M. C. R. Cordeiro

Identification of plantlet genetic origin in polyembryonic mango (Mangifera indica, L.) cv. Rosinha seeds using RAPD markers

Mango can be propagated by seeds or by grafting. For commercial purpose, grafting is the most appropriate method because it maintains the genetic characters from the propagated variety. To obtain grafted mango it is important to use polyembryonic varieties as rootstock since they produce a zygotic and many nucellar plantlets. The nucellar plantlets maintain the genetics of the mother-plant thus, are preferred for grafting since they supposedly give more uniformity to the orchard. In general, nurserymen use the most vigorous plantelet to graft, believing that they are nucellar. But, orchard disuniformities on height and yield are very common among mango trees of commercial orchards in Northeast region. The objective of this paper was to identify the genetical origin of plantlets from polyembryonic seeds of Rosinha variety using Random Amplified Polymorphic DNA (RAPD) markers. Moreover, the position of the zygotic embryo and the percentage of the vigorous zygotic and nucellar plantlets was also determined. It was obtained an elevated taxa of vigorous zygotic plantlets which possibly explains the disuniformity on height of trees at commercial mango orchards.

RAPD markers utilization and other parameters in the determination of mango hybrids genitors

Atualmente, o cultivo da mangueira (Mangifera indica, L.) e considerado um dos maiores agronegocios fruticolas brasileiros para o mercado externo. A selecao de cultivares com elevada qualidade de frutos e uma etapa fundamental para o sucesso deste negocio. O melhoramento genetico da mangueira, baseado em hibridacoes intervarietais, pode originar cultivares superiores aos padroes disponiveis no mercado, ofertando uma nova alternativa ao produtor. Hibridos de mangueira tem sido obtidos por meio de cruzamentos controlados ou abertos. Neste ultimo, e importante identificar o genitor masculino visando a obter a historia genetica da cultivar alem de ser importante no planejamento do melhoramento subsequente. Este trabalho apresenta um teste de paternidade, utilizando, entre outros parâmetros, marcadores RAPD (Random Amplified Polymorphic DNA), para estimar o genitor masculino de hibridos selecionados em uma area de cruzamento aberto contendo cinco cultivares de manga plantadas em alta densidade, no delineamento experimental do quadrado latino.