The present study was conducted to analyze agronomic characteristics of 8 ecotypes of Arundinella hirta (A. hirta) and the correlation among them. Changes in phenotypic characteristics of 8 ecotypes were measured at equal intervals of time from May to September. Among ecotypes, Jangsoo-1 has the highest plant height (172.33 cm), number of leaves (9.00) and leaf length (55 cm) while the ecotype Youngduk has the highest leaf width (1.57 cm), fresh mass (26.63 g), dry mass (7.06 g), number of spikelets per spike (53.33), amount of seeds per spike (0.74 g) and amount of seeds per 10 spikes (7.23 g). The ecotype Jinju-1 has the shortest plant height (119 cm) and leaf number (6.33), while Okgye-2 has shortest leaf length (30.67 cm), leaf width (0.93 cm), fresh mass (12.60 g), dry mass (3.30 g), spike length (30.33 cm), spikelet per spike (39.67), amount of seeds per spike (0.61 g) and amount of seeds per 10 spikes (6.00 g). Correlation coefficients were estimated among the studied agronomic characteristics which showed positive and significant association with each other. In the present study, the agronomic data collected would be useful to understand the potential of A. hirta as a forage resource and helpful in selecting the high-yielding genetic resource for future forage improvement.

This study was conducted to investigate the effect of waterlogging stress on the physiological response and growth characteristics of the five Italian ryegrass varieties. For all varieties, the germination rate of seed decreased by 10-15% as the waterlogging period increased, but the waterlogging stress treatment after the early seedling stage increased the growth of shoot and root length. Photosynthetic activity (Fv/Fm) according to waterlogging stress treatment decreased in all vareity, and Florida 80 showed the least decrease with 1.5%. Waterlogging stress treatment was found to reduce the accumulation of reactive oxygen species (malondialdehyde, MDA) and the activities of antioxidant enzymes. These results suggest that other mechanisms may be involved in the defense mechanism of Italian ryegrass against waterlogging stress, such as promoting root growth to escape from waterlogging stress, in addition to the antioxidant enzyme system.

The increase in temperature due to climate warming is predicted to affect crop yields in the future. Until now, various types of OTC (open top chamber) that simulate the future climate condition have been developed and used to study the effect of temperature increase due to global warming on maize growth. However, in most OTCs, high equipment and maintenance costs were required to artificially increase the temperature. This study was carried to develop a cost-effective and simple OTC suitable for climate warming experiments for forage maize. Three octagonal OTCs with a height of 3.5 m × a diameter of 4.08 m and a partially covered top were constructed. The lower part of OTC covered film was opened at a height of 26 cm (OTC-26), 12 cm (OTC-12) from the ground surface, or not opened (0 cm, OTC-0). Mean air temperatures during the daytime on a sunny day in OTC-0, OTC-12 and OTC-26 increased to 3.23℃, 1.33℃, and 0.89℃, respectively, compared to the ambient control plot. For a pilot test, forage maize, ‘Gwangpyeongok’ was grown at OTCs and ambient control plots. As a result, in the late maize vegetative growth phase (July 30), the plant height was increased more than 45% higher than the ambient control plot in all OTC plots, and the stem diameter also increased in all OTC plots. These results indicate that it is possible to set the temperature inside the OTC by adjusting the opening height of the lower end of the OTC, and it can be applied to study the response of forage maize to elevated temperature. An OTC, with its advantages of energy free, low maintenance cost, and simple temperature setting, will be helpful in studying maize growth responsiveness to climate warming in the future.

Aluminum (Al) stress in acidic pH is known to decrease the growth and productivity of alfalfa. However, not much is known about how the application of silicon (Si) affects the Al stress response in alfalfa. This study was conducted to evaluate the effect of exogenous application of Si on the growth of alfalfa seedlings exposed to Al stress in pots. Alfalfa seedlings grown in pots for 2 weeks were treated either Al stress (pH 4.0, 0.2 mM Al) or Al stress + Si (1 mM) for 5 days, lengths and biomass of shoot and root, and chlorophyll and carotenoid contents in leaf tissues were analyzed respectively. Al stress treatment inhibited shoot and root growth, and decreased fresh and dry weights, and chlorophyll content in leaves, but increased carotenoid content. In contrast, when alfalfa seedlings treated with Al stress combined with Si, delayed growth caused by Al stress of shoot and root of alfalfa seedlings was restored, dry weight was increased and chlorophyll content of leaf tissue was increased, but carotenoid content was decreased. These results suggest that Si has a function of alleviating Al toxicity in alfalfa, of which it exhibits a mitigating effect by a function that overlaps with some of the intracellular functions of carotenoids.