Growth and physiology of yarrow species 'Achillea millefolium' cv. Cerise queen and 'Achillea filipendulina' cv. Parker gold at optimum and limited moisture

• Published in: Australian Journal of Crop Science Vol. 5; no. 13; pp. 1698 - 1706
• Main Authors: Shad Khan Khalil, Rolston St Hilaire, Ahmad Khan, Abdur Rehman, John G Mexal
• Format: Journal Article
• Published: Lismore, N.S.W Southern Cross Publishers 01.12.2011
• Subjects: Effect of drought on; Experiments; Growth (Plants); Plants; Yarrow
• ISSN: 1835-2693

Appropriate management of a limited water supply would be an effective tool to reduce production costs, minimize nutrient leaching, and conserve water. Yarrow is considered a high value herbaceous perennial for landscape in United States, and have solid, matforming rhizome/root system with fine feathery leaves which make it drought resistant. However, little information quantifies the physiological performance of yarrow species under limited moisture and recovery from drought. Two yarrow species (Achillea millefolium cv Cerise Queen and Achillea filipendulina cv Parker Gold) plants were subjected to four irrigation intervals: irrigated daily (control), 3, 6 and 9 days under greenhouse conditions in 2004 and 2005. Irrespective of the species, the plants exposed to drought had lower predawn leaf water potential (pd), stomatal conductance (Sc), transpiration rate (Ts), cell osmotic potential (s), and relative water content (RWC) than controls. Leaf area (LA), leaf weight (LW) and root weight (RW) of the controls were over twice that of plants irrigated every 9 days in 2004 and over four times as high in 2005. Leaf area ratio (LAR) was lowest in the control and increased with each level of drought stress. Root-to-shoot dry weight ratio (RSR) of the control was highest and decreased with each stress level and lowest RSR was observed for plants irrigated every 9 days. Drought did not affect net assimilation rate (NAR). In both years, relative growth rate (RGR) of the control was twice as high as plants irrigated every 9 days. Both species performed better in irrigated conditions compared with drought stress. However, the production of larger leaf area (3209 cm2) heavier leaves (35.99 g) and better osmotic adjustment by the Cerise Queen specie in response to drought enabled it to deposit more solute and lowered leaf water potential without dehydration than Parker Gold, and thus may be grown successfully on limited moisture.