Evaluation of Freezing Tolerance of Hexaploid Triticale Genotypes under Controlled Conditions

Abstract

In order to evaluate freezing tolerance of different triticale (X Triticosecale Wittmack) genotypes, an experiment was carried out under controlled conditions in 2007 and 2008 at college of agriculture, Ferdowsi University of Mashhad. In this study seeven triticale genotypes , across six temperatures (0°C, -4°C, -8°C, -12°C, -16°C and -20°C) were evaluated within a factorial-completely randomized design with three replications. Plants were kept until 2 leaf stage in chamber with temperature of 20/15°C (day/night) and 12.5 h photoperiod. At the end of this stage, plants were under acclimation for three weeks. After exposing to acclimation freezing the cell membrane integrity was measured through electrolyte leakage (EL) and the lethal temperature (LT50) of samples was measured. After the exposure to freezing temperatures the samples were transferred to the greenhouse. Survival percentage, plant height, leaf area and number, chlorophyll content, and plant dry weight were determined after 3 weeks. Results showed that the effect of different freezing temperature and genotypes were significant on all plant characteristics. As temperature decreased, %EL of all genotypes was increased. Minimum and Maximum EL % in leaf and crown were observed at 0°C (21%) and -20°C (88.5%). 'ET-79-17' and 'Juanilo-92' genotypes showed the highest EL% (55.5% and 44.8%) and 'ET-83-20' the lowest EL% (47.3% and 41.2%) in leaf and crown. Dry weight and leaf area decreased by 48% and 42% respectively compared to non frozen control plants. ' genotypes showed the highest dry weight (83.8 mg) and highest leaf area (14.3 cm 2 ) respectively and 'ET-83-20' cultivar showed the lowest dry weight and leaf area (58.2 mg and 8.7 cm 2 ).

Chlorophyll Fluorescence-Based Studies of Frost Damage and the Tolerance for Cold-Induced Photoinhibition in Freezing Tolerance Analysis of Triticale (×Triticosecale Wittmack)

“…Due to the same mechanism, some breeding lines of triticale are considered to be freezing tolerant, and finally the large variation in freezing tolerance of triticale is observed (Yu et al. 2004, Nezami et al. 2010).…”

“…Thus, selection towards freezing tolerance in triticale seems to be very important for further enlargement of cultivation area. The choice of efficient freezing tolerance estimation method seems to be crucial, especially because contradictory results of genotypic freezing tolerance were reported when different freezing tolerance criteria were analysed in triticale (Nezami et al. 2010).…”

“…This may be connected with genetic structure of hexaploid triticale, where some chromosomes of wheat D genome, which contains genes important for winter hardiness, and some chromosomes of rye genome R are lost during the formation of composite genome (Dou et al 2006). Due to the same mechanism, some breeding lines of triticale are considered to be freezing tolerant, and finally the large variation in freezing tolerance of triticale is observed (Yu et al 2004, Nezami et al 2010. Thus, selection towards freezing tolerance in triticale seems to be very important for further enlargement of cultivation area.…”

“…Thus, selection towards freezing tolerance in triticale seems to be very important for further enlargement of cultivation area. The choice of efficient freezing tolerance estimation method seems to be crucial, especially because contradictory results of genotypic freezing tolerance were reported when different freezing tolerance criteria were analysed in triticale (Nezami et al 2010). A strong interaction between the freezing tolerance of the genotype and the environment was also observed in triticale (Hömmo 1994), thus the development of environmentally stable method is required.…”

Chemical composition of winter triticale grain depending on type of tillage in crop rotation

“…Triticale grain has a high nutritional value and is mainly used for feed purposes [2][3][4]. The use of triticale grain for food purposes is still being researched [5][6][7]. Therefore, the level of mineral components in triticale grain is important, as the unfavorable level may cause a decrease in the biological value of feed and adversely affect the metabolism of animals [8;9].…”