GENETIC DISSIMILARITY AMONG THE PHYSIOCHEMICAL CHARACTERISTICS OF FRUIT FROM PEPPER ACCESSIONS

The objective was to evaluate the genetic variability among pepper accessions al the physical and chemical characteristics of fruit. Pepper accesses are from the Germplasm Bank at the Federal University of Uberlandia Monte Carmelo Campus (Universidade Federal de Uberlândia-UFU, Campus Monte Carmelo, MG, Brazil). The experiment was conducted from November 2013 to March 2014 at UFU’s Experimental Station on the Monte Carmelo campus, MG, Brazil. The statistical design consisted of randomized blocks with 47 treatments and four replications. Multivariate analyzes were performed for quantitative traits in 47 pepper access by principal component analysis. Means were compared by Scott-Knott test (α = 0.05). Mature fruits were collected 120 days after transplant and used to determine titratable acidity (TA), total soluble solids (SS), pH and SS/TA. There was genetic variability among accessions. The 47 accessions showed high soluble solids content of 9.08 ° Brix, acidity of 0.22, pH of 5.50 and an SS/TA ratio of 33.8. This last characteristic is of great importance in the food processing industry. UFU accession 28 has high levels of SS and TA and is therefore a candidate for Pepper breeding programs that target the needs of the food processing industry.


INTRODUCTION
Peppers (Capsicum spp., Solanaecae family) are one of the most important vegetable crops in Brazil, especially in economic terms (Reifschneider 2000, Echer et al. 2002, Ribeiro et al. 2008).Special effort should be given to preserving some pepper species due to their national origin and distribution throughout Brazil (Reifschneider 2000).Moreover, genetic erosion within this species underlines the need for research that aims to preserve and characterize this national genetic resource.
Agricultural expansion and indiscriminate land use in Brazil may lead to the extinction of many wild species that include members of the Capsicum genus (Reifschneider 2000, Ribeiro et al 2008).One strategy for preserving genetic resources that are at risk of extinction is the creation of public, private, national and international germplasm banks.Hence, in 2013, the Germplasm Bank of Capsicum spp. was created at the Federal University of Uberlândia-UFU, Monte Carmelo Campus that currently contains more than 250 registered accessions.
Plant breeders have mostly focused on obtaining cultivars that are resistant to pests and diseases.Recently, however, the food processing industry has shown increasing interest in breeding programs that focus on the physical and chemical characteristics of pepper fruits (Ribeiro et al. 2008) that may significantly strengthen the supply chain.Registered pepper cultivars are scarce and no varieties are available for direct use by farmers that are specifically suitable for processing, especially regarding characteristics such as total soluble solids, titratable acidity, the SS/TA ratio and pH.Detailed characterization of genetic diversity in this genus may encourage future breeding programs (Geleta et al. 2005, Neitzke et al. 2010, Ferrão et al. 2011, Faria et al. 2012).
Its was evaluated genetic variability in the physical and chemical characteristics of fruit from various pepper accessions in the Capsicum Germplasm Bank at the Federal University of Uberlândia-UFU.

MATERIAL AND METHODS
Forty-seven accessions were evaluated from the Germplasm Bank of Capsicum spp. at the Federal University of Uberlândia-UFU, Monte Carmelo Campus, MG, Brazil.Currently, the bank has 250 accessions that have been acquired through donation, collection and purchase at farmers' The trial was conducted at the Horticultural Experiment Station, UFU (Estação Experimental de Hortaliças da UFU) (altitude 873 m, 18º42'43,19"S, 47º29'55,8"W, humid temperate climate with hot summers and dry winters).Sowing took place on November 21, 2013 in 200-cell polystyrene trays filled with a commercial, coconut-fiber based substrate.The trays were kept in a gable-roofed greenhouse (7 x 4 m) with a ceiling height of 3 meters and covered by a transparent 150-micron polyethylene film activated against ultraviolet rays.The seedlings were transplanted 60 days after sowing (after the appearance of 4 to 6 sets of leaves).Twenty seedlings of each accession were transplanted into individual rows (spaced 1.0 x 0.7 m) in each plot for a total of 1316 m 2 with 14 m 2 in each experimental unit.
Fully mature fruits were harvested 120 days after transplant for physiochemical characterization.These samples were then used to determine titratable acidity (TA), total soluble solids (TSS), pH and SS/TA.Soluble solids (SS) were determined using a digital refractometer according to the AOAC methodology ( 2002) and expressed as °Brix.Titratable acidity was determined by diluting 1 g of pulp in 50 mL of distilled water and then titrating with a NaOH solution (0.1 N).These results were expressed as a percentage of citric acid (Ial 1985).After processing, pH was measured directly in the pulp using a potentiometer (Mettler DL 12 model) calibrated with pH 4 and 7 buffers AOAC (2002).
The statistical design was randomized blocks (RBD) with 47 treatments (accessions) and four repetitions.
Y ij = µ + b j + t i + e ij where: Y ij -observation of the i-th genotype in the j-th block; µ-fixed effect of the general average; b j -random effect of the j-th block; t i -fixed effect of the i-th genotype (treatments); e ij -mean experimental error.Means were submitted to analysis of variance, which consisted of comparing the sum of mean squares by the F test (α = 0.05).A Scott-Knott test (α = 0.05) was used to compare the means of soluble solids, titratable acidity and the SS/TA ratio.In order to unite information from these variables, multivariate analysis was performed through principle components using the Genes software (Cruz 2008).

RESULTS AND DISCUSSION
There was a significant difference (p > 0.05) among the 47 accessions (especially UFU 28) regarding soluble solids (SS), titratable acidity and the SS/TA ratio (Table 2).Means followed by the same letter within a column do not differ by the Scott-Knott test at 5% probability.
Significant differences were found among SS values.For example, UFU 28 stood out with 12.623 Brix, suggesting this variety's potential for applications in the food processing industry.UFU 06 and UFU 14 showed high SS values (11.813 and 12.088 °Brix, respectively), indicating their potential for breeding programs.In contrast, accession UFU 16 had a low SS value (4.0 ° Brix), which might indicate potential for crosses with other varieties in order to increase SS.The magnitude between the highest and lowest SS values among all evaluated accessions (UFU 28 versus 16 UFU) was a highly divergent 68.31%.The SS values obtained in the present study were higher than those found by Lannes et al. (2007), which varied from 6 to 10 °Brix.A high level of soluble solids in vegetable crops is important to the food processing industry because it indicates higher final yield (REGO et al., 2009).
Among the 47 accessions evaluated, TA varied significantly from 0.444 to 0.0747% (UFU 28 and UFU 44, respectively) for a total oscillation of 83.18%.UFU 30 and UFU 28 (0.424 and 0.444%, respectively) were the most prominent.A high TA level in fruit is important because it is reflected in preservation and deterioration (OLIVEIRA et al. 1999).The high values found in UFU 30 and UFU 28 were slightly lower than those found by Crisóstomo et al. (2008) in the fruit of the Tabasco cultivar (0.48%).In contrast, the TA values of UFU 30 and UFU 28 were higher than those found by Valverde (2011) (0.03 %).
The SS/TA ratio varied among the accessions evaluated.UFU 44 had the highest ratio at 107.884 (Table 2).The SS/TA results found in the current study were higher than those found by Crisóstomo et al. (2008), which averaged 47.93.The ratio between total soluble solids and titratable acidity is related to the balance between sugar and acid and therefore is an important indicator of flavor.
The pH levels varied little among progenies with a low of 5.13 and a high of 5.57 (Table 2) for a total variation of 7.89%.These pH values were higher than those found by Crisóstomo et al. (2008), which averaged 4.75 in fruit of the cultivar "Tabasco" grown in the Brazilian state of Ceará.Valverde (2011) found a slightly acid average value (5.48) for the malgueta pepper in natura.This value was similar to that found in the present study.pH is an important indicator of the potential for and rapidity of deterioration from the growth of hazardous microorganisms.
The 47 accessions in the current study showed an average soluble solids level of 9.08 °Brix, titratable acidity of 0.22, pH of 5.50 and SS/TA of 33.83, which is of great importance to the food processing industry.UFU 28 had high SS and TA values, which suggest that this accession has potential for pepper breeding programs that target the needs of industry.
Principal component analysis (Figure 1) reinforced the results of the means test (Table 2) that showed the genetic variability of the accessions tested.Four distinct groups are evident (Figure 1).The first group consists of only UFU 44, which had the lowest TA value (0.0747%) and the highest SS/TA ratio (107.884%) of all the tested accessions (Table 2).The second group consisted of UFU 2, UFU 6, UFU 14, and UFU 28.The third group was represented by UFU 1, UFU 3, UFU 7, UFU 8, UFU  The efficiency of using principal component analysis with accessions of the Capsicum genus has been confirmed by various authors and is widely used (MONTEIRO et al. 2010, NEITZKE et al. 2010, FERRÃO et al. 2011, FARIA et al. 2012).In the present study it was also possible to efficiently detect divergence among accessions.The genetic dissimilarity revealed among the accessions could be further explored by obtaining homozygous lines and subsequent hybrid combinations targeting heterosis (MALUF, 2001;RIBEIRO et al. 2008, RÊGO et al. 2009).
Its was determined that the capsicum germplasm bank at the Federal University of Uberlandia (Universidade Federal de Uberlândia) has sufficient genetic diversity for exploration in breeding programs that target the needs of the food processing industry.

CONCLUSION
There was genetic variability among accessions performed.The genetic dissimilarity among the accessions evaluated in the current study indicates potential for pepper breeding programs, especially those that target the needs of the food processing industry.sólidos solúveis de 9,08 ° Brix, acidez de 0,22, pH de 5,50 e uma relação SS / AT de 33,8.Esta última característica é de grande importância na indústria de processamento de alimentos.O acesso UFU 28 revelou níveis elevados de SS e AT se destacando entre os demais.Os acessos que destacaram são promissores para fomentar futuros programas de melhoramento genético de pimenta com boas características para indústria de processamento.

Table 1 .
All accessions are held at the Laboratory of Seed and Genetic Resource Analysis, UFU (LAGEN, Laboratory of Genetic Resources/UFU).This genetic material includes part of the pepper biodiversity in the Alto Paranaíba and Triângulo Mineiro regions of Minas Gerais state that are home to hundreds of small-scale pepper producers.Description of some of the peppers in the Germplasm Bank of Capsicum spp at the Federal University Biosci.J., Uberlândia, v. 32, n. 4, p. 978-985, July/Aug.2016 markets.

Table 2 .
Physiochemical characterization of pepper accessions from the Capsicum spp.Germplasm Bank at the Federal University of Uberlandia (Universidade Federal de Uberlândia-UFU) -Monte Carmelo