This study describes an efficient in vitro method using colchicinetreated triploid seedlings of Napiergrass and Pearl millet hybrids to produce hexaploid hybrids and their subsequent identification with flow cytometry. It also describes chromosome count and stomatal morphology and their use to ploidy analysis. Four-hundred and eighty triploid seeds, representing 12 different hybrids were sterilized and transferred to MS media to induce chromosome doubling. Surviving plants were analysed by flow cytometry. From six triploid (control) and hexaploid plants, the stomata sizes and frequency were analysed. Chromosome count was performed only in the plants identified as hexaploid. Seventeen plants were identified as hexaploid by flow cytometry analysis. Further confirmation of the hexaploid condition was performed with stomatal morphology (stomatal frequency reduction and stomatal length increase) and chromosome count (2n = 6x = 42). Chromosome doubling has numerous applications in Pennisetum breeding. It can be used to restore the fertility of interspecific hybrids and to improve seed size.The genus Pennisetum is one of the important genera of the family Poaceae. Pennisetum purpureum Schum. (Napiergrass) and Pennisetum glaucum (L.) R.Br. (Pearl millet) are important species widely used as forage. Pennisetum glaucum is a diploid species with 2n = 2x = 14 chromosomes and P. purpureum is tetraploid with 2n = 4x = 28 chromosomes (Martel et al. 2004). Napiergrass has been successfully crossed with Pearl millet to produce high quality and high yielding perennial interspecific forage hybrids (Hanna 1981). However, the sterility of this hybrid due to its triploid condition (2n = 3x = 21 chromosomes) has been pointed as a difficulty for its use in breeding programmes. The fertility of this hybrid can be restored with chromosome doubling. Colchicine is an alkaloid widely used for chromosome doubling and for the induction of polyploidy in plants (Pasakinskiene´2000). The technique of exposing explants to colchicine in vitro has been used in a number of cases (Kadota and Niimi 2002). Chromosome counts and stomatal morphology have been used routinely for polyploidy screening. However, these methods make the analysis of a great number of plants difficult and time-consuming. Flow cytometry represents a technology gain and has been increasingly used for highthroughput ploidy screening (Roy et al. 2001). This study describes an efficient in vitro method using colchicine-treated triploid seedlings of Napiergrass and Pearl millet hybrids to produce hexaploid hybrids and their subsequent identification with flow cytometry. It also describes chromosome count and stomatal morphology and their use for ploidy analysis. Plant materials and in vitro induction of chromosome doublingFour-hundred and eighty triploid seeds, representing 12 different hybrids (40 per hybrid), were sterilized and transferred to MS media to induce seedling development. The treatments (hybrids) have been arranged in a completely random design with four repetitions. Each...

Interactions between endophytic fungi (EFs) and their host plants range from positive to neutral to negative. The results of such interactions can vary depending on the organ of the infected host plant. EFs isolated from the leaves of some species of plants have potential for use as agents to inhibit seed germination and control invasive plants. The objectives of this study were to identify EFs present in the leaves of Copaifera oblongifolia and to evaluate the role of these fungi in seed germination and seedling development. A total of 11 species of EFs were isolated, which were identified using the internal transcribed spacers (ITS) sequence of the nuclear ribosomal DNA. The isolated species of EFs are generalists and probably are transmitted horizontally. Laboratory tests revealed that filtrates of these fungal isolates differently affect seed germination and seedling development of C. oblongifolia. The species Curvularia intermedia, Neofusicoccum parvum, Pseudofusicoccum stromaticum and Phomopsis sp. negatively affected seed germination, with N. parvum standing out for its negative effects, inhibiting seedling germination and survival in 89 and 222%, respectively. In addition, Cochliobolus intermedius negatively affected seedling development. Thus, the combined use of N. parvum and C. intermedius, or products from the metabolism of these microorganisms, in the control of invasive plants deserves attention from future studies.