|Gordon, Vanessa - UNIVERSITY OF WISCONSIN|
Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 2008
Publication Date: July 25, 2009
Citation: Gordon, V., Staub, J.E. 2009. Maternal Effects Supersede Nuclear Effects Conditioning Chilling Response in Cucumber (Cucumis Sativus L.). Journal of the American Society for Horticultural Science. Vol. 44(4):1056. Technical Abstract: Chilling damage can be a major determinant of yield reduction in cucumber production by acting to alter in sex expression, flowering dates, and plant development. Previous research determined that the ability of cucumber plants to withstand a chilling event (i.e., tolerance and susceptibility) is dictated primarily by maternaly inherited plastid genomes, or by nuclear factors contributed biparentally. To examine the modes of inheritence, exact reciprocal backcross populations were created by crossing 'Chipper' (tolerant plastid, susceptible nucleus) and M29 (susceptible plastid, susceptible nucleus). At the first true leaf, parents, reciprocal F1s, and reciprocal BC1-BC5 generations were chilled at 4 degrees C for 5.5 hrs under 270 umol PPFD. Results indicate that chilling response of individuals possessing 'Chipper' cytoplasm in any particular generation was not significantly different from the maternal plastid source. Additionally, lines within a plastid type did not differ significantly, despite unequal nuclear contributions. NC76 previously identified as a nuclear source of chilling tolerance performed intermediate to 'Chipper' and M29 in chilling response. F1s created by crossing tolerant and susceptible-plastic type BC5s crossed with NC76 performed as their plastid donors and were significantly different from one another, despite sharing heterozygosity for the nuclear chilling gene resident in NC76. Lastly, response of tolerant and susceptible BC5s (i.e., 'Chipper' plastid in the M29 background and M29 plastid in 'Chipper' background, respectively) could be immediately reversed upon reintrogression of the alternate plastid type. It is concluded that under the given chilling conditions, plastid effects determine tolerance or susceptibility in cucumber germplasm examined.