In potato cultivars, tuber yield is optimal at daytime temperatures ranging
from 14?22°C, with further increase in temperature, tuber production is
reduced or inhibited. Almudena Trapero-Mozos of the University of St. Andrew
in the UK aimed to identify quantitative trait loci (QTL) associated with
enhanced potato tuber yield.

A candidate
[www.isaaa.org] gene,
HSc70, was identified within the QTL intervals associated with elevated
yield in a hybrid diploid potato population. A particular HSc70 allelic
variant was then found to be linked to elevated yield in the population.
Expression of the allelic variant was much higher than others, especially
when exposed to moderately elevated temperature.

Analysis revealed a repeat element present in the promoter of the variant
allele, but not in other HSc70 alleles in the population. Expression of the
allelic variant under its native promoter resulted in enhanced expression at
elevated temperature. This leads to improved yield under moderately elevated
temperature.

These results identify the HSc70 expression as a significant factor
influencing yield stability under moderately elevated temperature.

[onlinelibrary.wiley.com]