Evaluation of winter oilseed rape genotypes for cold tolerance
2005
Pasban Eslam, Bahman | Mortazavi, Morteza | Sadeghi, Aitak
The injuries of cold stress on winter oilseed rape are caused by temperatures around 0؛C during early fall and spring and below 0 ؛C during winter. Oilseed rape plants with 6-8 leaves, 8 milimeter rosette diameter and 1.5 gram plant dry weight, indicate better tolerance against winter cold. The effects of planting date on winter survival and seed and oil yield of oilseed rape, are very important. The purposes of this experiment were studying of suitable plant phenotype for better cold tolerance in winter and evaluation oil and seed yield and its components in superior winter oilseed rape genotypes. The study was executed based on factorial design with two factors including planting date at two suitable ( 11 Sep.) and late seeding dates (26 Sep. in first year and 6 Oct. in second year) levels, and genotype including 6 superior winter oilseed rape genotypes, at three replication in two years. The experiment was carried out in Agricultural Research and Natural Resources Center of East Azarbaijan (46؛ and 2&rdquoE, 37؛ and 58&rdquoN) during 2003-2005. The results indicated that the genotypes in fall planting dates in comparison with 11 Sep. Plants, had less leaves, rosette diameter and dry weight at the time of reaching mean air temperature below oilseed rape base temperature (5؛C). As the genotypes at late planting dates did not have suitable rosette form during winter, therefore indicated more percentages of cold damages. Finally the genotypes at late planting dates, produce less seed and oil yield in both years. All of the studied genotypes indicated acceptable adaptation and yields. But the Elite, Okapi and Licord had higher yields in all planting dates and both years. It seems that the leaves numbers in plant, rosette diameter and plant dry weight measured at the time of reaching air temperature below base temperature, can be used for determining cold tolerant genotypes of winter oilseed rape and demonstrating the best planting date.
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