Identification of a number of superior and adaptive rapeseed (Brassica napus L.) lines in terms of different agronomic and phenological traits in Rasht

Cultivation and development of rapeseed to produce oil and livestock food and as a second crop after rice harvest to prevent loss of land productivity is of great importance. Therefore, the selection and identification of cultivars and lines with a short period of maturity with desirable agronomic characteristics and high yield add to its importance. In this regard, the present study was conducted to identify the superior and most adaptive canola lines in terms of various agronomic and phonological traits.

In the present study, 20 rapeseed lines along with Saffar and Dalgan cultivars were studied in a randomized complete block design with three replications in the research station of the Rice Research Institute of Iran in Rasht during the crop year of 2019-2020. The measured traits included stem diameter, number of branches, the lowest height of branches with pods, plant height, days to ripening, days to pods, days to flowering, days to emergence, grain yield, harvest index, biomass, one thousand seed weight, number of seeds per pod, number of pods per plant, and pod length. The Arunachalam ranking and GT-biplot analysis were performed to compare genotypes and identify the best genotypes in terms of all traits.

According to the results of ANOVA, different lines had significant differences in terms of all traits, which indicates the diversity of lines for these traits. In terms of the ripening period, the range of genotype variation was three days and ranged from 195 (in Saffar cultivar and SRL9820 line) to about 198 days (in SRL-98-15 line). In total, the highest amount of grain yield and biological yield (3773.30 and 12143.3 kg ha-1, respectively) and the highest number of pods per plant (209.1) were observed in the line SRL-98-17, and considering this line showed a short ripening period processing (196.67 days). Therefore, it could be introduced as the best line. All lines in terms of yield and other agronomic and morphological traits, were superior to the control cultivar Saffar (with a yield of 1621.67 kg ha-1). Also Delgan cultivar in terms of yield appeared superior to Saffar cultivar (290.2903 kg ha-1).

Based on the results of Arunachalam ranking and GT-biplot analysis, lines SRL-98-17, SRL-98-14, SRL-98-9, SRL-98-1, SRL-98-15, and SRL-98-12 had the highest ranks, respectively. They achieved to the highest position in terms of all phenological, morphological, and yield-related traits. Therefore, based on the results of the present study, they can be introduced as the most adaptive lines under mild and humid climate of northern of Iran.