Assessing the potential of native ecotypes of Poa pratensis L. for forage yield and phytochemical compositions under water deficit conditions

Authors: SHARIATIPOUR, NIKWAN - Shiraz University; HEIDARI, BAHRAM - Shiraz University; SHAMS, ZAHRA - Shiraz University; Richards, Christopher

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2022
Publication Date: 1/21/2022
Citation: Shariatipour, N., Heidari, B., Shams, Z., Richards, C.M. 2022. Assessing the potential of native ecotypes of Poa pratensis L. for forage yield and phytochemical compositions under water deficit conditions. Scientific Reports. 12. Article e1121. https://doi.org/10.1038/s41598-022-05024-1.
DOI: https://doi.org/10.1038/s41598-022-05024-1

Interpretive Summary: Understanding the genetic heritability of drought related traits in Poa pratensis has impact of developing more climate resilient pasture and forage crops. One approach is to systematically screen genotypes collected in the wild and assess their naturally occurring adaptive tolerances to drought stress in a controlled, multiyear field trials. We assessed over 100 individual genotypes of P. pratensis collected in the wild and evaluated them for drought tolerance including yield components and polyphenol compounds thought to be associated with tolerance to low water conditions. The combined data of forage yield and phytochemical traits over the two years were used for multivariate analyses to determine the most important variables accounting for the forage yield variability. By screening this diverse germplasm, it is hoped that promising genotypes can be identified as parents for further breeding improvement programs.

Technical Abstract: Analysis of genetic diversity and germplasm evaluation lay a foundation for genotype selection and improvement of varieties for drought tolerance in Kentucky bluegrass. The present study was conducted to assess the genetic potential of a collection of Kentucky bluegrass for drought stress and to identify the association between polyphenol compounds and forage yield traits. One hundred genotypes were clonally propagated in a greenhouse and evaluated in the field under two moisture environments (normal and deficit irrigation) in 2018 and 2019. High variation was observed among the genotypes for all measured traits. Drought stress had negative effects on fresh and dry forage yields and reduced genotypic variation. On average, drought stress reduced fresh and dry forage yields by 45% and 28%, respectively. The Mantel test for the relationship between forage yield traits and geographical distances suggested that an increase in the geographical distance of collected accessions did not affect forage yield. Genetic coefficients of variation for forage yield and most of the phytochemicals were lower under drought stress, suggesting that deficit irrigation may reduce genetic variation for the tested traits. The estimates of heritability were higher under normal irrigation conditions than under drought stress treatment for forage yield traits and few polyphenols. However, the majority of polyphenol compounds had higher heritability than forage yield traits under drought stress, which suggests the potential for indirect selection. Genotypes ‘Ciakhor’, ‘Damavand’, ‘Karvandan’, ‘Abrumand’, and ‘Abr2’ had high quantities for polyphenols and yield traits under both moisture regimes. These genotypes are promising candidates for use in breeding programs and for developing high-yielding varieties under water-deficit conditions.