GENETICS OF LATE BLOOMING IN ALMOND

Almond is the earliest blooming fruit species. This has restricted the economic growing of almond to frost-free regions. Most almond breeding programmes are trying to develop later blooming cultivars in order to avoid frost damage, by delaying bloom until after the probable time of occurrence of frosts when temperatures are higher and more favourable for pollination and fertilization. Blooming time is generally considered to be inherited quantitatively, but the study of the progeny ‘D-3–5’ x ‘Bertina’ shows that, in this cross, a single dominant locus (Lb) determines very late blooming. Modifier genes, inherited quantitatively, affect the expression of this major gene.