Napier grass [Cenchrus purpureus (Schumach.) Morrone], also known as elephant grass, is an important tropical forage that has the potential to become an alternative feedstock for energy production. Knowledge about the mode of reproduction and outcrossing rate is essential to select the best strategy to apply in breeding programs to develop new cultivars for application in energy and forage production systems. The objective of this work was to evaluate the outcrossing rate in two Napier grass breeding populations. Six microsatellite markers were used to genotype 28 half‐sibling families totaling 588 individuals, and pollen viability was checked by fluorescein diacetate test (FDA) methodology. A total of 14,603 pollen grains were assessed; 7751 (53%) were considered viable, and 6852 (47%) were considered sterile. Forty‐two alleles were found among all evaluated individuals, and analysis of molecular variance results showed that 14% of variance occurred among half‐siblings and 86% occurred within half‐siblings. Comparison of molecular data among parental and half‐sibling populations found 95.3% of seeds derived from outcrossing, indicating that Napier grass is predominantly allogamous. Currently, directional crosses and hybrid formation in Napier grass depend on the inflorescence protection and pollen collection of selected individuals. Since our results suggest that the self‐fecundation rate is very low (5%), other strategies like unprotected directional crosses can be applied to implementation of large‐scale hybrid production.

Agapanthus (Agapanthaceae) has 10 species described. However, most taxonomists differ respect to this number because the great phenotypic plasticity of the species. The cytogenetic has been an important tool to aid the plant taxon identification, and to date, all taxa of Agapanthus L'Héritier studied cytologically, presented 2n = 30. Although the species possess large chromosomes, the group is karyologically little explored. This work aimed to increase the cytogenetic knowledge of Agapanthus africanus (L.) Hoffmanns by utilization of chromosome banding techniques with DAPI / CMA 3 and Fluorescent in situ Hybridization (FISH). In addition, flow cytometry was used for determination of DNA content and the percentage of AT / GC nitrogenous bases. Plants studied showed 2n = 30 chromosomes, ranging from 4.34 -8.55 µm, with the karyotype formulae (KF) = 10m + 5sm. Through FISH, one 45S rDNA signal was observed proximally to centromere of the chromosome 7, while for 5S rDNA sites we observed one signal proximally to centromere of chromosome 9. The 2C DNA content estimated for the species was 2C = 24.4 with 59% of AT and 41% of GC. Our data allowed important upgrade for biology and cytotaxonomy of Agapanthus africanus (L.) Hoffmanns.

Napier grass is a perennial tropical forage that is used in beef and dairy production systems. Despite its significance in animal nutrition, molecular information available, such as microsatellite or simple sequence repeat (SSR) or single nucleotide polymorphism (SNP) markers, is limited. Using an assembled transcriptome, 50 novel SSR markers were developed, of which 21 were found to be polymorphic. These polymorphic markers were tested for DNA fingerprinting of Embrapa cultivars, five of which revealed distinct allele patterns for cultivar identification. SSR markers 05, 17, and 44 identified a unique pattern in the BRS Kurumi cultivar. The BRS Capiaçu cultivar was identified using SSR markers 17, 43, and 44. The Pioneiro cultivar exhibited a rare fragment amplification pattern using SSR marker 46, while SSR marker 44 revealed a distinct allele in the BRS Canará cultivar. SSR marker panels could be utilized as DNA fingerprinting tools to assist in cultivar identification.

A lignina é uma molécula que confere sustentação e resistência às plantas vasculares. Em plantas forrageiras, como Urochloa humidicola e Cenchrus purpureus, a molécula interfere negativamente na digestibilidade da fibra vegetal no rúmen de bovinos. Na produção de biocombustíveis, a lignina presente na biomassa dificulta a hidrólise enzimática; na combustão da biomassa, contribui para o aumento do poder calorífico. Dada sua importância, faz-se necessário entender o funcionamento da via metabólica associada a lignina para seleção de genótipos superiores. O objetivo deste trabalho foi identificar genes relacionados à produção de lignina em U. humidicola e C. purpureus, além do desenvolvimento de marcadores moleculares microssatélites. Neste estudo foram selecionados, para cada espécie, quatro genótipos com maior produção de lignina, e quatro genótipos de menor produção. A análise dos genes diferencialmente expressos em U. humidicola revelou 196 genes a nível de significância de p <0,05 . Em destaque, genes do citocromo P450, da enzima 4CL e da biossíntese de flavonoides. 53 genes foram diferencialmente expressos em C. purpureus, destacando-se os genes glicosiltransferase e os relacionados a biossíntese de terpenos/terpenoides. A partir de um novo agrupamento realizado, foi possível identificar os genes MYB e peroxidase, além de genes de construção da parede celular. Com a construção do heatmap, detectou-se maior expressão da família gênica COMT, seguida das famílias CCoAOMT e PTAL. A partir do transcriptoma, foi possível descobrir novos marcadores microssatélites nas duas espécies, que foram testados para amplificação em U. humidicola e C. purpureus, além de identificação de padrão de bandas únicas em cultivares desta última espécie. Um total de 42 primers amplificaram em quatro amostras testadas de U. humidicola; 47 amplificaram em quatro amostras testadas de C. purpureus, sendo seis informativos na diferenciação de 21 cultivares testadas. Os genes identificados nos transcriptomas serão importantes na identificação dos genes mais promissores para futura manipulação genética. Os marcadores microssatélites desenvolvidos serão utilizados na identificação de cultivares e em estudos de diversidade dentro das populações de melhoramento.