This study aimed to characterize and select silk blossom genotypes (Calotropis procera) with forage potential. Between April and July 2014, we cultivated 89 genotypes in plastic tubes arranged in a randomized block design with three replications; each experimental plot was composed of 8 plants. The following characteristics were evaluated: plant height (PH), stem diameter (SD), number of leaves (NL), total leaf area (TLA), leaf fresh mass (LFM), stem fresh mass (SFM), root fresh mass (RFM), leaf dry mass (LDM), stem dry mass (SDM), and root dry mass (RDM). Significant differences (p < 0.05) among genotypes were observed for all characteristics, except for NL at 45 and 60 days after sowing (DAS) and for RFM at 60 DAS. Broad-sense heritability estimates and genotype means had medium and high values for most characteristics. Genetic variability among C. procera genotypes was observed. High gain selection was found for the characteristics TLA, PH, SFM, LFM, SDM, and LDM as the genotypes 79, 65, 48, 12, 51, 35, 63, 25, 1, and 46 are suitable for future breeding works to improve forage production.

The replacement of natural vegetation by crop systems directly impacts the soil organic matter fractions. The objective of this study was to evaluate the total organic carbon (TOC) and nitrogen (TN) contents in different fractions of the soil organic matter (SOM) of an Oxisol of the Brazilian semiarid region under different irrigated crops and different soil management systems. Seven treatments were evaluated, which consisted of two soil management systems (no - till and conventional tillage) and three crops (maize, sunflower and sorghum), using as reference the soil under a native forest (NF). The summer crops preceded common bean crops in the autumn - winter. The total organic carbon content, total nitrogen, carbon content in humic substances and their constituents (fulvic acids, humic acids and humin) and labile, non - labile and water - soluble carbon contents were evaluated two years and three months after the experiment implementation to determine the carbon lability (L) lability index (LI), partitioning index (CPI) and management index (CMI). The greatest carbon, nitrogen and organic matter contents in the soil surface layer (0.00 - 0.05 m) were found in crops under no - till system (NTS), especially maize. The crops under NTS presented greater carbon content in humic substances than the conventional tillage system (CTS) ones in the layer 0.05 - 0.10 m. The crops under NTS presented greater sustainability in the Brazilian semiarid region compared with those under CTS, as shown by their higher CMI in the soil surface layer.

The aim of the present study was to identify fungal pathogens associated with prickly pear rot and the main components of squamous rot on plantations in the semiarid region of the state of Paraíba, Brazil. Pathogens were identified morphologically. The determination of the main components of squamous rot intensity was based on the incidence and severity of the disease. Fifteen genera of fungi were associated with rot, including Scytalidium sp., which was found on all plantations. The analyses indicated that relative humidity and rainfall favored the intensity of rot more than temperature. At least three pathogens were found to be associated with a high incidence of rot in prickly pear species in the semiarid region of the state of Paraíba, Brazil, but Scytalidium sp. was the most widely distributed. Moreover, the disease caused by this fungus intensifies and progresses under conditions of high humidity at moderate temperatures.

Prickly palm cactus husk was used as a solid - state fermentation support substrate for the production of cellulolytic enzymes using Aspergillus niger and Rhizopus sp. A Box - Behnken design was used to evaluate the effects of water activity, fermentation time and temperature on endoglucanase and total cellulase production. Response Surface Methodology showed that optimum conditions for endoglucanase production were achieved at after 70.35 h of fermentation at 29.56°C and a water activity of 0.875 for Aspergillus niger and after 68.12 h at 30.41°C for Rhizopus sp. Optimum conditions for total cellulase production were achieved after 74.27 h of fermentation at 31.22°C for Aspergillus niger and after 72.48 h and 27.86°C for Rhizopus sp . Water activity had a significant effect on Aspergillus niger endoglucanase production only. In industrial applications, enzymatic characterization is important for optimizing variables such as temperature and pH. In this study we showed that endoglucanase and total cellulase had a high level of thermostability and pH stability in all the enzymatic extracts. Enzymatic deactivation kinetic experiments indicated that the enzymes remained active after the freezing of the crude extract. Based on the results, bioconversion of cactus is an excellent alternative for the production of thermostable enzymes.

The knowledge about genetic diversity of jatropha crop is important for genetic conservation resources and breeding of this species. The aim of this study was to evaluate the genetic diversity and performance of jatropha clones through morphological characterization to selection of clonal varieties for biofuels production. The clones were obtained through shoot cuttings from previous selection in a population of half - sibs progenies. The morphoagronomic analyses of clones was carried out at 180 days after transplantation and were evaluated plant height, stem diameter, number of primary branches and number of secondary branches, number of bunches and number of fruits per plant. Evaluating clones performance, significant results were found for the number of secondary branches. About analysis of genetic diversity, the measures of dissimilarity genetic varied from 0.62 to 13.11, this way, the UFRBPR14 and UFRBPR15 clones were more divergent. The Tocher method was efficient to verify formation of four groups. The characteristics that most contributed to the divergence among clones were branches number, height and number of bunches, and, stem diameter had lower contribution. The jatropha clones differed only in the secondary branches number and multivariate analysis showed divergence among the jatropha clones with formation of four groups. Also, branches number, plant height and number of bunches were characteristic that contributed to genetic divergence.

The aim of this study was to evaluate the performance of progenies from Citrullus lanatus var. lanatus (cultivated watermelons) when crossed with progenies from C. lanatus var. citroides (fodder watermelon with a historic of resistance to the nematode Meloidogyne enterolobii). The parents and their F1s were evaluated for resistance to this nematode. In the initial stages of eleven treatments, watermelon seedlings plantlets were transplanted to plastic bags of six kilograms once the first leaves developed. Ten inoculated plants with 5,200 eggs in the soil near the stem of the plant and four non-inoculated ones were used in each treatment, in a complete block design. Sixty-two days after sowing, the following characteristics were evaluated: the length of the aerial part of the plant (LAP, in m), fresh mass of the aerial part (FMAP, in g), root fresh mass (RFM, in g), egg number (EN) and reproduction factor (RF). A comparison between the averages of inoculated and non-inoculated plants was performed using Scott-Knott test at 5% and the diallelic analysis was performed using the GENES program. The morphological characteristics did not allow for the identification of the parent plants or the F1s with respect to nematode resistance, but the variables EN and RF were useful for such identification. The analyses of the general and specific combining abilities indicate highly significant effects with respect to this resistance, showing additive gene effects as well as dominance and epistatic gene effects, allowing for identification of parents and F1s that can be used in watermelon breeding programs to improve resistance to the M. enterolobii.

The present study aimed at evaluating the effect of different treatments to overcome dormancy of Luffa operculata seeds. The tests were conducted at the Laboratory of Seed Analyzes of the Federal Univer-sity of Paraíba, in the city of Areia-PB. The seeds of L. operculata were submitted to scarification treatments with sandpaper, cutting with scissors, imbibition in cold water, immersion in hot water and immersion in sulfu-ric acid. In evaluating the effect of treatment, was determined percentage, first count and germination index speed as well as length and dry mass of roots and hypocotyl. The mechanical scarification with sandpaper and cutting with scissors with or without imbibition in cold water for 12 hours are recommended for overcoming dormancy of L. operculata seeds.

Los objetivos del trabajo fueron evaluar la calidad sanitaria en cariopsis de maíz (Zea mays L.) infectados por F. graminearum provenientes de plantas inoculadas en diferentes momentos de la floración y determinar la ubicación de F. graminearum en los tejidos de cariopsis de maíz. Se evaluó la patología de los cariopsis y se determinó la calidad sanitaria de las espigas inoculadas con F. graminearum en diferentes mo-mentos de floración en el Campo Experimental de la Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla – Santa Fe, Argentina. Para determinar la ubicación de F. graminearum en tejidos del cariop-sis de maíz se realizaron cortes histológicos en los cariopsis con probables síntomas de enfermedad mediante técnicas de corte por congelación, diafanización, tinción y técnica de inclusión en parafina y coloración y se utilizó la Técnica de Rayos X para observar el efecto de la colonización por F. graminearum en los tejidos se-minales. Se observaron diferencias entre híbridos, sin embargo F. graminearum afectó de manera similar los cariopsis en los tercios superior, medio e inferior de la espiga de maíz; la incidencia por F. graminearum es baja en cariopsis de maíz debido a la mayor agresividad de F. verticillioides al ingresar al estigma del maíz con el grano de polen. F. graminearum y F. verticillioides no penetran al interior del cariopsis, sino que llegan has-ta las capas internas del pericarpo y no afectan la capa de aleurona y el embrión del cariopsis de maíz.

Calotropis procera (Aiton) W.T. Aiton - Apocynaceae (silk-flower) is an important species for several usages: ornamental, forage, timber, textile and medicine, that justify its study. We investigated the physiological behavior and the vigor of seeds under different storage conditions. There were performed month-ly evaluations of germination, seedling emergence, speed of emergence, seedling length and weight of seedling dry matter, during 180 days. Experimental design was completely randomized with a 6x5x3x2 factorial, using combinations of six storage periods (30, 60, 90, 120, 150 e 180 days), five moisture contents (30, 24, 18, 12 e 7%), three package types (paper bags, plastic bags and PET bottles) and two environmental conditions (chamber: 16 °C a 18 °C and laboratory: 27 °C a 30 °C, both environments with 50±5%) with four replications of 50 seeds. Data were analyzed using analysis of variance using F (p≤ 0.05) test to treatments and Tukey test for averages comparison, with polynomial regression analysis considering the storage periods. There were con-cluded that silk flower seeds presented orthodox physiological behavior; the vigor decreased when stored for 180 days; silk flower seeds with 7% moisture content are preserved efficiently in paper bags and controlled environment for 90 days.

This study aimed at evaluating the performance of Nelore cattle during growth classified for different classes of frame size regarding body weights and morphometric measures at different ages. Weights and morphometric measures Nelore bulls up to 1 year of age were monthly recorded. The characteristics evalu-ated were birth weight, 120, 205, 240 and 365 days of age, withers height and rump height, thoracic perimeter, distance between pin bones, distance between hip bones and chest width, depth of chest, space under sternal and hip length. Frame size scores classified as medium, large and extreme, were estimated using equations and tables according to Beef Improvement Federation (BIF). Data were subjected to analysis of variance and Tukey-Kramer test at 5% probability and analyses were performed by canonical variables and the grouping analyses of genotype by method of Tocher. The animals with larger class of frame size were heavier and morphometric measurements as well, when compared with animals classified for smaller class. The correlation between weight at different ages were higher. The weight correlates with body features positively, indicating that the weight gain of the animals increased their influence on the frame size. Cluster analysis resulted in three distinct genetic groups that have similar within the group and genetic divergence between them.