This study aimed to identify the parental palms with high mean and general combining ability (GCA), and the progenies with high mean and specific combining ability (SCA) for bunch yield and bunch component traits. A total of30 crosses were made from the elite palms of six duras and five pisiferas using a factorial mating design. The progenies were transplanted in a strip-plot experimental design with three replicates. Each plot had six palms of a cross, thus making a total of 540 palms. The data on bunch yield and components were collected from 2012 to 2022. The results showed that R10/1D and R5/21P had good means and GCA for fresh fruit bunches (FFB) and bunch number (BNO) while R8/9D showed significant GCA for oil to bunch, oil yield and kernel yield. R10/5D and KA17/2P expressed high GCA for kernel to bunch and kernel yield. The cross R10/1D & times; R9/8P showed significant SCA for FFB (mean 262.97 kg palm-1 yr-1) and BNO (mean 20.81 bunches palm-1 yr-1), while R15/14D & times; KA17/2P for average bunch weight (mean 18.57 kg bunch-1). A43/9D & times; R9/8P had the best SCA for oil yield (mean 82.24 kg palm-1 yr-1), and R10/5D & times; KA17/2P for kernel yield (mean 18.15 kg palm-1 yr-1).

Importance of the work: Near-infrared (NIR) spectroscopy has great potential as a high-throughput characterizing tool, especially for improving wood qualities in jatropha breeding work. Objectives: To characterize jatropha wood qualities across various genotypes and to investigate the relationship between chemical composition and calorific value based on evaluating the chemical composition and calorific value of jatropha wood using NIR spectroscopy. Materials and Methods: Analysis was conducted on 365 wood samples from various jatropha genotypes. Neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, cellulose, hemicellulose and calorific value were all predicted using partial least squares (PLS) regression models. Results: The correlation coefficient (r) values of these models ranged from 0.65** to 0.81**, where ** indicates significance at p < 0.01, with low standard error of calibration and of prediction. In addition, there were significant effects of harvest age and reharvesting, along with notable genotypic variations in all quality parameters that the PLS models anticipated, with significant correlations between calorific value and NDF (r = 0.65**), ADF (r = 0.42**) and lignin (r = 0.91**). Main finding: The NIR spectroscopy models developed had modest predictive performance for calorific value and wood chemical components of jatropha, indicating that NIR has potential as a rapid and non-destructive tool for preliminary screening and comparative evaluation of genotypes based on wood quality.

The study examined the effect of plant spacing on yield productivity and assessed yield after pruning for jatropha. The experimental design was split-plot in a randomized complete block, including two main-plots of planting space comprised of 1 × 1.5 m (S1) and 2 × 1.5 m (S2), and 14 sub-plots were jatropha varieties of 11 interspecific hybrids crossed between jatropha and peregrina, and three jatropha varieties with four replications. The data collection was done continuously for two years and found that planting space was not significantly different in traits. In year one, S1 showed a higher value of fruit yield ha− 1 and seed yield ha− 1 than S2, while in year two, S2 displayed a higher mean, fruit weight plant− 1, and seed weight plant− 1 than S1. The inter-specific hybrid jatrophas, KUJL70 and KUJL106 gave more seed yield ha− 1 and oil content than other jatropha breeding lines.

Abstract Reducing plant spacing and pruning Jatropha hybrids may increase yield. The study aimed to investigate the effect of reduced plant spacing on yield productivity, assess pruning tolerance, and discover the relationship between yield and growth traits of Jatropha hybrids. Fourteen Jatropha hybrid genotypes evaluated yield with narrow and standard plant spacing for two years. After the first year, the Jatropha hybrid plants were hard-pruned and allowed to regrow in the second year. It found that although narrower plant spacing might reduce Jatropha hybrid growth and yield per plant, increasing plant density by reducing plant spacing could increase fruit yield, seed yield, and oil yield by up to 65.46%, 64.73%, and 63.25%, respectively, when compared to standard spacing. Furthermore, hard pruning could improve the growth of Jatropha hybrids, and pruning tolerance varied between genotypes. Under narrow spacing, KUJL110 and KUJL70 had the highest yields after pruning, and KUJL110, KUJL30, and KUJL23 had the highest pruning tolerance index (PTI). It discovered a correlation (ranging from 0.49** to 0.86**) between yield traits and plant height, canopy width, and the number of secondary branches. Additionally, a correlation (ranging from 0.51** to 0.83**) was found between oil content and shelling, as well as 100 seed weight. As a result, these traits may serve as an indirect tool for selecting Jatropha genotypes with high-yield traits.

Abstract Reducing plant spacing and pruning Jatropha hybrids may increase yield. The study aimed to investigate the effect of reduced plant spacing on yield productivity, assess pruning tolerance, and discover the relationship between yield and growth traits of Jatropha hybrids. Fourteen Jatropha hybrid genotypes evaluated yield with narrow and standard plant spacing for two years. After the first year, the Jatropha hybrid plants were hard-pruned and allowed to regrow in the second year. It found that although narrower plant spacing might reduce Jatropha hybrid growth and yield per plant, increasing plant density by reducing plant spacing could increase fruit yield, seed yield, and oil yield by up to 65.46%, 64.73%, and 63.25%, respectively, when compared to standard spacing. Furthermore, hard pruning could improve the growth of Jatropha hybrids, and pruning tolerance varied between genotypes. Under narrow spacing, KUJL110 and KUJL70 had the highest yields after pruning, and KUJL110, KUJL30, and KUJL23 had the highest pruning tolerance index (PTI). It discovered a correlation (ranging from 0.49** to 0.86**) between yield traits and plant height, canopy width, and the number of secondary branches. Additionally, a correlation (ranging from 0.51** to 0.83**) was found between oil content and shelling, as well as 100 seed weight. As a result, these traits may serve as an indirect tool for selecting Jatropha genotypes with high-yield traits.

Importance of the work: Pruning tolerance of fast-growing trees is critical for biomass energy crop cultivation.Leaf traits might be used to identify Jatropha genotypes with high biomass yields.Objectives: To evaluate the effects of pruning and performance of genotypes for leaf traits, biomass yield and wood quality in interspecific hybrids between Jatropha curcas and J. integerrima, as well as the relationships among these traits.Materials & Methods: In total, 16 Jatropha genotypes were planted in the field for 2 yr and pruned each year for biomass harvesting.Leaf traits, biomass yield, wood quality, chemical composition, and calorific value of wood were all assessed.Results: After pruning, there was no significant reduction in the overall biomass yield and leaf traits, such as leaf size, average leaf weight, specific leaf area (SLA) and SPAD chlorophyll meter reading (SCMR).Furthermore, the hemicellulose and ash contents, moisture, density and calorific value of Jatropha genotype wood were not reduced.Leaf traits, biomass yield and wood quality of a Jatropha genotype showed significant genotype variation.Interspecific hybrids KUBJL 1, KUBJL 3, KUBJL 4, KUBJL 6, KUBJL 11, and KUBJL 13 showed improved leaf traits after pruning.Pruning had no effect on the chemical composition of KUBJL 2, KUBJL 3, KUBJL 8, KUBJL 10, KUBJL 5, KUBJL 11, KUBJL 12, and KUBJL 14.Moreover, KUBJL 5, KUBJL 11, KUBJL 5, KUBJL 4, and KUBJL 2 had the highest pruning tolerance index (PTI), with fresh weight PTIs of 106.25%, 104.07%, 98.27%, and 94.57%, respectively.There were significant and highly significant correlations between biomass yield and leaf size (Pearson's coefficient [r] = -0.57[p < 0.05] to -0.75 [p < 0.01]), average leaf weight (r = -0.58[p < 0.05] to -0.74 [p < 0.01]), and SCMR (r = 0.64 [p < 0.05] to 0.79 [p < 0.01]).Wood calorific value was also related to leaf moisture content (r = -0.33 ns to -0.69 [p < 0.01]), wood moisture content (r = -0.73[p < 0.01] to -0.77 [p < 0.01]), wood density (r = 0.25 ns to 0.75 [p < 0.01]), lignin (r = 0.71 [p < 0.01] to 0.74 [p < 0.01]) and ash (r = -0.73[p < 0.01] to -0.82 [p < 0.01]).Main finding: These traits could be used to select Jatropha hybrids with high biomass yield and heat value.Furthermore, Jatropha interspecific hybrids with pruning tolerance could be selected from this study.

Importance of the work: Interspecific hybridization has the potential to increase the biomass yield of Jatropha hybrid varieties.Objectives: To assess the biomass yield and wood chemistry composition of interspecific hybrids between Jatropha curcas and J. integerrima; to evaluate the effect of pruning ages on biomass yield; and to investigate the relationships between the calorific value and chemical composition in the wood of the Jatropha hybrids.Materials & Methods: In total, 16 genotypes of interspecific hybrids, parental species and a variety commonly found in Thailand were field planted for testing; their pruned biomass yields were harvested for assessment at three different ages. Results:The pruning age of the Jatropha hybrids influenced their wood biomass yield, chemical composition and calorific value.With increasing pruning age, the hybrids tended to have higher biomass yield, lignin content and wood calorific value.Variability among genotypes was found in all the traits studied.The biomass potential of interspecific hybrids was greater than that of the parent species.The hybrids outperformed J. curcas in terms of biomass yield, moisture content, wood density, chemical composition and calorific value.The interspecific hybrid KUBJL 14 had the greatest potential for biomass production.Furthermore, the correlation coefficient (r) averaged across pruning ages indicated highly significant (p < 0.01) relationships between the calorific value of wood and its lignin (r = 0.70), lignocellulose (r = 0.74), ash (r = -0.92)and moisture (r = -0.80)contents and its density (r = 0.50).Main finding: The pruning age had positive effects on wood biomass yield, chemical composition and calorific value of Jatropha.The wood traits with a significant correlation with calorific value were identified and could be used to improve wood quality in a Jatropha hybrid breeding program.

Jatropha (Jatropha curcas L.) is a shrub that produces non-food oil and can potentially be used for biodiesel production. An interspecific cross was made between J. curcas and peregrina (J. integerrima) to increase genetic diversity. Interestingly, male sterility was observed in the F-2 population. Out of the 445 F-2 plants, five, namely, ms-1 to ms-5, exhibited male sterility, characterized by unopened and distorted stamens without pollen. The parental jatropha, peregrina, F-1 and F-2 had fertile pollen grain rates of 90.61%, 96.39%, 81.46% and 75.39%, respectively. To verify the fertility of the pistils in the male sterile plants, they were pollinated through selfing, opening and hand crossing with fertile pollen. All of the ms lines experienced seed abortion with or without fruit, except for 'ms-5', which produced seed.

Importance of the work:The consistency of biomass production is crucial for Jatropha cultivation as a short rotation woody crop for use as a biomass source.Objectives: To investigate the effect of harvest age on Jatropha hybrid growth, assess the relationship between growth traits and biomass yield and evaluate the biomass yield stability of interspecific hybrids between Jatropha curcas and J. integerrima.Materials & Methods: For 5 yr, 14 genotypes of Jatropha hybrids, were evaluated in the field, using three different harvest age rotations.Plant height, canopy width, stem and branch diameter and biomass yield were measured.Results: Harvest ages and genotypes affected Jatropha hybrid growth traits.Jatropha hybrids grew larger with age.Plant height, canopy width and stem and branch diameter were all highly correlated with biomass yield (correlation coefficient range = 0.59 [p < 0.05] to 0.94 [p < 0.01]).At the first, second, third, fourth and fifth harvests at 12 mth intervals, the Jatropha hybrids had average biomass yields of 45.91 t/ha, 40.63 t/ha, 36.46 t/ha, 42.77 t/ha and 37.29 t/ha, respectively.Although harvest frequency affected biomass yield, the yield did not substantially decrease, suggesting pruning tolerance of the Jatropha hybrids.The optimal harvest age rotations for Jatropha hybrids were intervals of 12 mth and 18 mth, due to the highest five-yearly total biomass yields of 202.79 t/ha and 221.29 t/ha, respectively.Furthermore, the KUBJL 14 genotype had the highest growth and biomass production.Main finding: The growth traits of the Jatropha hybrids could be used to assess biomass production.Jatropha hybrids have a high biomass potential and good biomass yield stability, even after multiple harvests.

Summary Jatropha curcas (physic nut), a non‐edible oilseed crop, represents one of the most promising alternative energy sources due to its high seed oil content, rapid growth and adaptability to various environments. We report ~339 Mbp draft whole genome sequence of J. curcas var. Chai Nat using both the PacBio and Illumina sequencing platforms. We identified and categorized differentially expressed genes related to biosynthesis of lipid and toxic compound among four stages of seed development. Triacylglycerol (TAG), the major component of seed storage oil, is mainly synthesized by phospholipid:diacylglycerol acyltransferase in Jatropha, and continuous high expression of homologs of oleosin over seed development contributes to accumulation of high level of oil in kernels by preventing the breakdown of TAG. A physical cluster of genes for diterpenoid biosynthetic enzymes, including casbene synthases highly responsible for a toxic compound, phorbol ester, in seed cake, was syntenically highly conserved between Jatropha and castor bean. Transcriptomic analysis of female and male flowers revealed the up‐regulation of a dozen family of TFs in female flower. Additionally, we constructed a robust species tree enabling estimation of divergence times among nine Jatropha species and five commercial crops in Malpighiales order. Our results will help researchers and breeders increase energy efficiency of this important oil seed crop by improving yield and oil content, and eliminating toxic compound in seed cake for animal feed.

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.

To analyze the karyotypes of five Jatropha species (J. cinerea, J. curcas, J. integerrima, J. multfida, and J. podagrica), fluorescence in situ hybridization (FISH) with a 35S ribosomal RNA gene (rDNA) probe was conducted. FISH analysis of mitotic metaphase chromosomes showed that the numbers of chromosomes and rDNA foci in all species analyzed were conserved, although signal intensities and their locations varied. The conserved karyotypes may be advantageous for the use of J. curcas genome data and for breeding in the progeny of interspecific crosses.

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.

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.

Next-generation sequencing is a new technique for plant genome sequencing at a large scale that is faster and cheaper than previous sequencing technologies. The present work reports the development of new polymorphic simple sequence repeat (SSR) markers in oil palm (Elaeis guineensis Jacq.) using Illumina HiSeq sequencing data. More than 39Gb (total 39,086,646,904 bases) was generated from the selected oil palm clone, D4. After de novo assembly, a total of 130,840 potential SSRs were identified. For SSR validation, 144 out of 762 SSR primer pairs were designed, including tri-nucleotide motifs, from the D4 contigs. Using 11 lines from three different clones of oil palm, 61 SSR primers revealed polymorphic alleles and high average polymorphic information content (PIC) values. Cluster analysis separated all oil palm plants into three clusters: clones A, B and C. These identified genome-wide SSR markers will enrich current genomic resources of the oil palm crop.

A high-throughput sequencing by 454 pyrose-quencing was performed on the transcriptomes of apical meristem tissue of two Jatropha curcas accessions and four jatropha-related species. J. curcas accession (acc.) CN produced 45.61 Mb data from 127,094 reads with 11, 579 contigs and 15,645 singletons, while acc. M10 produced 54.52 Mb data from 142,447 reads with 10,964 contigs and 12,069 singletons. J. integerrima acc. KL gave 20.91 Mb from 71,541 reads with 4,551 contigs and 5,144 singletons, while acc. KY gave 48.74 Mb from 149,392 reads with 8,440 contigs and 8,299 singletons. J. multifida (acc. JM) gave 66.72 Mb from 191,654 reads with 17,444 contigs and 13,965 singletons, and J. podagrica (acc. JP) gave 73.28 Mb from 165,228 reads with 14,070 contigs and 16,572 singletons. BLASTX search of all contigs revealed that 1,683 unique proteins were orthologous across all four Jatropha spp. From 432 EST-SSR primer pairs designed and tested on these six accessions, 269 markers showed polymorphism and produced a total of 862 alleles. Based on sequence alignments between J. curcas accessions with low and high phorbol esters (PEs), 20 candidate SNPs were identified in four coding sequences including one gene relating to biosynthesis pathways of PEs. These expressed sequence tag-sample sequence repeat (EST-SSR) markers and candidate single nucleotide polymorphisms (SNPs) will be useful for jatropha breeding in the future.

Genetic variation in Jatropha curcas, a prospective biodiesel plant, is limited, and interspecific hybridization needed for its genetic improvement. Progeny from interspecific crosses between J. curcas and Jatropha integerrima can be used to improve agronomic characters and to increase oil content and yield. However, these hybrids have not been characterized cytologically. The present study was aimed at the analysis of chromosome behavior during meiosis and chromosome composition of S1 plants derived from an interspecific F1 hybrid using genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH). Bivalents that formed as a result of interspecific pairing were frequently observed, suggesting the presence of homoeologous chromosomes from the two species. Almost half of microspores were derived from the reduction division; GISH analysis indicated random transmission of the parent chromosomes to microspores. Male fertility measured as pollen staining with acetocarmine was 48.4%. In contrast, GISH analysis of S1 plants revealed preferential transmission of J. curcas chromosomes. We also found segment exchange between chromosomes of the two species (interspecific translocation) by GISH and FISH analyses. Introgression of J. integerrima chromosome segments into the J. curcas genome would help to improve Jatropha cultivars for mass production.

Interspecific hybrids between Jatropha curcas × J. integerrima are potential genetic resources for jatropha improvement. However, their pollen is normally partially sterile. This study was conducted to determine pollen viability status and seed set of the hybrids. Pollen viability was estimated by staining with 1% acetocarmine. The results showed that all interspecific hybrids had pollen viability falling between their parents. The pollen viability of interspecific hybrid derived from a cross between J. curcas (high phorbol esters accession) × J. integerrima ranged from 47 % to 89 % with an average of 72 %. Similarly the viability of the hybrid J. curcas (low phorbol esters accession) × J. integerrima ranged from 44 % to 90 % with an average of 73 %. The hybrid with low pollen viability also set less seeds. This information is useful for plant breeders to select the pollen donor in interspecific breeding programs.

A total of 121 oil palm ('Eleais guineensis' Jacq.) breeding plants from three populations designated as P1, P2 and P3 were obtained from three breeding companies located in three provinces of Thailand, viz. Prachuap Khiri Khan, Kanchanaburi and Krabi, respectively. Although, these populations came from different sources, they share some common genetic backgrounds of Deli Dura and AVROS Pisifera which are the main germplasm sources of commercial oil palm breeding programs in Thailand. All plants were assessed by 96 SSR markers from which 20 of them were polymorphic giving 109 alleles with polymorphic information contents ranged from 0.45 to 0.87 for mEgCIR580 and mEgCIR787 markers, respectively. The number of alleles per locus ranged from 3 to 8 with averages of 5.05, 3.80 and 3.75 for P1, P2 and P3 and the overall average of 5.45. An analysis of molecular variance (AMOVA) gave variation among populations and individuals within populations at 33 % and 67 %, respectively. Nei's genetic distance showed that variability among populations were 0.53 (P1 vs. P3), 0.61 (P1 vs. P2) and 0.62 (P2 vs. P3). A dendrogram constructed from Jaccard's similarity coefficients of marker variation separated the oil palm trees into 4 clusters following their respective breeding companies.