Progress 09/01/06 to 08/31/11

Outputs
OUTPUTS: The pecan [Carya illinoinensis (Wangenh.) K. Koch], a member of the family Juglandaceae, is an economically important nut crop. Propagation of pecan is done primarily by budding or grafting of improved cultivars onto seedling rootstocks. However, these methods suffer disadvantages such as considerable time, expense and poor transplanting survival of the plants. Propagation by cutting, though leads to uniform clonal rootstocks, is very difficult as the clones do not root readily. Even with the use of hormones, inconsistent results with only limited improvements have been reported (Brutsch et al., 1977; Smith et al. 1974; Wolstenholme and Allan 1975). In vitro propagation offers great potential for the pecan industry for large scale multiplication of selected clones and enables production of a high amount of constant quality plantlets within a very short time. We have developed an efficient method for in vitro propagation of pecan, a highly recalcitrant but commercially important nut crop. Nodal explants of various pecan cultivars were cultured on modified liquid woody plant medium (WPM) supplemented with 2% glucose and different concentrations of 6-benzylaminopurine (BAP; 0.44 - 44.39 miicromole). At least six to nine multiple shoots per explants were induced on modified WPM containing 13.32 mmole BAP after three weeks of culture. The efficiency of shoot induction was over 95%. The multiple shoots were proliferated and/or elongated on plant growth regulator free liquid WPM. Subsequently, the multiple shoots were separated and successfully rooted in liquid WPM containing 49.20 micromole indole-3-butyric acid. The efficiency of rooting was over 90% in most of the cultivars tried. The pecan plantlets were initially transferred to peat pellets and subsequently to the greenhouse. Evaluation of the regenerated plants in the field is underway in Arkansas and Mississippi. A post-doctoral research associate and six undergraduate students were trained in various aspects of micropropagation technology. Through this project, a strong collaboration has been established between UAPB and partnering institutions. The results obtained from this project were presented in several conferences such as 2008 World Congress on In Vitro Biology, Tucson, Arizona and Association of Research Directors, Inc. 15th and 16th Biennial Research Symposiums 2009 and 2011, Atlanta. The results were also presented to farmers in Arkansas during 2009 UAPB Field day as well as 2008 TriState Pecan Trade Show and Convention, Vicksburg, MS sponsred by the Pecan Producers of Louisiana, the Mississippi Pecan Growers Association and the Arkansas Pecan Growers Association. PARTICIPANTS: Dr. James O Garner and Dr. Muthusamy Manoharan- University of Arkansas at Pine Bluff- design and implementation of the experiments, project evaluation, dissemination of results and training of minority undergraduate students. Dr. Frank Matta- Mississippi state university- evaluation of pecan plants in the nursery and field Dr. Richard Heerema- New Mexico State University- evaluation of pecan plants in the nursery and field Dr. Girish Panicker- Alcorn State University- evaluation of pecan plants in the nursery and field A post-doctoral research associate and six undergraduate students were trained in micropropagation technology. TARGET AUDIENCES: Pecan growers in Arkansas and Mississippi. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
A simple and efficient protocol has been established for pecan micropropagation. At least 6-9 multiple shoots were induced on modified WPM containing 13.32 mmole BAP. The efficiency of shoot induction was over 95% and the efficiency of rooting was over 90% in most of the cultivars tried. The protocol established from this project will help to produce true type pecan plants. The equipment and supplies purchased from this project have strengthened our ability to conduct research and teach courses in biotechnology and molecular biology beyond the grant period. We have also trained six undergraduate minority students in research.

Publications

• N.N. Renukdas, M. Manoharan, and J. O. Garner 2010. In vitro propagation of pecan [Carya illinoinensis (Wangenh) K. Koch]. Plant Biotechnology 27: 211-215
• L. Garner, N. N. Renukdas, M. Manoharan 2011. In vitro propagation of pecan [Carya illinoinensis (Wangenh) K. Koch] rootstock. Association of Research Directors, Inc. 16th Biennial Research Symposium, Atlanta
• N.N. Renukdas, M. Manoharan, and J. O. Garner. 2009. In vitro propagation of pecan. Association of Research Directors, Inc. 15th Biennial Research Symposium, Atlanta., pp 181.
• M. Manoharan. 2008. Micropropagation of pecan. 2008 TriState Pecan Trade Show and Convention, Vicksburg, MS July 25 (invited talk).
• N.N. Renukdas, M. Manoharan and J.O. Garner. 2008. In Vitro plant regeneration of pecan [Carya illinoinensis (Wangenh.) K. Koch]. World Congress on In Vitro Biology 2008, Tucson, AZ, June 14-18 (P-3019).

Progress 09/01/08 to 08/31/09

Outputs
OUTPUTS: The objective of the project, In vitro propagation of elite pecan (Carya illinoinensis (Wangenh) K. Koch) cultivars, is to produce pecan plants through micropropagation. To this, an efficient method for in vitro propagation has been developed for pecan, a highly recalcitrant fruit species for micropropagation. Axillary buds from cultivars, Desirable and Cape Fear, were cultured on modified liquid woody plant medium (WPM) with different concentrations of 6-benzylaminopurine (BAP; 0.44-44.39 micromole). At least nine multiple shoots per explants were induced on modified WPM containing 13.32 micromole BAP after three weeks of culture. The efficiency of shoot induction was over 95% in both Cape Fear and Desirable cultivars. The multiple shoots were proliferated/elongated on hormone free liquid WPM. The multiple shoots were separated and successfully rooted in liquid WPM containing 49.20 micromole indole-3-butyric acid. The efficiency of rooting was over 90% in both Cape Fear and Desirable cultivar. The pecan plantlets were initially transferred to peat pellets and subsequently to the greenhouse. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Successful production of pecan plantlets from axillary buds.

Publications

• Renukdas, N.N., Manoharan, M., and Garner, J.O. 2009. In vitro propagation of pecan (Carya illinoinensis (Wangenh) K. Koch. ARD 15th Biennial Research Symposium, Atlanta, Georgia (P181)

Progress 09/01/07 to 08/31/08

Outputs
OUTPUTS: An efficient method for in vitro propagation has been developed for pecan [Carya illinoinensis (Wangenh) K. Koch], a highly recalcitrant fruit species for micropropagation. Axillary buds from cultivars such as Desirable and Cape Fear were cultured on modified liquid woody plant medium (WPM) with different concentrations of 6-benzylaminopurine (BAP; 0.44-44.39 micromole). At least nine multiple shoots per explants were induced on modified WPM containing 13.32 micromole BAP after three weeks of culture. The efficiency of shoot induction was over 95% in both Cape Fear and Desirable cultivars. The multiple shoots were proliferated/elongated on hormone free liquid WPM. The multiple shoots were separated and successfully rooted in liquid WPM containing 49.20 micromole indole-3-butyric acid. The efficiency of rooting was over 90% in both Cape Fear and Desirable cultivar. The pecan plantlets were intially transferred to peat pellets and subsequently to the greenhouse. This is a simple and efficient protocol that may be used to produce true-type pecan plants through micropropagation. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
In vitro propagation offers great potential for the pecan industry for large scale multiplication of selected clones and enables production of a high amount of constant quality seedlings within a very short time.

Publications

• Renukdas, N.N., Manoharan, M., and Garner, J.O. 2008. In vitro propagation of pecan ((Carya illinoensis (Wangenh) K. Koch). 2008 World Congress on In Vitro Biology, Tucson, Arizona (P-3019)

Progress 09/01/06 to 08/31/07

Outputs
Regeneration of plants through axillary buds and somatic embryogenesis are being established in pecan. Axillary buds of pecan var. Pawnee were used as explants. Woody Plant Medium (WPM) with different concentrations of thidiazuron (TDZ; 0.1-5.0 mg/l) 6-bezylaminopurine (BAP ; 0.1 - 5.0 mg/l) and combination of BAP: NAA (a-naphthalene acetic acid; 0.1 to 5.0 : 0.5 mg/l) and TDZ: NAA (0.1 to 5.0 : 0.5 mg/l) were used as culture medium. The pH of the medium was adjusted to 5.8 before autoclaving and was solidified with 0.35% w/v phytagel (Sigma). It was observed that the axillary buds inoculated on BAP (1.0 mg/l), TDZ (0.5 mg/l) and BAP: NAA (1.0:0.5 mg/l), TDZ: NAA (0.5:0.5 mg/l) elicited bud dormancy break than the other phytohormone concentrations. After the bud dormancy break, the explants were transferred to MS+BAP 0.2mg/l for further growth. After the shoot formation these explants were transferred to MS+BAP 0.2mg/l +IBA (0.1 mg/l) media for rooting. For somatic embryogenesis, immature zygotic embryo axis and nucellus were used as explants. WPM with different concentrations of 2, 4-D (0.1-5.0 mg/l) was used as culture medium. The pH of the medium was adjusted to 5.6 before autoclaving and was solidified with 0.35% w/v phytagel (Sigma). Six different varieties of pecan viz. Cape Fear, Choctaw, Shoshoni, Pawnee, Cheyenne and Chickasaw were used for the induction of somatic embryogenesis. Direct somatic embryogenesis was observed on media with 0.1, 0.5, 1.0, 5.0 mg/l 2, 4-D from the meristematic region of the zygotic embryo with embryo axis. No embryogenesis was observed from the nucellus explants. After embryo formation the somatic embryos were transferred to MS+BAP (0.1) medium and MS+BAP (0.1) + GA3 (Gibberellic acid; 0.1 mg/l) for elongation. Direct somatic embryogenesis was also observed from the embryo axis in Chickasaw variety in 2, 4-D medium at 0.5 mg/l concentration. Further elongation of plantlets obtained through axillary buds and somatic embryogenesis are in progress.

Impacts
Micropropagation or propagation in vitro of complete pecan plants, is a promising technique for large scale multiplication of selected clones. It has the advantages of small space requirements and reduced costs when compared to conventional vegetative propagation techniques. In vitro propagation enables the production of a high number of constant quality seedlings within a very short time.

Publications

• No publications reported this period