Effect of Harvesting Time on Quantitative and Qualitative Characteristics of Safflower Cultivars Forage in Autumn Planting

In order to evaluate the quantity and quality of safflower cultivars forage in three forage harvesting times based on plant phenological stages, the present study has been conducted in a randomized complete block design with split-plot in time arrangements with three replications at the Seed and Plant Improvement Institute (SPII), Karaj, Iran, during 2018-2019 and 2019-2020 cropping seasons. The main factor includes three safflower cultivars (Goldasht, Golmehr, and Parnian), with three forage harvesting time (namely stem elongation, branching, and flowering stages) considered as the sub-factor. The effect of year only on plant height and water-soluble carbohydrates (WSC) has been significant (P≤0.05). The results show that the interaction effect of cultivar × harvesting time on the fresh forage yield, plant height, WSC, and neutral detergent fiber (NDF) has been significant (P≤0.01). The highest fresh forage yield (52103 kg ha-1) is obtained by harvesting the Golmehr cultivar at the beginning of flowering; however, the highest dry matter yield is observed in Golmehr and Parnian cultivars. The highest dry matter yield has been observed in the branching stage (11900 kg ha-1), with the crude protein content in this stage being 14.57%. In contrast, the maximum crude protein content is observed in the flowering stage (19.22%), even though the mean dry matter yield at this stage has been 9937 kg ha-1. The maximum and minimum RFV (130.3% and 92.3%) are recorded in the forage of Goldasht and Golmehr cultivars, respectively. Therefore, among the studied cultivars, Parnian, and among the growth stages, forage harvesting at the branching stage is introduced as the superior treatment to achieve maximum yield and quality of safflower forage.