Molecular examination and genotype diversity of vernalization sensitivity and photoperiod response in old and modern bre
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J. Crop Sci. Biotech. 2012 (December) 15 (4) : 259 ~ 265 DOI No. 10.1007/s12892-012-0077-z RESEARCH ARTICLE
Molecular Examination and Genotype Diversity of Vernalization Sensitivity and Photoperiod Response in Old and Modern Bread Wheat Cultivars Grown in Iran Mohsen Mohammadi1*, Davoud Torkamaneh2, Elham Mehrazar3 Molecular Genetics Unit, Cereals Research Department, Seed and Plant Improvement Institute, P.O. Box 4119, Karaj, Iran
Received: July 24, 2012 / Revised: August 11, 2012 / Accepted: September 24, 2012 Ⓒ Korean Society of Crop Science and Springer 2012
Abstract Understanding the genetic factors governing developmental patterns and flowering time in breeding materials is required for the development of new wheat varieties for a specific environment. Iran is among the largest wheat producers in the arid and semi-arid regions of the Middle East and North Africa. The wheat germplasm grown in Iran is either developed nationally or is introduced from the CIMMYT global wheat program. For decades, the wheat breeding program in Iran focused on generating new varieties better able to grow in the predominant Iranian climatic conditions such as humidity at the reproductive stage, high temperature during reproductive stages (terminal heat stress), moderate temperature during the cropping season, and high probability of frost damage during early stages of growth. There have also been sub-programs aimed at developing drought and salinity-tolerant wheat cultivars in Iran. Knowledge of cultivars' growth habits in Iran is currently limited to flowering in spring-sown nurseries. We identified allelic diversity in loci involved in vernalization response (Vrn) and photoperiod sensitivity (Ppd) in 60 bread wheat cultivars developed in Iran, CIMMYT, or ICARDA. This study revealed that the spring growth habit observed in most of the cultivars is conferred by a combination of recessive vrn-A1 and dominant Vrn-D1, Vrn-B1, and/or Vrn-B3 loci. This implies that most of the cultivars have minimal vernalization requirements for overwintering. Perhaps cold winters, even in the southern regions of Iran, provide sufficient vernalization conditions for cultivars possessing the recessive vrn-A1 allele. The germplasm investigated in this study revealed no evidence indicating selection for or against any specific Vrn and Ppd allele in our wheat breeding program. Key words : allele specific primers, molecular diagnosis, photoperiod, vernalization, wheat
Introduction Adaptation of wheat requires life cycle adjustments to environmental conditions determined, in part, by flowering and maturity (Cockram et al. 2007). Optimal fitness of developmental patterns to the environment is key for crop performance and yield potential (Richards 1996). Therefore, understanding genetic factors mediating developmental patterns and flowering in breeding materials is required for developing new wheat varieties for a particular environment. Developmental phases of wheat flowering is under the control of four genetic systems, including vernalization (Vrn) Mohs
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