Analysis of the effects of temperature and light after planting on bud blasting in Iris hollandica.

Abstract

in an initial experiment with several iris cvs bulbs were planted at 9-24 deg C, with 8- to 16-h photoperiods. A first flower was produced with all treatments but the percentage of second buds that blasted (i.e. aborted partially or completely) was greater at high temperatures and with short daylengths. In another experiment bulbs held at 30 deg followed by 9 weeks at 17 deg were forced in summer with 8 h of sunlight, extended daily by 0-12 h of weak incandescent light. The percentage of second buds that blasted varied between 50% with Dominator and 100% with La Marquette. The mean percentage of blasted buds became greater with longer photoperiods, possibly associated with the slightly higher temperatures; the number of days to flowering was not, however, affected. In a further experiment with various combinations of daylength (4-16 h light) and light intensity (50-100%) the blasting percentage was lower with longer daylengths and higher light intensities. In other experiments the effects of higher temperatures in increasing bud blasting were similar for day and night. Air temperature was of greater importance than soil temperature. Temperature sums for flowering and the critical period for bud blasting are also discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)