Adenium obesum (Forssk.) Roem. & Schult., popularly known as desert rose, has become a valuable ornamental plant. In floriculture, the production of hybrids is prioritized. Hence, knowledge on floral biology and sexual reproduction of the target species is fundamental. The objectives of this study were: (1) to test sucrose concentrations and temperatures for in vitro germination of A. obesum pollen grains; (2) to identify the effect of temperature on the viability of A. obesum pollen grains; and (3) to evaluate the viability of pollen grains and stigma receptivity in pre-anthesis, at flower opening, and 72 h post-flower opening in three accessions of A. obesum. A significant relationship between temperatures and sucrose concentrations was observed in the in vitro germination test. The highest percentage of in vitro germination of pollen grains, 39.81%, was observed at an estimated temperature of 26.05 °C. Desert rose accessions maintained in biochemical oxygen demand (BOD) chambers at 30 °C during a 16-h light photoperiod showed faster flowering, and temperatures ≥ 25 °C induced pollen grain viability percentages above 69%. Temperature is one of the most important abiotic factors, influencing mainly in pollen germination, pollen tube growing and in efficiency fertilization. The ICA-wd accession stood out and can be considered a pollen donor in artificial pollination. The stigmas of flowers were receptive from a day before flower opening until three days after. The two parameters presented above, stigma receptivity and pollen viability, allow inferences about the appropriate time for successful pollination and subsequent fertilization in desert roses.

Rose is a plant of high nutritional requirement, susceptible to powdery mildew disease caused by fungus Oidium leucoconium, which causes leaf fall and losses in flower production. The objective of this study was to evaluate powdery mildew severity in rose cultivar ‘Grand Gala’ in response to organic fertilization and the application of alternative products to disease control. The first experiment was set in a factorial arrangement, with 5 alternative products: spraying with water as a control (PA), lime sulfur (CS), neem oil (ON), mixture of sodium bicarbonate and canola oil (BC) and coffee pyroligneous acid (APC) and 2 organic fertilizers: chicken manure (EA) and biofertilizer based on banana stalk (B). Disease severity was assessed at 0, 15, 30 and 45 days after the treatments. In the second experiment, asymptomatic leaves or with different powdery mildew severity levels were sprayed only once with the same alternative products mentioned above. Severity was assessed at 0, 7 and 14 days. The organic fertilizations did not influence the reduction in powdery mildew severity in rose. At 45 days, APC yielded a greater reduction in disease severity (81.6%), followed by treatments based on BC, ON and CS. Greater reduction in disease severity in experiment 2 occurred in the treatments of BC and CS, followed by APC. Therefore, it is possible to conclude that APC and the BC have the potential to control rose powdery mildew in an organic cultivation system.

O cártamo (Carthamus tinctorius L.) é uma espécie que tem grande potencial de inserção em regiões que sofrem com o estresse hídrico, devido suas condições de adaptabilidade, qualidades e aplicações. Nesse sentido, este estudo objetivou identificar acessos de cártamo com potenciais de adaptações às condições edafoclimáticas norte-mineiras, visando fomentar um programa de melhoramento. Para isso, 10 acessos do cártamo foram avaliados por caracteres morfoagronômicos. Os caracteres avaliados foram a altura de plantas, matéria seca da parte aérea, diâmetro do caule, ramificação primaria e secundária, inflorescência, produção de grãos e a produção de óleo. Os dados experimentais foram submetidos à análise de variância, ao teste Scott- Knott, correlação linear de Pearson e agrupamento de otimização de Tocher. A herdabilidade (H²), os coeficientes de variação ambiental (Cve) e genética (Cvg) e a e relação Cvg/Cve foram estimados. Foi possível avaliar o potencial de produção das variedades de cártamo e obter a seleção das variedades de maior potencial produtivo para as principais características. Também foi possível selecionar os caracteres com maior potencial ao melhoramento genético. O cártamo pode ser inserido nas condições norte-mineiras e se tornar uma espécie de importância econômica.

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