Sexual polyembryony in almond

Abstract

Multiple embryos within the same seedcoat occur spontaneously in certain almond [P. dulcis (Mill.) D.A. Webb] cultivars including 'Nonpareil' and 'Mission'. Seedlings from the same polyembryonic seed are frequently viable, though one of the seedlings often shows weak growth and develops poorly. These dwarf seedlings have previously been reported as haploid. In this work, we have characterized several seedlings from 'Nonpareil' polyembryonic seed, including their germination and later growth. Isozyme and simple sequence repeat markers were used to analyze seedling genetic structure. In addition, individual mitotic karyotypes were determined following root-tip staining. The percentage of twin embryos showing aberrant growth was approximately 30%, with mortality rates of about 90%. The majority of these aberrant seedlings appear to be aneuploids. Most secondary embryos appear to be derived from the primary embryo following normal fertilization.

Studies on the early development of zygotic and synergid embryo and endosperm in polyembryonic rice ApIII

“…A similar phenomenon has been reported in Prunus dulcis in the study of Martínez-Gó mez and Gradziel (2003), who found that the percentage of twin-embryos showing aberrant growth was approximately 30%, with mortality rates of about 90%. And via phenological, molecular and cytological analysis, they corroborated that most of the aberrant seedlings appeared to be aneuploids, rather than haploids as suggested by previous researchers.…”

Molecular polymorphisms in Palestinian Figs (Ficus carica L.) as revealed by Random Amplified Polymorphic DNA (RAPD)

“…Biochemical markers like isozymes have also been used for varietal recognition, nevertheless their use is limited due to their low variation in a given species and small number of loci that can be analyzed by conventional staining methods [22]. Furthermore, in some cases, isozyme polymorphism is influenced by environmental conditions [1].…”

Polyembryony in Maize: A Complex, Elusive, and Potentially Agronomical Useful Trait

“…Similar results were obtained by Andrade-Rodriguez [76] who used RAPD markers for identification of zygotic and nucellar seedlings in polyembryonic Citrus reshni and reported that it was possible to identify both types of seedlings. By contrast, Martínez-Gómez and Gradziel [31] analyzed the genetic structure of almond seedlings from mono-and polyembryonic seeds and found that the seedlings have a similar genetic composition in both types of embryos. It was also mentioned that variation of polyembryony may be affected by a type of pollinator, available pollen amount, plant nutrition, environment temperature, soil moisture and temperature, and air velocity.…”

“…Plants from the same polyembryonic seed often are viable, although some of the plants may show a weak development of their leaves [31]. Andrade Rodríguez in 2005 [76] found that the environmental conditions during the growing season of Citrus volkameriana affected PE frequency; in addition, the fruit morphological characteristics do not indicate the PE frequency.…”