Evaluation of vernalization requirement in wheat inbred lines and cultivars under controlled conditions

An understanding of vernalization requirement is a prerequisite for the development of cold tolerant cultivars for high stress regions. Vernalization requirement in winter wheat (Triticum aestivum L.) has not been adequately addressed. Therefore, the objective of the present study was to understand how the vernalization dates are related to cold tolerance, phenological development and photosynthesis in four inbred lines (inbred line 1, 2, 3 and 4) and two wheat cultivars (Mironovskaya-808 and Pishtaz). These genotypes were subjected to vernalization temperature (5 C) on 30.11.2012, 17.12.2012, 09.01.2013, 13.02.2013 and 08.03.2013 as different vernalization dates. Control plants were grown under 25/20 C, day/night condition. Final leaf number was determined at intervals throughout the growth period to measure vernalization status. Number of days until heading was registered and lethal temperature (LT50) was determined. Photosynthesis rate was measured at the end of winter and flowering stages. According to the results the individual effect of genotype and vernalization date was significant on final leaf number, number of days until flowering and LT50. However, photosynthesis rate was just affected by vernalization date. In addition, interaction between vernalization date and genotype was significant on final leaf number, number of days until flowering and LT50. These results support the hypothesis that vernalization responses regulate phenological growth and affect cold tolerance through their influence on the rate of plant development.