Maize karyotype variability has been extensively investigated. The identification of maize somatic and pachytene chromosomes has improved with the development of fluorescence in situ hybridization (FISH) using tandemly repeated DNA sequences as probes. We identified the somatic chromosomes of sister inbred lines that were derived from a tropical flint maize population (Jac Duro [JD]), and hybrids between them, using FISH probes for the 180-bp knob repeat, centromeric satellite (CentC), centromeric satellite 4 (Cent4), subtelomeric clone 4-12-1, 5S ribosomal DNA and nucleolus organizing region DNA sequences. The observations were integrated with data based on C-banded mitotic metaphases and conventional analysis of pachytene chromosomes. Heterochromatic knobs visible at pachynema were coincident with C-bands and 180-bp FISH signals on somatic chromosomes, and most of them were large. Variation in the presence of some knobs was observed among lines. Small 180-bp knob signals were invariant on the short arms of chromosomes 1, 6, and 9. The subtelomeric 4-12-1 signal was also invariant and useful for identifying some chromosomes. The centromere location of chromosomes 2 and 4 differed from previous reports on standard maize lines. Somatic chromosomes of a JD line and the commonly used KYS line were compared by FISH in a hybrid of these lines. The pairing behavior of chromosomes 2 and 4 at pachytene stage in this hybrid was investigated using FISH with chromosome-specific probes. The homologues were fully synapsed, including the 5S rDNA and CentC sites on chromosome 2, and Cent4 and subtelomeric 4-12-1 sites on chromosome 4. This suggests that homologous chromosomes could pair through differential degrees of chromatin packaging in homologous arms differing in size. The results contribute to current knowledge of maize global diversity and also raise questions concerning the meiotic pairing of homologous chromosomes possibly differing in their amounts of repetitive DNA.

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Cariótipos representativos das varieda des 2001ca), 2013Cb) e 2014cc) de C.chínense e 4000cd) e 4002ce) de C.frutescens 6 Ideogramas das variedades 2001ca), 2013cb) e 2014cc) de Capsicum chinense 91 7 e 4000cd) e 4002ce) de C.frutescens. 92 Cariótipos representativos das varieda-8 9 des 431(a), 435(b), 530(c), 2042(d) e C. b. L. (e) de Capsícum baccatum. Ideogramas das variedades 431(a), 435(b), 530(c), 2042(d) e C.b.L.(e) de Capsícum baccat; um. .. . Cariótipos representativos das espécies selvagens C.fle.xuosum(a),C.chacoense(b),. 96 97 C.parvifolium(e), C.praetermissum (d). 104 10 Ideogramas das espécies selvagens C.fle.xuosum (a), C.parvifolium(e) e C. chacoense (b) , C.praetermissum(d). . 105 11 Metáfase mitótica corada pelo método de bandamente C na variedade 2013 de C.chinense,evidenciando bandas telomé ricas e dois grandes blocos correspon dentes ao satélites.. . 128

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Plants endue a key role against illnesses caused by oxidative stress. These attributes are frequently associated with polyphenolic compounds. However, presence and concentration of secondary metabolites are affected by abiotic factors. The in vitro culture techniques can solve these drawbacks. Peppers can be a suitable alternative to obtain polyphenols. Aiming to optimise the callus culture stage from Capsicum baccatum to produce polyphenols, this work evaluated systemically the effects of the explant's origin (root, hypocotyl and cotyledon), growth hormone type (2,4-dichlorophenoxyacetic acid (2,4-D), benzylaminopurine (BAP) and a combination of 2,4-D/BAP at five-to-one ratio) and concentration (0.023-10.000 mg L) on callus culture efficiency parameters using a multilevel factorial design. The root explant in combination with BAP at 1.138 mg L ensured the optimal values of the assessed responses; ​callus mass (225.03 mg), antioxidant activity (35.95%), total phenols (11.48 mg of GAE/g DE) and flavonoids (15.92 mg of RU/g DE) production.

The Capsicum genus comprises hundreds of varieties with fruits that differ widely in shape, size, color, and flavor. The Brazilian cuisine consumes Capsicum baccatum L. (pepper) extensively and few reports about chemical composition and biological properties about this pepper were published. The present study determined four factors numeric effects on germination in vitro of this specie, among them, the solution type for osmotic conditioning (water and 1% KNO3 aqueous solution), germination medium (agar and agar + gibberellic acid at 1.88 mgL -1 ), post-seeding time (15 and 30 days) and two genotypes (Pitanga and Cambuci) on two germination parameters (germination and cotyledon emerging rates), as first step for establishing a cell suspension culture to produce secondary metabolites. The methodology was a two-level full factorial experimental design (2 4 ). The results allowed polynomial equations definition which describes the germination phenomena as a function of the four factors under study. The genotype responses to osmotic conditioning and germination medium were different. The optimal combination of treatments for in vitro germination and development of seedlings for Pitanga and Cambuci was water + agar and water + agar-GA3, respectively.

This work aimed to optimize statistically the culture medium composition for cell plant suspension culture using as a model Capsicum baccatum L. var. pendulum cells. The cell growth was maximized as well as the secondary metabolite yields with antioxidant activity, which could find applications in pharmaceutical and food industries. A Box-Behnken statistical design was utilized to optimize the basal Murashige and Skoog medium, which is widely used in plant cell culture. Three relevant ingredients, saccharose (A, 15-45 g L −1), KH 2 PO 4 (B, 0.085-0.255 g L −1) and KNO 3 (C, 0.95-2.85 g L −1) were considered. The cell growth index as well as antioxidant activity, total phenolic compounds and flavonoids from dry extracts (DE) derived of cell cultures, were determined. Growth index (GI) and flavonoids content (F) were sensitive to the changes in nutrient composition in culture medium, and they were modeled statistically according to modified quadratic (GI = 1.76 + 0.59A − 0.32B − 0.42AC) and two-factor interaction (F(mg of rutin∕g DE) = 0.88 + 0.35AC − 0.29BC) models, respectively. Antioxidant activity and total polyphenols were independent of the nutrient concentrations within the range under study. The optimized culture medium composition was defined for two approaches: maximization of the cell growth (45 g L −1 saccharose, 0.09 g L −1 KH 2 PO 4 , 0.95 g L −1 KNO 3) and maximization of flavonoids production (45 g L −1 saccharose, 0.09 g L −1 KH 2 PO 4 , 2.85 g L −1 KNO 3). According to the current results, other elicitation strategies should be assessed to make this bioprocess more efficient for manufacturing secondary metabolites with antioxidant activity from suspension culture of Capsicum baccatum L. var. pendulum cells.