Investigation of Frost Stress Tolerance in Some Promising Rapeseed Genotypes

This study was conducted to evaluate freezing stress tolerance and identify tolerant genotypes among a number of rapeseed genotypes.

The experiment was carried out in the form of split plots based on randomized complete blocks with three replications in 1397 in a field with an area the 2000 square meters, in the form of autumn cultivation in the agricultural lands of Tikmehdash section of Bostanabad city. The main plot consisted of two dates of common cultivation (September 1) and delayed (September 16) and the sub-plot included 19 rapeseed genotypes. The mentioned genotypes are: SLM046, Opera, L963, Okapi, Nima, KH4, Talaya, L957, Ahmadi, KR18, L1009, Zarfam, Nafis, HW101, Licord, KS7, L14, SW101 and L1008.

The results of analysis of variance of yield per hectare under frost stress conditions showed that the effect of stress on the yield per hectare, it was significant at the level of 1% probability. The effect of genotype on plant height and yield per hectare was significant at the level of 1% probability and for 1000-seed weight at the level of 5% probability and was not significant for other traits. Genotype × planting date interaction was not significant in all traits. Also, the comparison of the mean of traits showed that Opera and HW101 genotypes had the highest value in plant height, 1000-seed weight and KS7 genotype in grain yield. Among the indices, MP, GMP, STI, HM and SNPI showed the highest correlation with grain yield under both stress and non-stress conditions and were introduced as the best indices to achieve high yielding and frost tolerant cultivars. Were. Based on the three-dimensional diagram, Opera, Licord, L1008 and Talaye genotypes were identified as the most ideal genotypes under frost stress conditions with above-average total yield under both stress and stress conditions as well as high SIIG values.

The results showed that Opera genotype with the highest amount of SIIG was one of the most tolerant genotypes and Nima genotype with the lowest amount of SIIG was one of the most sensitive genotypes to frost stress. The results also showed that the highest grain yield (kg.ha-1) in non-stress conditions was observed in KS7 genotype and the lowest grain yield was observed in KR18 genotype. Under frost stress conditions, the highest grain yield belonged to Opera genotype and the lowest grain yield belonged to KR18 genotype.