ABSTRACT. Considering the expected genetic variability of elephant grass (Pennisetum purpureum), due to its cultivation in different continents, we characterized and estimated the genetic divergences between 46 accessions of elephant grass with different edaphoclimatic adaptations, using RAPD and ISSR markers. We evaluated, comparatively, the consistency of the information achieved with these markers. Twenty-six RAPD and 25 ISSR primers were employed. The RAPD markers produced 185 bands, 72% of which were polymorphic, with a mean of 5.11 polymorphic bands per primer. The 25 ISSR starters produced 216 bands; 76% were polymorphic, with a mean of 6.56 polymorphic bands per primer. The correlation between the genetic distances achieved by the RAPD and ISSR markers was 0.76, which is highly significant by the Mantel test. Based on UPGMA grouping, considering the point of sudden change, five and six groups were formed for the data from the RAPD and ISSR markers, respectively. Genetic diversity in elephant grass These markers provided partially concordant groups, indicating that these techniques can provide consistent information and consequently could be used in studies of genetic diversity among accessions.

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Elephant grass is a plant of tropical origin with high biomass-production potential that stands out today as an alternative energy source. The potential of its genotypes depends on the genotype × environment interaction. The objective of this study was to estimate the genotype × environment interaction and compare stability methods in elephant grass for biomass production in a biannual cutting regime. The experiment was conducted in a randomized block design with two replicates and evaluations of 73 elephant-grass genotypes in six cuts. The trait dry matter yield was utilized for the analysis of the genotype × environment interaction and the stability. The stability analysis methods employed were those of Yates and Cochran, Plaisted and Peterson, Wricke, Annicchiarico, Lin and Binns, and Huehn. Kang and Phan's ranking was adopted for all the methods. Spearman's coefficient was utilized to evaluate the degree of agreement between the different methods employed. Significant differences were observed for the genotype × environment interaction. Non-parametric Lin and Binns' and Annicchiarico's methods were more discriminating than the analysis of variance methods in the evaluation of stability and productivity of the tested genotypes.

ABSTRACT. Selection indices commonly utilize economic weights, which become arbitrary genetic gains. In popcorn, this is even more evident due to the negative correlation between the main characteristics of economic importance -grain yield and popping expansion. As an option in the use of classical biometrics as a selection index, the optimal procedure restricted maximum likelihood/best linear unbiased predictor (REML/BLUP) allows the simultaneous estimation of genetic parameters and the prediction of genotypic values. Based on the mixed model methodology, the objective of this study was to investigate the comparative efficiency of eight selection indices estimated by REML/ BLUP for the effective selection of superior popcorn families in the eighth intrapopulation recurrent selection cycle. We also investigated the efficiency of the inclusion of the variable "expanded popcorn volume per hectare" in the most advantageous selection of superior progenies. In total, 200 full-sib families were evaluated in two different areas in the North and Northwest regions of the State of Rio de Janeiro, Brazil. The REML/BLUP procedure resulted in higher estimated gains than those obtained with classical biometric selection index methodologies and should be incorporated into the selection of progenies. The following indices resulted in higher gains in the characteristics of greatest economic importance: the classical selection index/values attributed by trial, via REML/BLUP, and the greatest genotypic values/expanded popcorn volume per hectare, via REML. The expanded popcorn volume per hectare characteristic enabled satisfactory gains in grain yield and popping expansion; this characteristic should be considered super-trait in popcorn breeding programs.

The objectives of this study were to estimate the stability of dry biomass production of elephant grass genotypes under an annual harvest regime, in soil-climatic conditions of the Northern region of the Rio de Janeiro State, Brazil, and to compare methodologies for stability analyses of Yates and Cochran (YC), Plaisted and Peterson (PP), Annicchiarico (ANN), Lin and Binns (LB), Huenh (HU), and Kang and Phan (KP). A randomized block design with 83 treatments and two replicates was adopted. Four annual harvests were performed (2012-2015) and dry matter yield (DMY, t.ha.year) was evaluated. Individual and combined analyses of variance for DMY revealed significant effects for genotypes, harvests, and for the genotype x harvest interaction at the probability levels of 1 and 5%. Genotypes indicated by the YC and PP methods are associated with higher stability and lower DMY. The weighting of KP with YC and PP was highly effective in associating stability with DMY. The LB and ANN methods showed strong agreement with each other and produced similar classifications as to phenotypic stability, and so we recommend using one or the other. Genotypes Elefante Cachoeiro do Itapemirim, Cuba-116, Taiwan A-46, P241 Piracicaba, Taiwan A-144, Cameroon - Piracicaba, 10 AD IRI, Guaçu/I,Z,2, Mineirão IPEACO, Taiwan A-121, IJ7125 cv EMPASC308, 903-77, Mole de Volta Grande, and Porto Rico 534-B showed high stability and DMY, standing out as promising genotypes for the soil-climatic conditions of the Northern region of the Rio de Janeiro State. The methodologies based on ANOVA and non-parametric analyses were complementary and increased reliability in the recommendation of genotypes.

The purpose of this research was to select the development of superior genotypes of snap beans adapted to edaphoclimatic conditions of the North and Northwest of Rio de Janeiro State, Brazil, applying the mixed model methodology. The test was installed and carried out in the experimental area of the Instituto Federal Fluminense (IFF), located in the municipality of Bom Jesus do Itabapoana, Rio de Janeiro State, Brazil, using the modified SSD (Single Seed Descent) method. The experiment was of randomized block design with three replications. We evaluated weight of pod per plant and number of pod per plant in ten progenies from the snap bean breeding program of the Universidade Estadual do Norte Fluminense (UENF); individual plants were assessed in each plot and in each replication (block). All progenies had mean productivity superior to 1 kg of pod per plant and 144 pods per plant. The 7 and 2 progenies, which came from the crossings between (UENF 7-5-1) L6 × L20 (UENF 14-3-3) and (UENF 7-5-1) L6 × L13 (UENF 7-20-1), stood out from the others, as they led to a higher predicted additive gain for the two evaluated traits. We concluded that the selection for production of snap beans and grains applying BLUP enabled the prediction and achievement of significant genetic gains for breeding snap beans for subsequent generations

The objective of this study was to evaluate the morpho-agronomic traits of eighty five accessions of elephant grass (Pennisetum purpureum Schum.) from the germplasm bank located at the Experimental Field of the State Center for Research on Bioenergy and Waste Recovery (Centro Estadual de Pesquisa em Agroenergia e Aproveitamento de Resíduos). The experimental design was a randomized block with two replicates, in an annual-harvest system. The evaluated traits were: percentage of dry matter (%DM), dry matter yield (DMY), number of tillers per linear meter (NT), plant height (HGT), stem diameter (SD), leaf blade width (LW) and leaf blade length (LL). Each cut and variable underwent variance analysis and the Scott-Knott test (P<0.05). Tocher's optimization method, Mahalanobis distance and canonic variables were used for the multi-traits, and importance of the characters in the canonic variables. The following elite genotypes were identified by the Scott-Knott test at 5%: Rico 534-B,