Industrial Crops and Products 49 (2013) 177–187 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journal h om epage: www.elsevier.com/locate/indcrop Relationships between seedling establishment and soil moisture content for winter and spring rapeseed genotypes Hamid Jabbari a , Gholam A. Akbari a , Nayer A. Khosh Kholgh Sima b,∗ , Amir H. Shirani Rad c , Iraj Alahdadi a , Ali Hamed a , Mehran E. Shariatpanahi b a Department of Agronomy and Plant Breeding, College of Abureiyhan, University of Tehran, Pakdasht, Tehran, Iran b Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj, Iran c Seed and Plant Improvement Institute (SPII), Karaj, Iran a r t i c l e i n f o Article history: Received 17 February 2013 Received in revised form 24 April 2013 Accepted 26 April 2013 Keywords: Germination rate Principal component analysis Rapeseed genotypes Seedling establishment a b s t r a c t Rapeseed cultivars are important for edible oil production under semiarid area regions in Iran. However, germination and seedling establishment of rapeseed cultivars are the critical steps in successful produc- tion of this oil crop plant that are not well understood. The objective of this study was to evaluate the effect of low soil moisture on emergence and seedling establishment of 24 rapeseed genotypes includ- ing 13 cultivars and 11 doubled haploid lines. A pot experiment was conducted in a greenhouse using a factorial experiment based on a completely randomized design with three replications. The genotypes were evaluated under different soil field capacity (FC) levels (80%, 50%, 30% and 20% FC). Decreasing the soil moisture content from 50% to 20% FC resulted in reduced overall final emergence from 94.3% to 82.7%. Significant differences were observed among genotypes under different soil moisture levels for all studied characters. Seedling vigor index and shoot growth of the tolerant genotypes were signif- icantly higher under lower soil moistures levels. Studies on identification indices of drought resistance by principal component analysis (PCA) indicated that germination rate and final emergence were most important and better indicators of establishment in rapeseed. Cluster analysis and PCA method separated the genotypes into four groups. Genotypes in group I had the greatest tolerance, cluster II the intermediate tolerance, and clusters III and IV had the least tolerance to low soil moisture. In response to low soil mois- ture, cluster I (included GKH2005, Opera and Okapi) showed higher final emergence, rapid emergence, strong seedling vigor, and maximum shoot growth. On the other hand, cluster II (included DH1, DH3, DH4, DH5, DH7, DH8, DH9, DH10, DH11 and DH13) showed high coefficient of germination rate. Cluster III (included Cooper, SLM046, Lilian, Billy and Karun) had greater root length, cotyledon length and width, and root-to-shoot length with high mean time to germination whereas decreasing soil moisture resulted in severe reductions of final emergence and germination rate compared with those observed for 80% and 50% FC. Also, cluster IV (Included Adriana, Oase, Savanah, Triangle, Tasilo and DH6) had lower final emergence, delayed emergence, low growth potential, and high sensitivity for shoot and root growth. The results suggest that the genetic diversity within cluster I could be used for crop breeding programs and increasing the cultivation area in arid and semiarid regions of Iran. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Drought is one of the major abiotic stresses, which adversely affects crop growth and is a global issue to ensure survival of agri- cultural crops and sustainable food production (Jaleel et al., 2007). Iran contains both arid and semiarid regions and drought stress is ∗ Corresponding author at: Agriculture Biotechnology Research Institute of Iran (ABRII), P.O. Box 31535-1897, Karaj, Iran. Tel.: +98 9123898062; fax: +98 26 32704539. E-mail addresses: ksima@abrii.ac.ir, a.khoshkholghsima@yahoo.com (N.A. Khosh Kholgh Sima). one of the major environmental stresses restricting crop production in the country. Water stress is considered as important limiting factor at the initial phase of plant growth and seedling establishment (Devane, 2009). Drought may delay the onset, reduce the rate, and increase the dispersion of germination events; leading to reductions in plant growth and final crop yield (Omidi et al., 2009). Rapeseed (Brassica napus L.) is one of the most important indus- trial crops in Iran. One of the major challenges for the production of rapeseed in Iran is the lack of uniform stand establishment of the plants due to poor weather and dry soil conditions (Mwale et al., 2003). Worldwide rapeseed production is approximately 62.4 mil- lion tons and covers a total area of 33.6 million hectares (FAOSTAT, 0926-6690/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2013.04.036