RESUMO Algodão de seda é uma espécie vegetal adaptada a vários ecossistemas e tem se destacado pela importância econômica e ecológica. Nós avaliamos o perfil de amplificação de 23 iniciadores ISSR e selecionamos loci polimórficos para estudos genéticos de uma população natural de Calotropis procera por meio da coleta e extração de DNA genômico de 33 indivíduos. O DNA genômico foi extraído usando o protocolo sorbitol e CTAB 2% e os produtos de amplificação ISSR foram resolvidos por eletroforese. Com base no perfil de amplificação, os 23 iniciadores foram classificados como adequados, razoáveis e inadequados. Descrevemos a qualidade dos iniciadores considerando o número total de bandas, média das bandas por iniciador, porcentagem de polimorfismo, diversidade genética de Nei (heterozigosidade esperada - He), assumindo o equilíbrio de Hardy-Weinberg e conteúdo das informações polimórficas (PIC). Todos os iniciadores ISSR apresentaram perfil de amplificação, os quais geraram 173 marcas com média de 7,5 loci por iniciador. Porém, dos 23 iniciadores testados, apenas 18 permitiram amplificação visível e de alta qualidade, que foram classificados como adequado e polimórfico. Também observamos média de 0,30 e 0,24 para as estimativas de PIC e He, respectivamente. Os iniciadores DiCA3`RG, TriAGA3`RC e TriCGC3`RC foram altamente transferíveis para C. procera (apresentaram qualidade para amplificação com boa reprodutibilidade), com valores de PIC superiores a 0,40, He superior a 0,30 e polimorfismo superior a 86%.

ABSTRACT Sodom apple is a plant species adapted to various ecosystems and has stood out for its economic and ecological importance. We evaluated the amplification profile of 23 ISSR primers and selected polymorphic loci for genetic studies of a natural population of Calotropis procera by collecting and extracting genomic DNA from 33 individuals. Genomic DNA was extracted using the sorbitol protocol and 2% CTAB and the ISSR amplification products were resolved by electrophoresis. Based on the amplification profile, the 23 primers were classified as suitable, moderate, and unsuitable. We described the quality of primers considering the total number of bands, mean bands per primer, percentage of polymorphism, Nei’s genetic diversity (expected heterozygosity – He), assuming Hardy-Weinberg equilibrium and the polymorphic information content (PIC). All ISSR primers showed an amplification profile, which generated 173 bands with an average of 7.5 loci per primer. However, only 18 out of the 23 tested primers allowed visible and high-quality amplification, which were classified as suitable and polymorphic. We also observed a mean of 0.30 and 0.24 for PIC and He estimates, respectively. The DiCA3`RG, TriAGA3`RC, and TriCGC3`RC primers were highly transferable to C. procera (they presented quality for amplification with good reproducibility), with PIC values higher than 0.40, He higher than 0.30, and polymorphism higher than 86%.

ASTRACT. This study evaluated the effect of increasing levels of leucaena forage in sorghum: forage. In addition to pure sorghum, it was evaluated different levels of inclusion of leucaena (15, 30 and 50%) at the time of ensiling. Forage was ensiled in PVC tubes (100 mm diameter, 500 mm length) under the density of 500 - 600 kg m-3, a total of 20 silos were prepared, which were opened 35 days after ensiling. There was no effect (p > 0.05) of leucaena inclusion levels for pH, water activity (Aw) and total ammonia nitrogen (total NH3-N). There was an increasing linear effect (p < 0.05) for the content of dry matter (DM), crude protein (CP) and lignin that increased from 33.47 to 34.75%, 7.82 to 16.05% and from 7.29 to 9.93%, at the levels from 0 to 50% inclusion of leucaena, respectively. There was a decreasing linear effect (p < 0.05) for neutral detergent fiber corrected for ash and protein (NDFcp) and hemicellulose, which reduced from 56.65 to 48.37% and from 24.07 to 17.67% at the levels of 0 and 50% inclusion, respectively. For the ash content, there was a quadratic effect (p < 0.05), with a maximum at 8.3% with 8.9% inclusion of leucaena. The inclusion of up to 50% leucaena into sorghum silage is recommended, because, in addition to maintaining the fermentation quality, it also improved nutritional quality of sorghum silage.