Yield and quality of pot marigold (Calendula officinalis L.) seeds depending on plant density in the field

Abstract

The field experiment (2011–2013) was focused on the assessment of the impact of
varied plant density (20, 40, 60, 80, and 100 plants·m-2) and row spacing (25 and 40 cm) on the
size and quality of seed yields in two pot marigold cultivars. The morphological traits of pot marigold
plants and elements of the yield structure were correlated primarily with the weather conditions
prevailing over the study years, plant density, and varietal properties, but they only slightly
depended on row spacing. The highest seed yield (1895 kg·ha-1) and crude fat yield (400 kg·ha-1)
were obtained in 2013 characterised by the highest precipitation rates during the period of intensive
plant growth, while the lowest values were noted in 2012 (1515 kg·ha-1 seeds and 297 kg·ha-1
fat), in which the lowest precipitation values during the vegetation season were reported. Increasing
plant density contributed to an increase in the plant height and a simultaneous decline in the
number of floral heads per plant and in the thousand-seed weight. The highest seed yields from
both pot marigold cultivars were achieved at a density of 60 plants·m-2. The content and quality of
fat were mainly determined by the weather conditions during the seed formation period. Favourable
water conditions combined with moderate temperatures promoted the accumulation of crude
fat and linolenic acid isomers (CLNA). The quality of the seeds differed between the studied cultivars:
‘Orange King’ seeds were characterised by a higher level of fat (21.1%), whereas the oil
from the ‘Tokaj’ cultivar had a higher proportion of CLNA (49.97%). Row spacing and plant
density did not affect the chemical composition of the seeds.