Author
|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/16/2011 Publication Date: 2/7/2012 Citation: Knoll, J.E., Anderson, W.F. 2012. Vegetative propagation of napiergrass and energycane for biomass production in the southeast USA. Agronomy Journal. 104:518-522. Interpretive Summary: Napiergrass and energycane are two high-biomass perennial grasses that are being studied as potential bioenergy crops for the Southeast USA. Reproducing these crops by seed is not practical, so vegetative propagation must be used. These grasses can be propagated by stem cuttings, or billets, in a similar manner as for sugarcane. The purpose of this study was to determine the best methods for napiergrass propagation, and to determine the optimal planting times for both napiergrass and energycane in the Southeast Coastal Plain. A greenhouse-based experiment was carried out using two-node cuttings of ‘Merkeron’ napiergrass. The results showed that either horizontal buried planting or vertical planting with one node exposed can be used to establish cuttings. Cuttings taken from the lower portion of the parent stem were superior to younger material from the upper portion. The rooting hormone indole-3-butyric acid (IBA) was applied at varying doses, but did not affect propagation success. Two field-based experiments were conducted at Tifton, GA across two years. In the first experiment eight napiergrass breeding lines and the cultivar Merkeron were compared for response to cutting length. Cuttings contained one, two, five, or ten nodes, and each plot contained ten total nodes. Cuttings were planted in the fall, and shoot emergence was monitored until mid-winter. Shoot growth was again counted the following spring. Single-node cuttings tended to produce more shoots per plot initially in the fall, but many of these did not survive the winter. Generally, higher emergence percentages were achieved with five- and 10-node cuttings. In the second field experiment, seven napiergrasses and two energycanes were compared for response to planting date using ten-node cuttings. Five bi-weekly plantings were made beginning September 17, 2009, and six plantings beginning September 2, 2010. As in the previous experiment, emergence was monitored until mid-winter and spring growth was measured. In 2009 initial fall emergence was greater in earlier plantings, but the following spring, both early and late plantings had similar numbers of shoots per cutting, while intermediate plantings had the least. In 2010 there was less variation in fall emergence among planting dates, but the following spring the earliest plantings had more shoots per cutting than later plantings. In the Coastal Plain, closer to the northern range of adaptation for these grasses, planting by mid-September is recommended, while later plantings may be more risky. Technical Abstract: With renewed interest in planting large areas to bioenergy crops, improvements in establishment methods are needed. Our objectives were to evaluate propagation methods with stem cuttings of napiergrass (Pennisetum purpureum Schum.), and to determine the optimum planting date for napiergrass and energycane (Saccharum hyb.) in the Southeastern Coastal Plain of the USA. A greenhouse study with ‘Merkeron’ napiergrass showed only minor differences between horizontal buried planting and vertical planting with one node exposed. However, cuttings taken from the lower portion of the parent stem were superior to younger material from the upper portion. The rooting hormone indole-3-butyric acid (IBA) did not affect propagation success. Nine napiergrass genotypes were compared for response to cutting length in the field (one, two, five, or 10 nodes cutting-1, with 10 nodes plot-1). Single-node cuttings tended to produce more shoots plot-1 initially in the fall, but many of these did not survive the winter. Generally, higher emergence percentages were achieved with five- and 10-node cuttings. Seven genotypes of napiergrass and two of energycane were compared for response to planting date. Five bi-weekly plantings were made beginning 17 Sept. 2009, and six plantings beginning 2 Sept. 2010. In 2009 initial fall emergence was greater in earlier plantings, but the following spring, both early and late plantings had similar numbers of shoots cutting-1, while intermediate plantings had the least. In 2010 there was less variation in fall emergence among planting dates, but the following spring the earliest plantings had more shoots cutting-1 than later plantings. |
