficient through selecting for chlorophyll a, chlorophyll b, total chlorophyll and carotenoid content. These physiological traits were also significantly associated with drought tolerance index. Overall, families 5, 7, 8, 13, 14 and 24 with high stress tolerance index values and high forage yield under both water conditions were identified as suitable families for breeding drought adaptive varieties. K E Y W O R D Sdrought, orchardgrass, physiology, selection

Multivariate and multiharvesting trial for agronomic traits in the genetic resources of guineagrass

“…Plant height in Poaceae is a trait that has high heritability (Abtahi et al, 2018;Entio et al, 2021;Kapoor, 2017Kapoor, , 2020, independent of precipitation conditions, which confirms that the variation is mainly due to additive genetic effects, and that phenotypic selection could contribute to genetic advancement for this trait (Abtahi et al, 2018).…”

“…In our study, 97% of the collection had plant height >70 cm, and the correlations of plant height with biomass yield superior to .33 show that guineagrass under tropical edaphoclimatic conditions similar to those of the Patía Valley develops desirable agronomic characteristics for the production and maintenance of productive livestock grazing systems. Correlations above .50 are also seen with native European Poaceae in normal conditions and those with hydric stress (Abtahi et al., 2018, 2019).…”

“…Different authors agree on the importance of the trait plant height. One explanation is the close and positive relationship between plant height and forage yield in perennial grasses (Abtahi et al., 2018; Braz et al., 2017; Filho et al., 2004; Ojo et al., 2021; Roy et al., 1999). In this research, we found a positive and moderate correlation >33% between plant height and DMY and GFW and acknowledge that the production of grasses in tropical countries is a variable to consider in the adoption processes by farmers (Mwendia et al., 2019).…”

“…Such knowledge also helps with the identification of desirable, resilient, and high‐yielding genotypes in various regions with diverse climatic stresses (Ebrahimiyan et al., 2013; Irani et al., 2015; Karimizadeh et al., 2013). Estimation of the heritability of forage yield and a majority of the physiological traits allow us to carry out phenotypic selection of materials that support genetic advances in agronomic traits (Abtahi et al., 2018; Pirnajmedin et al., 2018).…”

Applying RGB- and Thermal-Based Vegetation Indices from UAVs for High-Throughput Field Phenotyping of Drought Tolerance in Forage Grasses

“…First, it can relate to the chlorophyll content in the leaves. In breeding studies, this is particularly useful when investigating the stress-sensitivity of the different genotypes [95]. Chlorophyll content can be best quantified with vegetation indices based on spectra in the red edge [34].…”