Publication Date

1985

Location

Kyoto Japan

Description

As part of a study on the adaptability of timothy cultivars to environmental conditions, the effects of high temperature stress on growth and digestible dry matter content were examined using the following cultivars: Kunpii (extremely early maturing), Senpoku (early), Nosappu (early), Erecta R. v. P. (medium), and Hokushu (late). Three levels of temperature treatment employed in this study were 23/18 (Tl), 31/26 (TI), and 31/31°C (T3) (day/night) for 10 days. High temperature treatment for 10 days resulted in an obvious decrease in dry weight and RGR at TI, which might be mainly caused by the decrease in NAR. These values at TI were higher than those at T3. Dry weight, RGR, NAR, and LAR varied according to the cultivars used, Kunpu is assumed to have the highest resistance to the high temperature stress among the cultivars tested. It is assumed that an adaptability to the relatively high temperature of this new cultivar may be derived from the breeding work. The percent digestible dry matter (DDM) of timothy plants examined was decreased as a result of the high temperature in the order of TI, T3, and Tl. Twenty days after the completion of the treatment, T3 (i.e. the lowest growth) showed the highest DDM, while Tl showed the lowest. Among the cultivars tested, Hokushu showed the highest DDM, while Kunpu had the lowest.

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Effects of High Temperature Stress on Growth and Digestible Dry Matter Content of Timothy Cultivars

Kyoto Japan

As part of a study on the adaptability of timothy cultivars to environmental conditions, the effects of high temperature stress on growth and digestible dry matter content were examined using the following cultivars: Kunpii (extremely early maturing), Senpoku (early), Nosappu (early), Erecta R. v. P. (medium), and Hokushu (late). Three levels of temperature treatment employed in this study were 23/18 (Tl), 31/26 (TI), and 31/31°C (T3) (day/night) for 10 days. High temperature treatment for 10 days resulted in an obvious decrease in dry weight and RGR at TI, which might be mainly caused by the decrease in NAR. These values at TI were higher than those at T3. Dry weight, RGR, NAR, and LAR varied according to the cultivars used, Kunpu is assumed to have the highest resistance to the high temperature stress among the cultivars tested. It is assumed that an adaptability to the relatively high temperature of this new cultivar may be derived from the breeding work. The percent digestible dry matter (DDM) of timothy plants examined was decreased as a result of the high temperature in the order of TI, T3, and Tl. Twenty days after the completion of the treatment, T3 (i.e. the lowest growth) showed the highest DDM, while Tl showed the lowest. Among the cultivars tested, Hokushu showed the highest DDM, while Kunpu had the lowest.