Effects of Short-Day and Gibberellic Acid Treatments on Summer Vegetative Propagation of Napier Grass (Pennisetum purpureumSchumach)

Yasuyuki Ishii,Asuka Yamano,Sachiko Idota

doi:10.1155/2016/9606914

Abstract

The effects of short-day (SD) and gibberellic acid (GA3) treatments on promoting vegetative propagation during the summer were examined in Napier grass (Pennisetum purpureumSchumach). A dwarf variety of late heading type (DL) Napier grass was exposed to three SD treatments (5, 10, and 20 short days plus a spray of 400 ppm GA3solution following each SD treatment, GASD) or no treatment (control). Additionally, then, a dwarf variety of early heading (DE) and the normal variety of Merkeron (ME) were exposed to 10 days of GA-SD treatment together with nontreated controls. For DL and DE, GA-SD treatments showed the following effects: 10-day GA-SD treatment increased significantly (P<0.05) the length of lateral tiller buds, maintained a high rooting percentage, and increased the diameter of the tiller buds. This resulted in a taller plant, one with enhanced tiller numbers, and thus a greater number of established nursery plants for the two dwarf varieties. In contrast, there was only a limited positive effect of the GA-SD treatments on the normal variety, ME. Thus, 10 days of GA-SD treatment was judged to be the most effective treatment for promoting lateral tiller bud elongation and early maturation in tiller buds for the two dwarf varieties of Napier grass.

Highlights

Napier grass (Pennisetum purpureum Schumach) belongs to a tropical C4 grass with high dry matter productivity [1, 2] and it can elongate its stem internode without phase transition from the vegetative to the reproductive state
Diameter, and rooting of tiller buds showed a significant effect of GA-SD and/or SD treatments for all of 5, 10, and 20 days of treatment periods at 5% level (Table 1)
The GA-SD treatments significantly increased the internode length at the 3rd node, tiller bud length at the 1st to the 5th nodes, tiller bud diameter at the 3rd node, and tiller bud rooting at the 1st node, all relative to the control plants and relative to the SD plants

Summary

Introduction

Napier grass (Pennisetum purpureum Schumach) belongs to a tropical C4 grass with high dry matter productivity [1, 2] and it can elongate its stem internode without phase transition from the vegetative to the reproductive state. Napier grass rarely produces viable seed and is commonly propagated vegetatively using stem cuttings and rooted tillers [1, 7, 8]. Vegetative propagation of Napier grass was accomplished with cell-tray nursery plants [10, 11], the propagation season was strictly limited to the late autumn. It is difficult for these late-autumn propagated nursery plants to be transplanted in the field soon after propagation due to the frost damage. Nursery plants needed to be maintained in the glasshouse over the wintering season

Methods

Results

Conclusion