Pt. Austin et al., SELF-INCOMPATIBILITY AND TEMPERATURE AFFECT POLLEN-TUBE GROWTH IN SUNDROP APRICOT (PRUNUS-ARMENIACA L.), Journal of horticultural science & biotechnology, 73(3), 1998, pp. 375-386
Comparison of fruit set after controlled self and cross pollination in
two New Zealand regions confirmed that 'Sundrop' apricot was effectiv
ely self sterile (fruit set <2%). Fluorescence microscopy showed that
tubes from 'Sundrop' pollen were self-incompatible and generally abort
ed in the upper part of the style. The strength of the inhibition reac
tion varied so that the tubes occasionally reached the ovary but none
penetrated ovules. Measurement of tube growth in 'Sundrop' styles at 5
degrees, 10 degrees, 15 degrees, 20 degrees and 25 degrees C showed t
hat temperature affected the rate with which self incompatible pollen
tubes were inhibited. Self tube penetration was strongest at 10 degree
s and 15 degrees C and weaker at higher temperatures. However, fertili
zation by 'Sundrop' pollen did not occur at any temperature and so the
need to cross pollinate this cultivar is not an interaction with low
temperatures during bloom.