Authors: DE VRIES D P; SMEETS L; DUBOIS L A M
Authors Address: INST. HORTIC. PLANT BREED., P.O. BOX 16, 6700 AA WAGENINGEN, NETH.
Title: HYBRID TEA ROSES UNDER CONTROLLED LIGHT CONDITIONS 4. COMBINING ABILITY ANALYSIS OF VARIANCE FOR PERCENTAGE OF FLOWERING IN F-1 POPULATIONS
Published in: Netherlands Journal of Agricultural Science, volumn 28, pages 36-39, (1980).
Abstract: " Hybrid tea-roses under controlled light conditions: 4. Combining ability analysis of variance for percentage of flowering in F1 populations.F1 populations of the Hybrid Tea-roses ‘Sonia’, ‘Baccara’, ‘Ilona’, ‘Prominent’ and ‘Zorina’ were grown in a growth room under 8 W m-2, 20.degree. C, 8 h. Inheritance of flowering ability under low irradiance was mainly controlled by additive gene action. ‘Prominent’ and ‘Zorina’ had a good general combining ability for flowering under low irradiance."
This is a very good article. The take home message that I got from it and the other related articles from similar work by these authors is that one can select seedlings that will continue to reliably flower under low light conditions. The reason they did this work is to select productive cut rose cultivars that bloom under the short day length and lower light intensities common in Holland greenhouses in the winter. All seedlings are from repeat blooming parents. However, under low light conditions many do not bloom well and produce a high proportion of blind shoots.
In another study they clonally propagated seedlings that bloomed under low light reliably and those that produced relatively more blind shoots under low light. They followed these plants for over a year using commercial cut flower conditions and learned that those selected to flower reliably under low light produced more flowers throughout the whole season and especially during the winter months.
What’s the take home message for us??? Perhaps we can grow our seedlings under lower light and reliably select for those that bloom and are more shade tolerant for the landscape or for indoor potted mini plants. From the authors’ work those clones that were propagated for simulated commercial production were more low light tolerant, but did just fine when in high light during the summer months. Since cut rose production is shifting to sunny South America and other regions close to the equator due to high fuel cost for heating greenhouses in the North and high labor costs in developed countries, the application for their work for the cut rose industry has become less of a concern.