Study of growth indices and yield of double haploid lines of Camelina plant (Camelina sativa L.)

The camelina plant is a little-known plant Brassicaceae family. Camelina is an example of renewable vegetable oil that is considered a sustainable energy source. Seed yield and oil quality are the most obvious breeding objectives in the Brassicaceae family, while seed yield in agricultural plants, as their most complex trait, is influenced by a large number of physiological processes and the measurable expression is manifested in the physiological and morphological characteristics of the plant. Therefore, the analysis of physiological (growth) indicators is considered essential to understanding and interpreting changes in plant performance in response to environmental conditions. However, there is very limited information on the comparison of growth and functional traits of Camelina genotypes in the country. Therefore, the objective of this study was to compare the effects of physiological characteristics of 40 double haploid Camelina lines in the country.

In this study, 40 Camelina genotypes in terms of physiological traits and yield including leaf area index, crop growth rate, relative growth rate, net assimilation rate, specific leaf area, grain yield and oil yield were compared in a randomized complete block design with three replications in the research farm of Faculty of Agricultural Technology (Aburaihan), the University of Tehran, Pakdasht in 2020. It is worth mentioning that for measurement of the traits studied, the Soheil cultivar, which has long been grown both in the test area and in other parts of the country and is considered one of the well-known and widespread cultivar in the country, is considered as a control and other lines were compared with Soheil cultivar.

The results of the present study showed a significant difference between the Camelina lines in terms of physiological growth characteristics, the differences eventually led to significant differences in seed yield and thus had an impact on seed yield and oil content. This theme also shows and confirms the high and differential roles of genotype on camelina yield. In general, the results of this research showed that there is a positive correlation between the seed yield of camelina with the crop growth rate and the net assimilation rate, and there is a negative correlation with the specific leaf area at the 5% probability level. So, line 134 with the maximum leaf area index (2.34), and line 110 with the maximum growth rate (14.49) and net assimilation rate (8.13 g/m2 per day), in terms of the final grain yield were identified as the superior lines with 3178 and 3120 kg/ha, respectively. Also, the specific leaf area, which is directly related to the amount of light loss, was higher in low-yield genotypes than in lines 134 and 110.

The results of the present study showed the direct effect of seed yield on camelina oil yield. So that the greater compatibility of lines 110 and 134 with the studied culture environment has increased the dry matter accumulation and seed yield in the mentioned lines by increasing the plant growth rate and as a result has brought about a significant increase in seed oil yield in these lines. Since the purpose of cultivating Camelina oilseeds is, in addition to the seed harvest, to obtain oil of adequate quantity and quality, we can consider lines 134 and 110 as a whole as superior and promising double haploid lines, compatible with the climate conditions of the region.