Estimação de parâmetros genéticos e de diversidade em pinhão-manso (Jatropha Curcas L.) quanto à arquitetura de plantas com variáveis obtidas via análise de imagens digitais

Abstract

The search for renewable energy sources such as biodiesel and ethanol, is a growing trend in Brazil and in the world due to lower environmental impacts. Among the plant species available to search, highlight the physic nut (Jatropha curcas L.), that it is a perennial species, deciduous and with great potential for biodiesel production due to their production characteristics and quality of oil . However, to date there is no available cultivars for planting, so the need for basic and applied research. Therefore, it is important to know the behavior of genotypes and several variables estimated in the culture, among these quotes to the related plant architecture. The objective of this study was a detailed study of the characteristics related to plant architecture, in order to know the diversity within and among 10 families of jatropha half brothers belonging to the Germplasm Collection UFRRJ through digital analysis images. The treatments (families) were arranged in a randomized design, with 15 replications (plants). Made to capture images, in the same measuring scale at the time the plants were in his deciduous period and subsequently through ImageJ software, the images were processed. It estimated the following variables related to plant architecture: plant height (ALT), stem diameter (DBC), crown diameter (DCO), number of branches to 50 cm (NR50), opening angle Canopy (AAB), the total number of forks in the plant (NBI), the average height of the forks (MAB), number of branches above (NRAcmab) and below (NRAbmab) of MAB, the sum length of the branches (SCR), area of the plant (APL). It was estimated also in the field, the number of fruits (NFR) and seeds (NSE), average seed weight (PMS) and grain yield per plant (PGP), and these were used only in correlation analysis with variables related to plant architecture. From these data were carried out analysis of variance, correlation, estimation of genetic parameters and analysis of diversity. Only the variable number of branches to 50 cm (NR50) was not statistically different between the evaluated progenies. ALT variables, DCO, NBI, NRAcmab, NRAbmab, SCR and APL had greater genetic influence at the expense of environmental, justifying the selection of these characteristics. The grain yield per plant (PGP) had low correlation with all variables, with SCR and NRAcmab showed the highest values respectively 0.24 and 0.20. The genetic diversity was estimated between families median ranging between 0.4 and 0.6. The diversity within families was medium to low with estimates families with more than 0.6 and less than 0.4, respectively, to the families 858, 355 and 869, and 346, 383 and 872. The number of bifurcations (NBI ), the flat area of the plant (APL) and the sum of the length of the branches (SCR) were the most important features in the estimation of diversity in this study, with the contribution of respectively 30.55%, 22.29% and 10, 65%. The family 872 showed favorable aspects related to plant architecture, such as the high average number of bifurcations (NBI) and, in general, the greatest genetic distance between the other families. Therefore, prior assessment for evidence of productive potential, family genotypes 872 may be involved in crosses when you want to explore heterosis culture.