Phenotypic diversity in physic nut (Jatropha curcas L.) in vivo germplasm bank for superior parent selection

Abstract

Jatropha curcas is an interesting alternative for biodiesel production due to the high oil content in its seeds, its ability to grow in a wide range of climate and soil conditions as well as low cost of production. However, the species is considered to be in domestication and there are no defined cultivars. Therefore, it is extremely important to understand the genetic diversity of the species for selection and characterization of promising genotypes to initiate breeding programs. The objective of this study is to evaluate the phenotypic diversity of physic nut in order to select the most divergent and superior genotypes to compose future breeding programs, using multivariate analysis. Eleven agronomic characters were evaluated in 165 J. curcas genotypes from the in vivo germplasm bank, which were: Plant height, stem diameter, number of primary branches, fruit length, width, weight and shape, seed length, width and weight plus the oil content. The data were analyzed by principal component analysis (PCA), cluster analysis by Ward and k-means methods. The character fruit shape was removed from the multivariate analysis as the only one with qualitative character. The PCA resulted in 4 main components (PC), which explained 71.62% of total variance. The characters selected in PC1 were seed weight, fruit width, fruit length and fruit weight. There were 22 promising genotypes highlighted, with potential to be exploited in breeding programs. Cluster analysis by Ward and k-means methods generated 9 groups influenced by all analyzed characters, of which five groups of genotypes had advantageous characters. Regarding fruit shape, 13 genotypes had an ellipsoid lanceolate shape and the others had an ellipsoid spherical shape. Multivariate analyses allowed genotype characterization, indicating good strategies used for the selection in genetic breeding programs.

Progresso Genético E Seleção Precoce Em Genótipos De Pinhão-Manso Em Fase Juvenil

“…O pinhão-manso (Jatropha curcas L.) é uma espécie da família Euphorbiaceae que responde bem as condições ambientais das regiões tropicais e subtropicais do planeta (AYIZANNON et al, 2017). A oleagionosa apresenta ampla diversidade de uso, mas se destaca no cenário energético global por ser fonte alternativa de combustíveis fósseis, sendo destinada à produção de biodiesel (MORAES et al, 2017).…”

“…Variações genéticas foram observadas em acessos brasileiros de pinhão-manso e contribuíram na caracterização de germoplasma e identificação de genótipos com caracteres favoráveis de J. curcas (DÍAS et al, 2017;SOUSA et al, 2019). Identificar a variabilidade genética do germoplasma é outra etapa importante nos programas de melhoramento da espécie com objetivo de realizar a seleção de genótipos (MORAES et al, 2017) para compor genitores em futuros cruzamentos direcionados.…”

ASSIGNING MORPHOLOGICAL TRAITS AS DESCRIPTORS FOR DIFFERENTIATION BETWEEN Jatropha curcas ACCESSIONS

“…The morphological characterization of J. curcas was a first step in its domestication and genetic improvement (Prado et al, 2017). It has allowed to make varietal guides (Achten et al, 2010;Montes and Melchinger, 2016;Sunil et al, 2013a;Yi et al, 2014) that can serve to improve the exchange of information between collections from different regions and accelerate the process of domestication of J. curcas from a wild crop to an agronomic crop (Prado et al, 2017). However, most of the traits described in the guides do not have a pure line that could be used as reference to determine their importance for the differentiation of varieties.…”