Abstract The propagation of guabijuzeiro (M. pungens) by seed is originating plants with high genetic variability and a long juvenile period. Therefore, the objective was to study the multiplication and rooting in vitro of guabijuzeiro in order to get information to enable the clonal propagation. In the multiplication, apical and nodal segments were used, taken from in vitro plantlets, combined with 6-Benzylaminopurine (BAP), naphthaleneacetic acid (NAA) and gibberellic acid (GA). In the rooting, NAA and IBA (indolebutyric acid) were used. The results showed that in the multiplication there was superiority in media with BAP, while rooting was not satisfactory in media with NAA or IBA. Thus, it is possible to multiply M. pungens in vitro using BAP phytoregulator in the multiplication stage. However, the rooting stage needs more tests to induce the production of roots and facilitate acclimatization of the plants obtained in vitro.

RESUMO O caquizeiro é uma planta muito complexa na questão de sua biologia floral, já que pode apresentar três tipos de flor (feminina, masculina ou hermafrodita) ou apenas flores femininas, como no caso das cultivares comerciais. O objetivo deste trabalho foi estudar o período de florescimento, os tipos de flores e estimar a viabilidade dos grãos de pólen em nove cultivares de D. kaki e em D. virginiana. As cultivares Pomelo e Rama Forte foram precoces para o início do florescimento. A cultivar Pomelo e a espécie D. virginiana apresentaram produção de flores masculinas, com pólen viável. As nove cultivares de D. kakiestudadas apresentaram produção de flores femininas (também masculinas em Pomelo) como esperado em cultivares comerciais. Porém a cultivar Mikado apresentou, ao final do florescimento, flores com produção de pólen viável, o que ainda não havia sido relatado. A viabilidade dos grãos de pólen, em geral, foi acima de 90% para as cultivares Pomelo e Mikado, e para D. virginiana.

ABSTRACT Persimmon tree is a very complex plant regarding floral biology, because it can present three types of flower (female, male or hermaphrodite) or only female as in the commercial cultivars. The objective of this research was to study the flowering period, flower types and to estimate pollen grains viability in nine D. kaki cultivars and in D. virginiana. Cultivars Pomelo and Rama Forte were the earliest for flowering beginning. Cultivar Pomelo and D. virginiana produced male flowers with viable pollen. The nine studied D. kaki cultivars presented females flowers (also male in Pomelo) as expected in commercial cultivars. Unexpectedly, cultivar Mikado presented male flowers with viable pollen at the end of the flowering period, what had not been previously reported. Pollen viability was generally over 90% for Pomelo, Mikado and D. virginiana.

The aim of the present study was to evaluate the possible effect of environmental factors on meiosis, meiotic index, pollen viability and in vitro germination of pollen from stock plants of the rootstocks Trifoliate, 'Swingle', 'Troyer', 'Fepagro C13', 'Fepagro C37' and 'Fepagro C41' grown in a protected environment in comparison with stock plants grown in the field. The results showed that values for the characteristics analyzed in 2008, 2009 and 2010 were always higher in the field than in the greenhouse conditions. In the field, the average of normal meiotic cells was 60.05%, 44.44% and 60.12%, respectively, and in the greenhouse, 52.75%, 30.95% and 52.82%, respectively. Mean pollen viability in the field was 90.28%, 56.23% and 74.74%, and, in the greenhouse, 64.25%, 41.41% and 66.71%, respectively. As temperature oscillations were higher in the greenhouse than in the field, we suggest that this negatively affects the reproductive characteristics analyzed.