De. Kester et al., IDENTIFYING POLLEN INCOMPATIBILITY GROUPS IN CALIFORNIA ALMOND CULTIVARS, Journal of the American Society for Horticultural Science, 119(1), 1994, pp. 106-109
Six cross-incompatibility groups, which contain most of commercially i
mportant California almond cultivars [Prunus dulcis (Mill.) D.A. Webb,
syn. Prunus amygdalus Batch], and their self-incompatibility (S) alle
le genotypes are identified. Incompatibility groups include 'Mission'
(S(a)S(b)), 'Nonpareil' (S(c)S(d)), and the four groups resulting from
the 'Mission' X 'Nonpareil' cross: (S(a)S(c)), (S(a)S(d)), (S(b)S(c))
, and (S(b)S(d)), as represented by 'Thompson', 'Carmel', 'Merced' and
'Monterey', respectively. All seedlings from the 'Mission' X 'Nonpare
il' cross were compatible with both parents, a result indicating that
these two cultivars have no alleles in common. Crossing studies suppor
t a full-sib relationship for these progeny groups and the origin of b
oth parents from common germplasm. Cultivars in these six groups accou
nt for almost-equal-to 93% of present California production, a result
demonstrating a limited genetic base for this vegetatively propagated
tree crop.