BREEDING FIELD CROPS FOR ORNAMENTAL PURPOSE: A CASE IN Jathropa spp.

Populations of F1, F2 and BC1F1 were formed from an interspecific cross between green-flowered Jatropha curcas and red-flowered J. integerrima (dwarf type) to observe for segregation in flower colors and to select for ornamental segregants. The crossing to produce F1 and BC1F1 was successful only when J. curcas was used as the female parent. The suitable time for crossing was between 08:00 – 13:00 o’clock with fruit setting rate of 65-78%. The F1 segregated into white- and pink-flowered plants. While flowers of the F2 population segregated into nine different colors, viz. light green, green, white, very light pink, light pink, pink, deep pink, very deep pink, and red. When J. curcas was backcrossed by a pink-flowered F1, its BC1F1 progenies segregated into green, light green, white, very light pink and light pink flowers. While another set of BC1F1 progenies obtained from a white-flowered F1 parent segregated into green, light green, and white. The segregating progenies in both sets showed smaller plants than jatropha and bore colorful flowers suitable for ornamental purpose. Six plants were chosen and registered at Kasetsart University and the Thai Department of Agriculture as commercial cultivars, ‘Kamphaeng Saen 1’ to ‘Kamphaeng Saen 6’

Overcoming crossing barriers between jatropha (Jatropha curcas L.) and castor bean (Ricinus communisL.)

Abstract A limitation in improvement of jatropha (Jatropha curcas) has been the low genetic variation among the available germplasm. An alternative to create genetic variability and incorporate desirable traits is through wide crossing. Due to reproductive barriers, wide crossing in jatropha has had limited success. In this experiment, intergeneric hybridization between jatropha and castor bean (Ricinus communis) was performed. In both direct and reciprocal crosses, a few stigma-compatible pollen grains were found. The pollen tube grew normally and reached the style base within an hour after pollination, but the embryo aborted a few days later. This indicated that the hybridization barrier was post-fertilization and thus the ovules were excised, cultured in MS medium supplemented with 1 mg L-1 IAA, and subcultured every four weeks. Finally we obtained one intergeneric hybrid plant, which was vegetatively propagated for further study

Two jatropha karyotypes constructed from meiotic pachytene chromosomes: Pericentric distribution of heterochromatin and variation in repetitive DNAs.

Jatropha (Jatropha curcas) is an oil-bearing plant used for biodiesel production. Construction of its standard karyotype and identification of the euchromatin/heterochromatin distribution associated with gene expression and meiotic recombination are essential to fully characterize its genome. Here, we developed a J. curcas karyotype based on meiotic pachytene chromosomes. In addition, a karyotype of J. integerrima, a useful species for jatropha breeding, was also constructed. Five out of eleven J. curcas chromosomes were metacentric, but only two were metacentric in J. integerrima. Almost all of the heterochromatin was distributed around the pericentric regions. The interstitial and distal regions were euchromatic without heterochromatic knobs, except for small heterochromatin regions associated with the subtelomeric repeat sequence JcSat1. These pericentric heterochromatin distribution patterns, together with chromosome structure data and the results of FISH probing with rDNA and JcSat1, allowed us to classify all chromosomes of both species. The two species had two 35S rDNA loci and one 5S rDNA locus; one 35S rDNA locus in J. integerrima was located on the interstitial region of the short arms. In addition, JcSat1 was found at only the heterochromatic ends of the J. curcas chromosome, not the J. integerrima chromosome. Despite the same chromosome number, the two pachytene chromosome-based karyotypes suggest variation in chromosome structure and distribution of repetitive DNAs in these two species

Mapping of QTLs for Seed Phorbol Esters, a Toxic Chemical in Jatropha curcas (L.)

Jatropha (Jatropha curcas L.) is an oil-bearing plant that has potential to be cultivated as a biodiesel crop. The seed cake after oil extraction has 40–50% protein that can be used in animal feeds. A major limitation in utilizing the cake is the presence of phorbol esters (PE), a heat-tolerant toxic chemical. To identify the quantitative trait loci (QTLs) for PE, we constructed a genetic linkage map from an F2 population of 95 individuals from a cross “Chai Nat” × “M10” using 143 simple sequence repeat (SSR) markers. M10 is low in seed PE while Chai Nat is high. Seeds from each F2 individual were quantified for PE content by high performance liquid chromatography. A single marker analysis revealed five markers from linkage group 3 (LG3) and nine markers from LG8 associated with seed PE. Inclusive composite interval mapping identified two QTLs, each on LG3 (qPE3.1) and LG8 (qPE8.1) responsible for the PE. qPE3.1 and qPE8.1 accounted for 14.10%, and 15.49% of total variation in seed PE, respectively. Alelle(s) from M10 at qPE3.1 increased seed PE, while at qPE8.1 decreased seed PE. qPE3.1 is a new loci for PE, while qPE8.1 is the same locus with that reported recently for PE