Phenological Changes In Jatropha curcas Accessions Under South Florida Environmental Conditions

Jatropha (Jatropha curcas, Euphorbiaceae) has been identified as a potential biofuel species. The oil extracted from seeds has proven characteristics as an excellent biodiesel fuel and it has been tested in diesel engines and in jet fuel mixes.  However, breeding in jatropha is practically nonexistent. Important in breeding programs, data on leaf and flower initiation can lead to the identification of early, mid-season and late genotypes. The objective of present study was to describe the phenological changes in jatropha accessions planted at Tropical Research and Education Center of the University of Florida, in Homestead, Florida. We selected 110 2-year-old trees of jatropha representing 17 accessions from 12 countries for evaluations. The trees lose their leaves during winter; therefore daily observations on flower initiation were recorded between April and May 2010 and leaf initiation was recorded between February and March 2011, when new leaves emerged. The first floral buds were observed during the last week of April 2010. On April 23, 2010, 46% of all accessions presented flowers. In accessions from Mexico flowers initiated on May 12, 2010, thus classified as late genotypes. New leaves started emerging on February 03 continuing through March 30, 2011 with different start dates for the accessions. Two accessions from Indonesia and Honduras were the earliest. Between March 21 and March 28, 78% of all accessions started leaf initiation, and were characterized as mid-season genotypes. All 11 accessions from Mexico remained leafless through March. Only 1.8% of accessions evaluated were classified as early genotypes while 10% of all accessions evaluated were classified as late genotypes. The average difference between an early genotype and a mid-season genotype was 46 days. Leaf and flower initiation can be affected by water availability, temperature, photoperiod, and genotype. In this study, differences between accessions were genotypic and indicate an existing level of genetic variability. The evaluation and utilization of such variability is essential in breeding programs and can contribute for the development of cultivars that are suitable for different agro-climates.