The meiotic and mitotic behavior of regenerated plants derived from a long-term callus culture, designated 12-F, was analyzed. This culture was heterozygous for an amplification of the heterochromatic knob on the long arm of chromosome 7 (K7L). We aimed to investigate if the amplification resulted from a breakage-fusion-bridge (BFB) cycle or from unequal sister chromatid recombination. Therefore, C-banded mitotic metaphases and pachytene, diakinesis, and anaphase I of regenerated plants were analyzed. Additionally, the occurrence of alterations in K7L was investigated in C-banded metaphases from short-term callus cultures derived from lines related to the donor genotype of the 12-F culture. As a result, plants homozygous and heterozygous for the amplification were detected. Meiosis was normal with few abnormalities, such as a low frequency of univalents at diakinesis. In the callus cultures a chromosome 7 with knobs of different sizes in the sister chromatids was detected and interpreted as a result of unequal crossing over. Other chromosomal alterations were consistent with the occurrence of BFB cycles. The finding of unequal crossing over in the cultures supports the conclusion that the amplification in the culture 12-F would be derived from this mechanism. If the amplification was derived from a BFB cycle, the terminal euchromatic segment between knob and the telomere would be deleted, and possibly, homozygous plants would not be viable.

ABSTRACT. Maize landraces derived from tropical germplasm represent an important source of genetic variability, which is currently poorly understood and under-exploited by Brazilian crop breeding programs. The aims of our study were to a) estimate the genetic diversity across 48 varieties of maize landraces cultivated at different locations in the States of Rio Grande do Sul (RS) and Paraná (PR) by means of random amplified polymorphic DNA (RAPD), simple sequence repeat (SSR), and amplified fragment length polymorphism (AFLP) markers; b) cluster these varieties based on their genetic similarity estimates, and c) establish possible correlations between genetic similarity and germplasm collection sites. Maize landrace accessions were genotyped through the 30 RAPD, 47 SSR, and 25 combinations of AFLP primers. The results revealed high levels of variability across landraces within and between collection sites. AFLP analysis resulted in amplification of 762 polymorphic fragments and a polymorphic index of 40.3%, followed by RAPD with 335 fragments (81.9%) and SSR with 105 fragments (78.3%). The genetic similarity estimates of the investigated landraces ranged from 41 (SSR) to 74% (AFLP), and the amplitudes of these indices were notably similar between RAPD and SSR, as well as between AFLP and joint analysis. Regarding the RAPD and AFLP dendrograms, groups comprising accessions from RS prevailed, whereas SSR comprised varieties from both collection sites. Groups exclusive to RS or PR support the hypothesis that divergence between groups is possible owing to the fixation of regional adaptation alleles and to spatial barriers hindering genetic flow between locations.

O tomate seco apresenta um consumo crescente, principalmente como ingrediente de pizzas e lasanhas, e na forma de aperitivo. A pesquisa avaliou o processo de produção de tomate seco de quatro cultivares comerciais (Italiano, Débora Plus, Santa Cruz, Delícia) e a qualidade dos produtos prontos. O tomate foi fatiado em quatro cortes longitudinais, sentido pedúnculo-ápice, e as fatias tiveram suas massas loculares removidas. O secador foi regulado nas primeiras três horas para 100ºC, seguido de 80ºC até completar a secagem do produto, o qual apresentou uma umidade residual em torno de 60%. A cv. Delícia produziu a maior perda de 39,8% durante o preparo das fatias frescas, sendo que as perdas para as demais cultivares variaram entre 32,7 a 34,3%. Os rendimentos dos tomates inteiros em produtos prontos foram iguais a: cv. Débora Plus 9,1%; cv. Santa Cruz 8,9%; cv. Delícia 8,6%; e cv. Italiano 8,3%. O maior tempo de secagem de 9 horas e 25 minutos foi para a cv. Delícia; as demais apresentaram um mínimo de 8 horas e 10 minutos (Italiano) e um máximo de 8 horas e 35 minutos (Santa Cruz). Os tomates secos das cultivares Italiano e Débora Plus apresentaram-se levemente adocicados; o da cv. Santa Cruz foi ainda menos; e, esta característica foi de difícil percepção para o da cv. Delícia, que também teve uma mastigação não suave e mais prolongada. Apesar da diferença, os produtos tomates secos obtidos a partir dessas cultivares não diferiram significativamente quanto ao paladar quando degustados por provadores não treinados.

RESUMOO minimilho, uma espiga imatura ainda não fertilizada, vem ganhando importância no Brasil para o consumo como conserva, principalmente por ser agradável e apresentar baixo valor calórico. a pesquisa se propôs avaliar a qualidade das conservas de quatro híbridos; determinar a composição nutricional destes híbridos; e determinar o rendimento de minimilho para a produção de conserva. Os procedimentos de acidificação aplicados durante o processamento, essencial para a qualidade dessas conservas, resultaram em produtos seguros para o consumo. Os provadores preferiram a conserva de minimilho mais ácida, apresentando um valor de pH projetado para o equilíbrio de 3,9 ao invés de 4,2, bem como, a conserva contendo a salmoura de 4,0 %, p/v, de sal. as conservas dos híbridos DKB 214, p 3021, aG 6018 e DKB 215 não diferiram estatisticamente quanto ao paladar. as composições nutricionais desses híbridos foram similares e confirmaram se tratar de um produto de pouco valor calórico, apresentando concentrações porcentuais baixas de carboidratos digeríveis mais proteínas (6,87-7,21 %) e insignificante de lipídeo (< 0,30 %). Considerando o rendimento em massa média de minimilho sem palha em relação à matéria-prima com palha, o híbrido p 3021 foi o recomendado, pois, apresentou 25,90 % a mais em relação ao híbrido de menor rendimento aG 6018.PalavRaS-chavE: Zea mays, conservas de minimilho, agroindústria, alimento funcional, composição nutricional. Processing of canned baby corn: assessment of cultivars aBSTRacTBaby corn, immature corn-cob yet fertilized, has become important for the canning in Brazil, because it is specially pleasant and low-calories. This research proposed to evaluate the quality of canned baby corn from four cultivars; determine the nutritional compositions of these cultivars; and determine the baby corn yield for canning. The acidification procedures used in processing resulted in a product safe for consumption. The tasters preferred the canned baby corn with highest acidity, which had an estimated pH 3.9 for stabilization, instead of 4.2 and canned with 4.0% brine. The canned of the cv. DKB 214, p 3021, aG 6018 and DKB 215 were considered equally palatable by the tasters. The nutritional compositions of the four cultivars were similar and these were low-calories because they had law-concentration in both the carbohydrate and the protein, and the lipid was insignificant (lower than 0.30%). Thus, considering the yield in baby corn for the canned, the cv. p 3021 was recommended, because it had a yield of 25.90% higher than the cv aG 6018, which had the lower.KEy-wORdS: Zea mays, baby corn canned, agroindustry, functional food, nutritional composition.

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AbstrAct:The present study aimed to estimate the genetic divergence among corn half-sib progenies seeking to direct recombination between contrasting and superior progenies for green corn production. Ninety-six progenies were evaluated in a randomized block design with 3 replications, and 18 characteristics associated with agronomic adaptation and green corn yield were measured. The genetic divergence was estimated using The grouping allowed to identify superior and contrasting progenies for green corn production. The recombination of these progenies allows increasing genetic variability and the frequency of alleles favorable to the green corn production.

ABSTRACT. The aim of this study was to determine the Al concentration and the period of exposure of the roots of maize hybrids in minimal solution for efficient selection of genotypes that are Altolerant. Two experiments were performed (48 and 96 h of exposure) with increasing doses of Al in minimal solution; the block design was completely randomized in a split-plot design with 3 replications. By assessing differences in root growth (cm) and the percentage of inhibition of the growth of the main root (%), a marked decrease was observed in maize root growth with increasing Al concentration in the solution. Exposure of the roots to 2 mg/L Al for 48 h in minimal solution was the most efficient for selecting sources of tolerance, particularly for the hybrids H 44 and H 38.