PROGRESSO GENÉTICO E SELEÇÃO PRECOCE EM GENÓTIPOS DE PINHÃO-MANSO EM FASE JUVENIL

O pinhão manso (Jatropha curcas L.) é uma euforbiácea utilizada na produção de biodiesel. A espécie possui base genética estreita o que dificulta o processo de lançamento de cultivares. Caracterizar precocemente os genótipos constitui etapa importante no melhoramento da cultura. Objetivou-se com este estudo realizar uma seleção precoce em caracteres morfoagronômicos, predizer o progresso genético de tais caracteres e indicar genitores potenciais para obtenção de progênies. O delineamento experimental utilizado foi o de blocos casualizados com 26 tratamentos e três repetições. As variáveis morfoagronômicas foram analisadas via modelos mistos e o progresso genético obtido pela seleção direta, indireta e índices de seleção. A dissimilaridade genética foi determinada pela distância de Mahalanobis, com agrupamento hierárquico UPGMA e coeficiente de correlação cofenética adquirido de 1.000 permutações. As estimativas demonstraram variabilidade genética, com identificação de genótipos juvenis promissores. Os genótipos JCCE034, JCCE014 e JCCE103 apresentam melhores progressos genéticos e os genótipos JCCE036 e JCCE86 apresentam maiores divergências genéticas, formando clusters individuais. Os genótipos de pinhão-manso são promissores na seleção precoce e possuem satisfatórios ganhos com a seleção para os caracteres avaliados. Os genótipos apresentam boa capacidade para compor grupos de genitores em cruzamentos direcionados, constituindo populações-base no melhoramento de J. curcas. Palavras-chave: Jatropha curcas; diversidade genética; ganhos com a seleção; índices de seleção. Genetic progress and early selection of juvenile physic nut genotypes ABSTRACT: Physic nut (Jatropha curcas L.) is a euphorbia used in the production of biodiesel. The species has a narrow genetic base which the process of launching cultivars is difficult. Early characterization of the genotypes is an important step in crop breending. The aims of this study were to perform an early selection in morpho-agronomic traits, to predict the genetic progress of such traits and to indicate potential parents for progeny development. The experimental design used for the randomized blocks with 26 treatments and three replications. The morpho-agronomic traits were analyzed via mix models and the genetic progress added by direct, indirect selection and selection indexes. The genetic dissimilarity was provided by the Mahalanobis distance, with UPGMA hierarchical grouping and co-phenetic correlation coefficient acquired from 1,000 permutations. The indicators demonstrated genetic variability, with the identification of promising juvenile genotypes. The genotypes JCCE034, JCCE014 and JCCE103 show better genetic progress and the genotypes JCCE036 and JCCE86 show greater genetic divergences, forming individual clusters. J. curcas genotypes are promising in early selection and have satisfactory genetics gains for the traits. The genotypes have a good ability to compose groups of parents in targeted crosses, constituting base populations in the improvement of J. curcas. Keywords: Jatropha curcas; genetic diversity; selection gains; selection indexes.

Growth and mineral composition of Jatropha curcasL.under phosphate fertilization and soil compaction

The present work aimed to quantify the growth of young physic nut plants submitted to variations in phosphorus (P) and specific masses of a Red Yellow Latosol soil. Previously, a soil sample was collected in the 20 to 40 cm layer, making sure in the laboratory the low availability of P - 1.4 mg dm-3 - to apply the treatments of interest. Doses of 0, 106 and 318 mg dm-3 of P were applied, using the simple superphosphate source; and the soils were compacted until reaching specific soil masses equal to 1.53; 1.72 and 1.91 kg dm-3, in a complete factorial scheme, totaling nine treatments. The cultivation was carried out in pots and the dry biomass of the aerial part of the physic nut and its parts fractionated in the stem, leaves adhered to the stem and senescent leaves were determined. The contents of P, K, Ca, Mg, Cu, Fe, Mn and Zn were determined, and from the dry mass accumulation data, the contents of these minerals in the plants were quantified. The statistical analysis of the data consisted of analysis of variance, Tukey average test and regression analysis. In general, the mineral composition characteristics of the plants showed a more pronounced response to phosphate fertilization compared to the tested physical compression. The maximum estimated mineral content in physic nut plants was 51.78 mg of P; 463.37 mg of K; 201.84 mg of Ca; 124.18 mg of Mg; 76.17 µg of Cu; 4,254.07 µg of Fe; 18,787.15 µg of Mn and 769,97 µg of Zn.

Genetic variability and genetic progress in seed traits in breeding the physic nut

Determining the chemical composition of seeds of the physic nut (Jatropha curcas L.) is of great importance for the species due to the oil content of the seeds (the principal trait of interest). Identifying promising genotypes with selectable seed traits is one of the strategies adopted in breeding the physic nut in order to increase the yield and quality of the oil. Therefore, the aim of this study was to determine the chemical composition of seed traits in ten half-sibling progeny of the physic nut, and to identify which progeny have good genetic performance for transmission to the offspring. The experimental design was completely randomised, with ten treatments and four replications. The treatments were represented by seeds from half-sibling progeny in which the carbohydrate, protein and lipid content, and the composition of the fatty acids were evaluated. The genetic parameters and the gains from their selection were predicted for the principal seed traits using mixed-model analysis, including REML (restricted maximum likelihood) and BLUP (best linear unbiased prediction). The physic-nut seeds showed an average dry matter (DM) concentration of 60 mg g-1 carbohydrates, 42 mg g-1 protein and 142 mg g-1 total lipids. Unsaturated fatty acids represented more than 85% of the total fatty acid composition, with the oil classified as oleic-linoleic. Considering the predictions of the genetic parameters, the lipid traits can be selected for the purpose of breeding, resulting in genetic progress in the yield and quality of physic-nut oil.

DETEKSI VARIASI SOMAKLONAL PLANLET Jatropha curcas Linn. HASIL REGENERASI EMBRIO SOMATIK DENGAN MARKA MOLEKULAR ISSR

Physic nut (Jatropha curcas Linn.) has the potential as a source of sustainable biofuels. Somatic embryo proliferation of J. curcas may cause somaclonal variations. This research aimed to investigate somaclonal variations of J. curcas somatic embryo derived-plantlet using ISSR markers. Somatic embryos of J. curcas at the globular phase were cultured on liquid MS medium supplemented with 0, 0.5, 1.0, 1.5, and 2.0 mg L-1 of 2,4-D. Parameter observed were embryos weight, embryos volume, colour, and size of embryos. After proliferation, the embryos were cultured on a germination medium until the cotyledonary phase. The results showed that proliferation of J. curcas somatic embryos was optimal, with the highest weight and volume, at MS medium added with 1 mg L-1 2,4-D.

Rhizobacteria and Arbuscular Mycorrhizal Fungi of Oil Crops (Physic Nut and Sacha Inchi): A Cultivable-Based Assessment for Abundance, Diversity, and Plant Growth-Promoting Potentials

Nowadays, oil crops are very attractive both for human consumption and biodiesel production; however, little is known about their commensal rhizosphere microbes. In this study, rhizosphere samples were collected from physic nut and sacha inchi plants grown in several areas of Thailand. Rhizobacteria, cultivable in nitrogen-free media, and arbuscular mycorrhizal (AM) fungi were isolated and examined for abundance, diversity, and plant growth-promoting activities (indole-3-acetic acid (IAA) and siderophore production, nitrogen fixation, and phosphate solubilization). Results showed that only the AM spore amount was affected by plant species and soil features. Considering rhizobacterial diversity, two classes—Alphaproteobacteria (Ensifer sp. and Agrobacterium sp.) and Gammaproteobacteria (Raoultella sp. and Pseudomonas spp.)—were identified in physic nut rhizosphere, and three classes; Actinobacteria (Microbacterium sp.), Betaproteobacteria (Burkholderia sp.) and Gammaproteobacteria (Pantoea sp.) were identified in the sacha inchi rhizosphere. Considering AM fungal diversity, four genera were identified (Acaulospora, Claroideoglomus, Glomus, and Funneliformis) in sacha inchi rhizospheres and two genera (Acaulospora and Glomus) in physic nut rhizospheres. The rhizobacteria with the highest IAA production and AM spores with the highest root-colonizing ability were identified, and the best ones (Ensifer sp. CM1-RB003 and Acaulospora sp. CM2-AMA3 for physic nut, and Pantoea sp. CR1-RB056 and Funneliformis sp. CR2-AMF1 for sacha inchi) were evaluated in pot experiments alone and in a consortium in comparison with a non-inoculated control. The microbial treatments increased the length and the diameter of stems and the chlorophyll content in both the crops. CM1-RB003 and CR1-RB056 also increased the number of leaves in sacha inchi. Interestingly, in physic nut, the consortium increased AM fungal root colonization and the numbers of offspring AM spores in comparison with those observed in sacha inchi. Our findings proved that AM fungal abundance and diversity likely rely on plant species and soil features. In addition, pot experiments showed that rhizosphere microorganisms were the key players in the development and growth of physic nut and sacha inchi.