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.