1a. Objectives (from AD-416)
Produce new knowledge of molecular biology, genetics, and crop traits of selected fruit, vegetable, and ornamental crops grown in Hawaii, and preserve selected sugarcane germplasm that is more suitable for growing in Hawaii. Use genetic engineering approaches to enhance the disease resistance of ornamentals such as anthurium and orchids. Develop improved germplasm for the nation’s sugarcane industry through increased biomass and/or sugar, increased resistance to abiotic stress, pathogens, and pests. Evaluate the horticultural characteristics of Jatropha, kukui, and other tropical crops for their potential as biofuel when grown in Hawaii. Assess the potential commercial application and the potential environmental and biosafety risks of transgenic plants that are developed.
1b. Approach (from AD-416)
Continue tissue culture multiplication of transgenic anthurium lines for subsequent screening by PBARC for bacterial and nematode resistance. Use HARC land to grow selected sugarcane lines that cannot be consistently maintained at the sugarcane clonal repository in Miami, Florida. Cross lines of material selected by the national sugarcane centers and distribute seeds from these crosses for their environmental selection for production of sugar and biomass. Cross lines of target crops to produce mapping populations for developing molecular markers associated with important agronomic traits. Use laboratory and field based approaches to evaluate and develop value added products from potential tropical biofuel crops, such as sugarcane, Jatropha, and kukui. Work with PBARC to develop risk mitigating gene constructs that consists of short-linked segments of genes or computer-generated consensus sequences derived from sequences of a family of genes or gene segments, and use them to develop transgenic plants, such as papaya, for resistance to pathogens and enhanced agronomic traits.
3. Progress Report
Several high yielding varieties of jatropha were identified and evaluated in replicated yield trials. Stand uniformity was achieved by planting seeds produced in isolated plots. Trees showed uniformity of branching and statistically significant uniformity of height, both of which are desirable for mechanical harvesting of seed. Trials showed that early stage aggressive pruning delayed fruit production and did not lead to higher yields. Irrigation trials identified one variety that performed better under low irrigation conditions than under high. At least seven varieties showed promise for future breeding. Three isolated plots of interest were established including; a supposed ‘non-toxic’ strain of jatropha from Mexico, a high oil content variety from China, and a male-sterile variety from Honduras. All present desirable traits for further study and breeding. Thirty-one high fiber Saccharum species, sugarcane varieties, and related grasses, e.g. banagrass (Pennisetum) where planted at Kunia in July 2010 for preliminary biomass evaluations and to produce seed for planting energy grass trials on Maui and the Big Island. Erect clones with high biomass were selected and will be planted for bioenergy feedstock field production trials in 2011. Results of this trial will be used in future screening to determine the best varieties for Hawaii’s diverse growing conditions and locations. Eleven Houma Canal Point (HoCP) sugarcane varieties imported from Houma, LA in 2009 flowered extensively in the fall of 2010 allowing crosses between them and the other HoCP varieties imported two years ago to HARC’s Maunawili Breeding Station. A total of 41 crosses were made in the fall of 2010 and the seed produced was shipped to ARS in Houma. Polymerase chain reaction (PCR) quantification of sugarcane yellow leaf syndrome virus (SCYLV) indicated that there may be more than one strain in Hawaii with differential capacity to elicit disease symptoms. Sequencing of SCYLV collected from a field at Maui Hawaiian Commercial & Sugar Co. (HC&S) and from the Hilo Agriculture Research Center (HARC) substation at Maunawili are being carried out to confirm the variability of SCYLV in Hawaii and to determine how the virus evolved and their relationship with symptoms. The project is monitored through on-site visits, meetings, telephone and email communications.