Effects of cutting and fertilizing treatments before wintering on the overwintering ability in relation to growth characteristics among six Panicum varieties
1999
Cai, Q. (Miyazaki Univ. (Japan). Faculty of Agriculture) | Ishii, Y. | Ito, K.
To further clarify the determinant factors of tiller composition before wintering on overwintering ability among Panicum grasses. (i.e. Natsukaze, Gatton and Green panic in P. maximum and Makarikari-grass, Tamidori and Tayutaka in P. coloratum) cutting and fertilizing treatments were conducted. In all treatments, the varieties ranked Makarikari-grassTayutaka and GattonGreen b Panic for their overwintering ability which was evaluated by the index of overwintering (IOW, determined by the regrowth ratios of both plant and tiller number in spring to those in early winter), while Natsukaze and Tamidori were unable to overwinter. Among the four varieties which did overwinter, the IOWs were improved by increasing midway cutting from once to twice, when plants were cut firstly in late July and secondly in early September, but they were not improved if the second cut was delayed later than September. The improvement in the IOWs by an increase in fertilization was positive in Gatton and Makarikari-grass, but was slightly negative in Green panic and Tayutaka. These results for the improvement in the IOWs under both treatments were verified to be mainly associated with the decrease in the percentage of reproductive tillers, and the increase in the number of vegetative tillers possessing a certain number of green leaves before wintering. These results also suggested for maintaining a certain amount of green leaves to accumulate photosynthate before wintering under the favorable tiller
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