The Response of Promising Winter Rapeseed Lines to Delayed Cultivation

Some promising winter rapeseed lines were tested for their response to delayed cultivation. Accordingly, an experiment based on a split-plot design arranged in a randomized complete block design was applied during two cropping seasons (2020-2021 and 2021-2022) at the Research Station of Mahidasht, Kermanshah. Two Sowing dates September 20th and October 14th, along with 12 rapeseed genotypes were considered as main and sub-factors, respectively. Different agro-morphologic features including days to initiation of flowering, days to the end of flowering, days to physiological maturity, flowering duration, pod numbers per plant, plant height, seed per pod, sub-branches numbers, 1000-seed weight, and finally the grain yield have been measured. The results of two years of combined variance analysis showed a significant effect for the year regarding all evaluated traits, except for the sub-branch number. In the first and second years, the grain yield of rapeseed lines was equal to 3030 and 1661 kg ha-1, respectively. Combined analysis of variance results indicated that the sowing date × year interaction effect was significant for grain yield; therefore, the climatic conditions affected the response of rapeseed lines to the delayed sowing date. Also, significant effect was observed for sowing date regarding all investigated traits was significant, except for the seed numbers per pod. The rapeseed lines showed significant differences for pod numbers per plant, 1000-seed weight, plant height, sub-branch number, and grain yield. The results have also indicated a non-significant effect for genotype × sowing date interaction for grain yield. Therefore, the investigated lines did not show a different response to altered levels of sowing dates, and the lines that performed well under normal sowing date conditions performed well under delayed sowing date conditions as well. The highest grain yield was observed in Line No. 4 (WRL-17-98) with 3496 and 2162 kg ha-1 in normal and delayed sowing dates, respectively.