Effect of Temperature and Water Potential on Sprout Vigor of Potato (Solanum tuberosum L.) Seed Tuber

Abstract

A study was conducted to examine sprouting on potato seed tuber over a range of
different temperature and moisture conditions. The Experiment was conducted under controlled
environment conditions using a Terratec thermo-gradient table at the School of Agricultural
Science, University of Tasmania. The trial involved exposing seed tubers cv. Russet Burbank
(grade 40-60 g) sourced from one seed lot to three water potentials (-0.6 MPa, -0.02 MPa and
-0.01 MPa) at each of four different temperatures (10, 15, 20 and 25 °C). The growth medium
used in the trial was vermiculite (Grade 2, Australian vermiculite and Perlite Co-P/L). The
water potential treatments were prepared based on the relationship of water content and water
potential by Whalley et al. (2001). Four seed tubers were planted in each container filled with
growth medium at a 10 cm depth and covered by the growth medium before the containers
were resealed. Using a pseudo replication design with temperature as the block, the moisture
treatments were randomized within each temperature treatment with two replicate containers
for each treatment combination. The design therefore provided a total of 8 tubers for each
temperature and water potential combination, and a total of 24 treatment combinations
overall. An analysis of variance and least significant difference (LSD) procedure using SPSS
for windows version 14.0 was performed to determine the response of the tuber seeds to
temperature and moisture. Temperature and moisture significantly affected sprout growth
rate, assessed as the sprouting capacity of the tubers (FW sprouts per FW tubers). Sprouting
capacity of seed tubers increased with increasing temperature and water potential. There
was a significant interaction between temperature and moisture treatments on the sprouting
capacity (p<0.05). The differences between water potential treatments were greater at higher
temperature, with differences between sprouting capacity of tubers exposed to dry and wet
conditions particularly evident at temperatures of 20 and 25 ºC. Relation between the result
and risk in plant response to warmer climate as an impact of global warming is discussed.