Inheritance of self-compatibility in almond: breeding strategies to assure self-compatibility in the progeny.
To assure self-compatibility in the progenies, three different crosses were conducted for the first time in an almond breeding programme: self-pollination (266 descendants from 30 families), crosses between parents sharing an S-allele (108 descendants from five families) and crosses with homozygous self-compatible parents (62 descendants from five families). Depending on the cross, self-compatibility in the progenies was determined by observing pollen tube growth (by means of fluorescence microscopy), stylar S-RNases analysis or allele-specific PCR. The results obtained fit with the accepted hypothesis of inheritance of self-compatibility and the three crossing strategies used ensured 100% of self-compatible descendants. These strategies increase the efficiency of the breeding programme and avoid the laborious task of evaluating this characteristic. From the breeding point of view, self-fertilisation and crosses between relatives tend to produce inbreeding. Furthermore, these methods reduce the possibilities of choosing the parental combination. The use of homozygous self-compatible parents does not have any of these disadvantages. As far as we know, this is the first time that allele-specific PCR has been used for early selection of self-compatible seedlings. The advantages and disadvantages of the three methodologies used to determine self-compatibility are discussed.
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Departamento de Mejora y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas. P.O. Box 4195, E-30080, Murcia, Spain.
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D003433:Crosses, Genetic; D007178:Inbreeding; D027861:Prunus / Q000235:genetics*