Identification of 'Ubá' mango tree zygotic and nucellar seedlings using ISSR markers

Abstract

Polyembryonic seeds are characterized by the development of over one embryo in the same seed, which can be zygotic and nucellar. The objective of this work was to identify the genetic origin, whether zygotic or nucellar, of seedlings of polyembryonic seeds of 'Ubá' mango tree using ISSR markers, and relating them with the vigor of the seedlings. Thus, mangos were harvested in Visconde do Rio Branco (accession 102) and Ubá (accessions 112, 138, 152 and 159), whose seeds were germinated in plastic trays filled with washed sand. Fifty days after sowing, seedlings from five seeds of each one of the accessions 102, 112, 138, 159 and from 10 seeds of the accession 152, were analyzed. These sseedlings were characterized and evaluated for plant height, stem circumference and mass of fresh aerial part and the most vigorous seedling was the one displaying at least two of these traits higher than the other seedlings from seed. Leaves were collected for genomic DNA extraction, which was amplified using seven ISSR primers previously selected based on the amplification profile and considering the number and resolution of fragments. Zygotic seedlings were found in 18 seeds, which were the most vigorous in six seeds. The results evidenced the existence of genetic variability in orchards using seedlings grown from seeds, because the farmer usually uses the most vigorous ones, assuming that this is of nucellar origin. These results also indicate that the most vigorous seedling are not always nucellar, inasmuch as of 20% of the total seeds evaluated, the zygotic seedling was the most vigorous.

Screening of Mango Landraces for Polyembryony and Confirmation of Seedling Origin using Microsatellite Markers

“…Cordeiro et al (2006) revealed that the zygotic plantlet was most vigorous and later confirmed this with RAPD marker. In accordance with this result, Rocha et al (2014) reported that the zygotic seedling need not be always weak. The zygotic plantlet will be vigorous in certain cases and grow healthy along with the nucellar plantlets.…”

Identification of zygotic and nucellar seedlings, originated by the largest embryo in mango seeds cv Ataulfo, using simple-sequence repeat (SSR)

“…The genetic variability found by the present study can also be due to the genetic origin of the propagated plant; two plants usually emerge from the planted seed, and nurserymen tend to choose the larger one assuming that the cutting is a "clone" of the progenitor. In the cv Rosinha, Cordeiro et al (2006) found that 90% of the more vigorous plants were of zygotic origin; eighteen seeds out of 30 in the cv Ubá contained zygotic embryos, and the zygotic seedling was the more vigorous in six of the 18 seeds (20%) (Rocha et al, 2014). In the present study, 15.27% of seedlings, originated by the largest embryo in the seed, were classified as zygotic.…”

“…Results found by Cordeiro et al (2006), Martínez et al (2012), and Rocha et al (2014) show that the zygotic embryo does not always degenerate and can give rise to the most vigorous plant of the seed.…”

“…In mango, more than two zygotic seedlings have been identified per seed (Martínez et al, 2012;Rocha et al, 2014); consequently, identifying the genetic origin of embryos 2 to 4 using SSR markers is advisable as an addition to existing information, to verify previously obtained data, and to identify a possible alternative apomictic route in addition to the nucellar.…”

Molecular Characterization of Seedlings Derived from Two Polyemberyonic Egyptian Mango Cultivars Using SSR Markers

“…The crosspollination nature and a wide range of common agroclimatic conditions have involved in a wide genetic diversity of mango (Abdalla et al, 2006). In polyembryonic cultivars, seedlings originate from somatic tissue and from a zygote, but differentiating between the two seedlings types can be confused (Rocha et al, 2014). Also, polyembryony makes breeding schemes complicated.…”