Reproductive success and compatibility among accessions of <i>Jatropha curcas</i> in Indonesia

Abstract

Large scale exploitation of Jatropha curcas for biofuel production is restrained by low productivity hence economically not protable. One of the main constraints is due to limited number of female owers in an inorescence which eventually develop into fruits that bear seed. Investigation on oral biology and reproductive potential of the species had been carried out, but seems to vary among sites. The research was conducted to study reproductive success and the compatibility among Indonesian Jatropha accessions. The research was set up in two experiments. The rst experiment was conducted at the Jatropha seed orchard, Pakuwon, Sukabumi, West Java from April to July 2007 using four-year- old trees of accessions from Lampung, Banten, West Java, and Central Java. The second experiment was conducted at Leuwikopo Experimental Station of Bogor Agricultural University from April to July 2008 using one-year-old trees of accessions from Lampung, Bengkulu, Palembang, and Kediri. Flowers were obtained from controlled self and cross-pollinated as well as left for open-pollination. The result showed that reproductive success varied among accessions; the greatest success was 0.73 obtained from aWest Java accession and the least was 0.53 from Banten accession. The Jatropha accessions were categorized as partially self-incompatible as indicated by index of self-incompatibility (ISI) that ranged 0.93- 0.99. Banten accession produced highly viable and vigorous seeds regardless of pollination methods; accessions of Central Java produced higher viability seeds when cross-pollinated within accession, whereas those from West Java and Lampung produced higher viability seeds when self-pollinated. Keywords: accessions, Jatropha curcas, selfpollination, self-incompatibility, seed viability