Número de sementes em frutos e frequência de híbridos obtidos de cruzamentos com a tangerina IAC 2019Maria

Abstract

In the Citrus Breeding Program of the Sylvio Moreira Citriculture Center of the Agronomic Institute (IAC), a cultivar was developed, the IAC 2019Maria mandarin, from the cross between the tangor Murcott IAC [Citrus sinensis (L.) Osbeck x C. reticulata Blanco] and Pera IAC sweet orange [C. sinensis (L.) Osbeck]. The present study aimed to evaluate the number of seeds in fruits of the tangerine cultivar IAC 2019Maria and to identify zygotic embryos and possible triploid plants from crosses between IAC 2019Maria mandarin and Pera IAC sweet orange [C. sinensis (L.) Osbeck] and Ponkan mandarin (C. reticulata Blanco), IAC 2019Maria mandarin in open pollination and self pollination. For this, the flowers of IAC 2019Maria were self-pollinated, pollinated with pollens of Pera Sweet orange and Ponkan mandarin, and only emasculated. The pollen of the varieties tangerine IAC 2019Maria, Ponkan mandarin and Pera Sweet orange were evaluated for their viability and germination, and the embryos were identified using microsatellite molecular markers and ploidy was evaluated by flow cytometry. The results of the treatment without pollination suggest that the variety does not produce parthenocarpic fruits, but is self-compatible and, in this case, there is a reduction in the number of seeds per fruit. Pollen viability analyzes showed that all varieties had high values of average percentage of viable pollens. The genotyping results using microsatellite molecular markers, showed that, 100% of all populations consist of zygotic embryos, suggesting that the IAC 2019Maria mandarin is a low polyembryonic plant, which can be widely used in breeding programs. The analysis of the ploidy of the plants allowed the identification of a triploid plant obtained from aborted seed from crossing with Pera sweet orange and two tetraploids, one from crossing with Pera orange and one from self-pollination.