Multivariate diallel analysis allows multiple gains in segregating populations for agronomic traits in Jatropha.

Jatropha is research target worldwide aimed at large-scale oil production for biodiesel and bio-kerosene. Its production potential is among 1200 and 1500 kg/ha of oil after the 4th year. This study aimed to estimate combining ability of Jatropha genotypes by multivariate diallel analysis to select parents and crosses that allow gains in important agronomic traits. We performed crosses in diallel complete genetic design (3 x 3) arranged in blocks with five replications and three plants per plot. The following traits were evaluated: plant height, stem diameter, canopy projection between rows, canopy projection on the line, number of branches, mass of hundred grains, and grain yield. Data were submitted to univariate and multivariate diallel analysis. Genotypes 107 and 190 can be used in crosses for establishing a base population of Jatropha, since it has favorable alleles for increasing the mass of hundred grains and grain yield and reducing the plant height. The cross 190 x 107 is the most promising to perform the selection of superior genotypes for the simultaneous breeding of these traits.

Path analysis and canonical correlations for indirect selection of Jatropha genotypes with higher oil yield.

Jatropha is a species with great potential for biodiesel production, and the knowledge on how the main agronomic traits are correlated will contribute to its improvement. Therefore, the objectives of this study were to estimate the genetic parameters of the traits: plant height at 12 and 40 months, canopy projection on the row at 12 and 40 months, canopy projection between the row at 12 and 40 months, number of branches at 40 months, grain yield, and oil yield; to verify the existence of phenotypic correlation between these traits; to verify the influence of the morphological traits on oil yield by means of path analysis; and to evaluate the relationship between the productive traits in Jatropha and the morphological traits measured at different ages. Sixty-seven half-sib families were evaluated using a completely randomized block design with two replications and five plants per plot. Analysis of variance was used to estimate the genetic value. Phenotypic correlations were given by the Pearson correlation between traits. For the canonical correlation analysis, two groups of traits were established: group I, consisting of traits of economic importance for the culture, and group II, consisting of morphological traits. Path analysis was carried out considering oil yield as the main dependent variable. Genetic variability was observed among Jatropha families. Productive traits can be indirectly selected via morphological traits due to the correlation between these two groups of traits. Therefore, canonical correlations and path analysis are two strategies that may be useful in Jatropha-breeding program when the objective is to select productive traits via morphological traits.

Mixed models for selection of Jatropha progenies with high adaptability and yield stability in Brazilian regions.

The aim of this study was to estimate genetic parameters via mixed models and simultaneously to select Jatropha progenies grown in three regions of Brazil that meet high adaptability and stability. From a previous phenotypic selection, three progeny tests were installed in 2008 in the municipalities of Planaltina-DF (Midwest), Nova Porteirinha-MG (Southeast), and Pelotas-RS (South). We evaluated 18 families of half-sib in a randomized block design with three replications. Genetic parameters were estimated using restricted maximum likelihood/best linear unbiased prediction. Selection was based on the harmonic mean of the relative performance of genetic values method in three strategies considering: 1) performance in each environment (with interaction effect); 2) performance in each environment (with interaction effect); and 3) simultaneous selection for grain yield, stability and adaptability. Accuracy obtained (91%) reveals excellent experimental quality and consequently safety and credibility in the selection of superior progenies for grain yield. The gain with the selection of the best five progenies was more than 20%, regardless of the selection strategy. Thus, based on the three selection strategies used in this study, the progenies 4, 11, and 3 (selected in all environments and the mean environment and by adaptability and phenotypic stability methods) are the most suitable for growing in the three regions evaluated.

Mixed models identify physic nut genotypes adapted to environments with different phosphorus availability.

The aim of this study was to screen physic nut (Jatropha curcas) genotypes that differ in their phosphorous (P) use, using mixed models. The experiment was conducted in a greenhouse located in the experimental area of the Centro de Ciências Agrárias of the Universidade Federal do Espírito Santo, in Alegre, ES, Brazil. The experiment was arranged in a randomized block design, using a 10 x 3-factorial scheme, including ten physic nut genotypes and two environments that differed in their levels of soil P availability (10 and 60 mg/dm3), each with four replications. After 100 days of cultivation, we evaluated the plant height, stem diameter, root volume, root dry matter, aerial part dry matter, total dry matter, as well as the efficiency of absorption, and use. The parameters were estimated for combined selection while considering the studied parameters: stability and adaptability for both environments were obtained using the harmonic mean of the relative performance of the predicted genotypic values. High genotype by environment interactions were observed for most physic nut traits, indicating considerable influences of P availability on the phenotypic value. The genotype Paraíso simultaneously presented high adaptability and stability for aerial part dry matter, total dry matter, and P translocation efficiency. The genotype CNPAE-C2 showed a positive response to P fertilization by increasing both the total and aerial part dry matter.

Comparison of methods used to identify superior individuals in genomic selection in plant breeding.

The aim of this study was to evaluate different methods used in genomic selection, and to verify those that select a higher proportion of individuals with superior genotypes. Thus, F2 populations of different sizes were simulated (100, 200, 500, and 1000 individuals) with 10 replications each. These consisted of 10 linkage groups (LG) of 100 cM each, containing 100 equally spaced markers per linkage group, of which 200 controlled the characteristics, defined as the 20 initials of each LG. Genetic and phenotypic values were simulated assuming binomial distribution of effects for each LG, and the absence of dominance. For phenotypic values, heritabilities of 20, 50, and 80% were considered. To compare methodologies, the analysis processing time, coefficient of coincidence (selection of 5, 10, and 20% of superior individuals), and Spearman correlation between true genetic values, and the genomic values predicted by each methodology were determined. Considering the processing time, the three methodologies were statistically different, rrBLUP was the fastest, and Bayesian LASSO was the slowest. Spearman correlation revealed that the rrBLUP and GBLUP methodologies were equivalent, and Bayesian LASSO provided the lowest correlation values. Similar results were obtained in coincidence variables among the individuals selected, in which Bayesian LASSO differed statistically and presented a lower value than the other methodologies. Therefore, for the scenarios evaluated, rrBLUP is the best methodology for the selection of genetically superior individuals.

Development of novel simple sequence repeat markers from a genomic sequence survey database and their application for diversity assessment in Jatropha curcas germplasm from Guatemala.

The last few years have seen a significant increase in the number of large-scale sequencing projects generating whole genome databases. These sequence databases can be surveyed (genome sequence survey) for tandem repeats as an alternative means to develop microsatellites for monitoring and selecting natural populations and cultivars of Jatropha curcas. A total of 100 tandem repeats were revealed from mining 368 genomic surveyed sequences available in the Kazusa DNA Research Institute database. Twenty microsatellite sequences were successfully amplified, resulting in repeatable and scorable polymerase chain reaction products. Genotyping of J. curcas accessions from the Guatemalan population revealed 18 polymorphic loci. The average number of alleles per locus was 6.9, and allelic sizes ranged from 94 to 299 bp. Expected and observed heterozygosities ranged from 0.118 to 0.906 and from 0.082 to 0.794, respectively. Polymorphic information content values ranged from 0.114 (JcSSR-34) to 0.886 (JcSSR-33) with an average of 0.627. Analysis with Micro-Checker indicated few null alleles for locus JcSSR-37 in Guatemalan populations, which may be a possible cause of its deviation from Hardy-Weinberg equilibrium, even after Bonferroni's correction. No loci showed significant linkage disequilibrium. These microsatellite loci are expected to be valuable molecular markers in J. curcas because they show high levels of polymorphism and heterozygosity.

Methods to assess the viability of cryopreserved Jatropha curcas L. seed germplasm / Métodos para avaliar a viabilidade de germoplasma semente criopreservado de Jatropha curcas L

ABSTRACT Jatropha curcas L. is a plant species with many potential applications, especially medicinal uses (hypoglycemic, anti-inflammatory, haemostatic, healing, anti-tumor). The objective of this study was to test germination in moist paper rolls for whole seeds and in vitro for excised embryonic axes, in an attempt to identify the best method to assess the quality of J. curcas seed germplasm, cryopreserved with different water contents. The experimental sample with a 6.2% moisture content (MC) was divided in subsamples which were hydrated and dehydrated for 0 (control), 4, 8, 11 and 24h. The initial germination percentages were 63% for whole seeds and 81% for excised embryonic axes. After exposure to liquid nitrogen (LN), germination percentages were 48% (whole seeds) and 57% (excised embryonic axes). There was no significant difference between germination percentages in embryonic excised from seeds subjected or not subjected to freezing, with different MC. In contrast, there was a reduction of the whole seed germination percentage when exposed to LN (contrast = 0.17, standard error = 0.04, t = 4.09, p = 0.001) and not for the hydration and dehydration treatments. The methodology based on in vitro cultures of the embryonic axis isolated from seeds stored in LN with distinct MC values was more efficient than the standard germination test to evaluate the viability of J. curcas seeds before and after LN storage.

RESUMO Jatropha curcas L., é uma espécie com várias aplicações potenciais, principalmente para usos medicinais (hipoglicemina, anti-inflamatório, homeostático, cicatrizante, antitumoral). O objetivo deste estudo foi testar a germinação em rolo de papel para sementes inteiras e in vitro para eixos embrionários excisados visando identificar o melhor método para avaliar a qualidade de germoplasma semente de J. curcas, criopreservado com diferentes teores de água. A amostra experimental com 6,2% de teor de água foi dividida em subamostras que foram hidratadas e desidratadas por 0 (controle), 4, 8, 11 e 24 h. Os percentuais de germinação inicial foram de 63% para sementes inteiras e de 81% para eixos embrionários excisados. Após exposição ao nitrogênio líquido (NL) os percentuais de germinação foram de 48% (sementes inteiras) e 57% (eixos embrionários). Não houve diferença significativa entre os percentuais de germinação de eixos embrionários excisados de sementes com diferentes umidades e submetidas ou não ao congelamento. Em contraste, houve redução de percentuais de germinação das sementes inteiras expostas ao NL (contraste = 0.17, erro padrão = 0.04, t = 4.09, p = 0.001), mas não aos tratamentos de hidratação e desidratação. A metodologia baseada em cultura de eixos embrionários in vitro isolados de sementes armazenadas em NL, com distintos teores de água foi mais eficiente que a germinação padrão para avaliar a viabilidade de sementes J. curcas antes e após a armazenamento em NL.