Yield and Yield Component Response of Eight Potato Genotypes to Water Stress

The differential tolerance to moisture stress among potato (Solanum tuberosum L.) genotypes may be associated with differences in sensitivity during the ontogeny of yield development. This study was undertaken to determine the effect of a wide range of moisture stresses on the yield and components of yield of eight genotypes (‘Acadia Russet’, ‘Bintje’, ‘Jemseg’, ‘Kennebec’, ‘Raritan’, ‘Russet Burbank’, ‘Sable’, and ’Shepody’). The genotypes were subjected to three levels of soil moisture tension in 1983 (−30, −60, and −90 kPa) and four in 1984 (−30, −60, −90, and −120 kPa) at Vauxhall, Alberta on a Cavendish sandy loam (Brown Chernozemic) (fine-loamy, mixed, frigid Ultic Haploxeralf). A mathematical model based on the method of path analysis was used to study the relationship between the components of yield and the overall response of the final tuber yield to moisture stress. Moisture stress treatments caused marked (P < 0.01) reductions in marketable yield, tuber number per stem and average tuber weight. Mainstem number was not affected. The genotypes ✕ stress interaction was significant (P < 0.05) in an analysis of variation (ANOVA) carried out over 2 yr. While analysis of the yield data using the model demonstrated that in general genotypes are very sensitive to moisture stress at both tuber initiation and at the tuber sizing growth stages, the greatest variability amongst genotypes in response to stress occurred at tuber sizing. Shepody, Russet Burbank, and Sable showed a strong sensitivity to stress in the tuber initiation phase while Jemseg, Acadia Russet, and Kennebec were more sensitive at tuber sizing. The study demonstrates differences in the structure of the response of the genotypes to moisture stress, measured in terms of the components of tuber yield, and indicates the importance of this information to ensure efficient moisture management. LRS contribution 3878763.