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The results of 12 sugarcane cultivars evaluated against sugarcane orange rust disease on the plant strain in two planting cycles (spring and cold) are shown. The number of pustules and the length of the most frequent pustule on leaves +1, +3, +5 and +7 at three, four, five, six and seven months of age were evaluated in a 2 cm² sampling station. The percentage of area occupied by pustules was calculated using a mathematical expression. Data were processed through the SPSS statistical package and analysis of variance and Tukey's test were performed for the sources of variation: leaves, evaluation dates, cultivars and cycles. The results showed differences for all sources of variation, leading to the conclusion that, although the affectations are not of great intensity, there are differences in the manifestation of symptoms in the different cultivars, and that studies to determine the presence of the disease and resistance of the genotypes should be carried out with cold plantings, also evaluating the +3 or +5 leaf when the crop is three and five months old. [ABSTRACT FROM AUTHOR]

In Cuba, sugarcane brown rust (Puccinia melanocephala) is one of the most important diseases and orange rust (Puccinia kuehnii) is considered a potentially dangerous disease. The objectives of the present investigation were: to quantify the development of brown and orange rust; to determine the influence of the planting time and age of the plants on the severity of these diseases; and the period in which the levels of both rusts are the highest. It was found that the months of planting have a very similar influence on the manifestation of the symptoms of both rusts with greater affectation in the plantations that were carried out from July to December and in the month of April. The severity of brown rust was significantly higher from three to five months of age after planting, however, in orange rust the severity remained above the average observed until seven months. The severity of orange rust increased with the age of the plants in the plantations that were carried out from January to April. Unlike brown rust, regardless of the age of the plants, the severity of orange rust can be increased when favorable environmental conditions exist. [ABSTRACT FROM AUTHOR]

In Cuba, the methodology used for the evaluation of resistance to sugarcane brown rust (Puccinia melanocephala Sydow and P. Sydow) lacks quantitative aspects, as well as the definition of representative localities for resistance tests and has limited patterning. In order to establish new evaluation criteria that contribute to the improvement of the Evaluative System of the Resistance to the brown rust in the Program of Improvement of the Sugar Cane in Cuba, during the 2007 - 2015, six patterns of known reaction and 11 commercial cultivars were study in 6 localities. The variables length, quantity and percentage of leaf area occupied by pustules and length of the major pustule were recorded. The six localities of resistance test were ratified and the evaluations must be carried out in the middle third of the leave +3 of ten plants at three and five months of age, with an evaluation scale with new quantitative criteria (area occupied by pustules and length of the major pustule). Cultivars SP70-1284, C88-380 and C323-68 are included as standards. C334-64, Ja60-5 and B4362 are reclassified. The methodology for evaluating the brown rust of sugarcane in Cuba is modified and a new scale of evaluation of the disease is proposed. [ABSTRACT FROM AUTHOR]

In Cuba, the methodology used for sugarcane brown rust resistance evaluation has limited patterning, which makes it difficult to adequately handle cultivars in the intermediate categories of reaction, provided that from an agro-productive point of view they are interest. Six known reaction patterns and 11 commercial cultivars were studied. The variables, length, amount and percentage of leaf area occupied by pustules were recorded, as well as the length of the major pustule. The application and interpretation of statistical methods allowed to ratify as highly resistant to PR980, resistant to Ja64-11 and as susceptible My5514. The cultivars SP70- 1284 (moderately resistant), C88-380 (moderately susceptible) and C323-68 (susceptible) are included as new standards. They are reclassified to C334-64 (moderately susceptible), Ja60-5 and B4362 (highly susceptible). [ABSTRACT FROM AUTHOR]

To develop a system that increase the precision in the resistance evaluations to sugarcane brown rust disease through the use of the quantitative sampling, six cultivars of differential behavior versus the disease (PR980, My5514, Ja60-5, C334-64, C323-68 and B4362) were studied. A random block experimental design with three replications was used in a heavy infections conditions obtained from the cultivar highly susceptible B4362. The evaluations were done at three and five months of age, in the three-thirds: bottom, half and top of the +1, +3 and +5 sugarcane plant leaves of 10 plants for replica. The variable total leaf area affected of the leaf and in each third was analyzed. In 2 cm2 were observed the long and wide of the biggest and more frequent pustule, the total of pustule and the area of the biggest and more frequent pustule, and the area percentage occupied by the most frequent pustule by each cm2 were determined. Variance analysis and Tukey tests as well as confidence intervals analysis to determine the coefficient to use as constant of the pustule width, due to the little variation of this parameter were realized. The +3 leaf represented the half infection of the incidence of the brown rust, constituting for it the most appropriate to carry out the observations and the half third. An equation was also obtained to calculate the area occupied by pustules with a high level of confidence. [ABSTRACT FROM AUTHOR]

The sugarcane brown rust disease is caused by fungus Puccinia melanocephala Sydow & P. Sydow and it is one of the more importance diseases. The environment where the sugarcane is cultivated is constituted by numerous factors and its combination contributes to the formation of different development and production conditions, what influences in the varietal disease resistance. With the objective of to characterize and to define the resistance tests location to the brown rust disease were carried out experiments in 6 location of the country. Eleven varieties and six patterns were studied. The climatic variables were analyzed during the period in each location and they were carried out evaluations in different ages of the plant and number of the leaves. The quantity of pustules, long of the most frequent pustules, size of the biggest pustules and area percentage occupied by pustules were evaluated. The data were analyzed statistically. Differential behavior of the locations and the importance of the relative humidity and the temperatures in the manifestation of the disease symptoms were proven. All the locations were important although similarity exists between Matanzas and Villa Clara and between Camagüey and Holguín. Mayabeque and Santiago de Cuba didn't present similarity with any other one. These 6 locations can be used for the resistance tests and to define the progenitors' Santiago de Cuba, Holguín, Villa Clara and Mayabeque. [ABSTRACT FROM AUTHOR]

Sugarcane orange rust (Puccinia kuehnii (W. Krüger) E.J. Butler) is considered an emerging disease in the Western Hemisphere and with high potential for damage. It was detected in Cuba in late 2008, which is why phytosanitary surveillance was established on its dispersion and incidence in the sugarcane plantations of the country. The objective of this work was to update the status of this disease in Cuba from the processing of data from research and surveys conducted in the period 2009-2017. Evaluations were carried out in the risk areas through systematic sampling in germplasm banks, varieties gardens, experimental areas and seed banks, including those established from "in vitro" plants. In addition, surveys were carried out in areas of commercial plantations, validation areas of new cultivars and areas of certified seed production, where 10 stems were randomly evaluated in three sampling stations following the diagonal of the field. P. kuehnii is found in the 13 provinces producing sugarcane in Cuba. Most infected genotypes were found in areas of experimental stations, mainly in the provinces of Mayabeque, Villa Clara and Camagüey. The distribution of this pathogen in the national territory is classified as low prevalence; however, the number of infected commercial cultivars rises to 30. [ABSTRACT FROM AUTHOR]

The goal of this paper was to assess the behavior of chemical composition indicators (dry matter, ash, gross protein, phosphorous, and potassium) of two new sugar cane varieties, based on plant fractions and re-shoot age. Chemical analyses were made to several plant fractions (whole, nodes, stem) at different re-shoot ages (six, eight, and eleven months). Forage variety My5514 was used as control. Multifactorial variance analyses were also made. The results demonstrated that the chemical composition indicators of ash, gross protein, phosphorous, and potassium in sugar cane, depended on the age of re-shoot, variety, and plant fraction. Dry matter also depended on the re-shoot age and plant fraction. [ABSTRACT FROM AUTHOR]

In vitro digestibility of two new sugar cane cultivars for forage was determined. Three runs were performed using gas from cattle gases as inoculum. The integral fraction of the plant at 6; 8 and 11 months of reshoot were studied. Forage cultivar My5514 was used as witness, and to determine the parameters, the Ørskov and McDonald (1979) model modified by Correa (2004) was used. Simple variance analyses were made and the differences were determined by the Tukey test for P < 0.05. The results showed that the two new cultivars produced similar in vitro gas volumes to My5514 forage cultivar, and were even higher at 8 and 11 months of age. Eight months later, the new cultivars produced the highest in vitro gas values. The values achieved for the production parameters of in vitro gas, speed (0.011 h-1-0.033 h-1) and potential for gas production (32.7 ml-52.1 ml) were high; on its turn, lag had low values (2.10 h-4.57 h). [ABSTRACT FROM AUTHOR]