Physiological and Biochemical Responses of Forage Grass Varieties to Mild Drought Stress Under Field Conditions

Abstract

In view of the expected increase in drought periods, researchers and breeders are searching for forage grasses that are more tolerant to drought stress. This study wanted to examine the physiological and biochemical reactions of nine forage grass varieties belonging to Festuca, Lolium and Festulolium under mild drought stress conditions in a semi-controlled field experiment. A mild drought stress treatment was applied in the period between cut II and cut III using three large mobile rain-out shelters equipped with sprinkler irrigation systems. The experiment consisted of two soil moisture treatments: (1) control where a soil moisture level of around 20% v/v was maintained and (2) drought stress where the soil moisture level decreased to 7.5% v/v. The experiment was cut 5 times in 2014 and 4 times in 2015. A total of nine varieties from five species of forage grasses were evaluated: L. perenne, L. multiflorum, F. pratensis, F. arundinacea and F. braunii. Dry matter yield, gas exchange parameters and chlorophyll fluorescence were significantly lower in drought stress than under control conditions and the physiological parameters reacted within 2 weeks after the start of the drought treatment in all species. In contrast, drought stress significantly increased water use efficiency, the content of proline, phenolic acids, flavonoids, water soluble carbohydrates and decreased neutral and acid detergent fibre on both years. Based on total dry matter yield and tolerance indices the most drought tolerant species were L. multiflorum in the first and F. arundinacea in the second investigated year.

WITHDRAWN: Classification of Megathyrsus maximus Accessions Grown in The Colombian Dry Tropical Forest by Nutritional Assessment during contrasting seasons

“…This condition might be related to the average height of germplasm of 118 vs 79 cm during rainy and dry seasons, respectively. Therefore, growth in height could result from the leaf material reduction and respective digestibility (Kalmbacher et al 1980), and possibly the drought stress may delaying maturity which can improved organic matter digestibility of forages (Fariaszewska et al, 2020). The correlations found in the M. maximus collection were similar to those reported by Stabile et al (2010) with commercial cultivars.…”

“…In tropical regions of Colombia, there are productive differences between commercial cultivars, which could be associated with aspects inherent to morphology (Patiño et al, 2018) and nutritional pro le, these are advantageous characteristics in terms of adaptation to different livestock systems Some studies suggest that in vitro and in vivo digestibility of organic matter increases with rainy seasons (Vargas et al, 2013 andSilva TVS et al, 2017) and others show that water stress did not signi cantly affect the digestibility of organic matter (OMD) (Fariaszewska et al, 2020). The ndings in this research found ADF decreased and IVDMD slightly increased during the dry season compared to the rainy season.…”

Selecting plant traits for soil erosion control in grassed waterways under a changing climate: A growth room study

“…Under summer establishment, the Drought condition reduced stem diameter and AGB in all treatments except for the Conv treatment. Fariaszewska et al (2020) found that AGB for Festuca, Lolium and Festulolium decreased following a period of drought, which concurs with the present study, where all the treatments containing Festulolium had a lower AGB under drought conditions. However, Conv, a mixture of Festuca rubra and Lolium perenne, did not conform to the findings of Fariaszewska et al (2020).…”

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

“…At T2, soil water availability was not yet limiting (83% REW, Figure 2), but VPD was high (3.06 kPa, versus 2.51 kPa at T1) ( Table 1), suggesting that Lp has a more strict stomatal regulation to atmospheric conditions than Fa. This confirmed other studies that reported larger stomatal conductance values of Fa under control conditions [15] and stomatal closure occurring at lower (i.e., more negative) leaf water potential than Lp [86,87]. These differences in stomatal control can be caused by several mechanisms.…”

“…In addition, tetraploid varieties have a more open sward and are less persistent [12]. Although Festuca arundinacea (Fa) has a lower feeding quality than Lp, its yield potential is larger, especially under drought conditions, owing to its deeper rooting [13][14][15].…”