2009 Annual Report
The integrating of Hawaii’s sugarcane breeding activities began with those of the U.S. mainland to assist variety improvement programs of ARS in Houma, LA and Canal Point, FL. Fourteen leading U.S. sugarcane clones having reluctant flowering on the mainland were imported for hybrid seed production under Hawaii’s heavy flowering conditions. Hybrid seed from these crosses will be returned to their respective ARS breeding stations for evaluation.
Production continues of new sugarcane cultivars for Hawaii and the mainland through hybridization and evaluation of the progeny for disease reactions and yields across contrasting environmental zones. Progeny was produced from several interspecific crosses to develop molecular marker mapping populations of S. officinarum, S. robustum, and S. spontanaeum.
Yield trials were conducted of high fiber canes vs. commercial hybrids to assist DNA marker identification of high fiber for bioenergy genotypes. Germplasm was collected from multiple sources and planted trials of potential biofuel perennial crops (Jatropha, Kukui, and Moringa) for initial field evaluations and eventual breeding and selection for agronomic improvements. Kukui, Hawaii’s candlenut tree is so slow-growing that no data is available for this species as a potential oil crop. Moringa seed oil content was measured as 29.6% by weight but the oil potential of this crop problematic because of the difficulty in harvesting seed from such a large tree. Most extensive work was on Jatropha from 6 locations: India, Madagascar, Honduras, Mexico, Oahu, and Hawaii. Jatropha flowered year-round in replicated field plots with heavy bursts in early summer, early fall and produced fruits within 6 months after planting in all test plots. In 1 test plot comparing seed origins and irrigation rates, the highest yielding plots had produced enough seed to yield ~56 gallons of oil per acre after 14 months. Selections of superior trees have begun with trees from India and Madagascar showing the highest potential productivity. Isolated plots of clonally propagated material produced selfed seed for future field establishment to reduce plant-to-plant variation; biggest roadblock to Jatropha commercialization. Honduras germplasm showed significant genetic variation in leaf size, fruit cluster size, seed size, and appears to hold the most potential for long-term crop improvement, especially with the identification of a male-sterile tree (first of its kind observed in Hawaii).
Methods for sugarcane transformation were improved; P0 protein of the Sugarcane Yellow Leaf Virus was evaluated for its ability to suppress transgene silencing in sugarcane.
Vasconcellea monoica, the only monoecious species of the family Caricaceae, was the source of a BAC library used to produce physical map of the sex determining region to demonstrate an autosomal origin of the papaya sex chromosome 4.2 to 4.8 million years ago.
A papaya BAC library was used to produce a BAC-based physical map to assist whole genome shotgun sequence assembly and integration with the genetic map.
ADODR monitored project via cooperator meetings, progress report, and email and telephone communications.