Selection of fenugreek (Trigonella foenum-graecum L.) landraces for fall planting and freezing tolerance

Cultivation of medicinal plants, such as fenugreek, is important for producing healthy food and preparing raw materials for herbal medicines. Determining the appropriate planting date and tolerance of fenugreek to low temperatures can help to gain more economic yield. The effects of cold and fall planting on the Iranian fenugreek (Trigonella foenum-graceum L.) landraces were evaluated under controlled and field conditions in two years (2013-2015). Ten fenugreek landraces including Azari, Ardestan, Tall, Dwarf, Shiraz, Shirvan, Mashhad, Neyshabour, Hamedan, and Hendi landraces were planted on five planting dates (September 14, October 15, and November 14 in 2013; March 6 and April 4 in 2014). These landraces were also planted on four planting dates (September and October in 2013; March and April in 2014) in pots and were transferred to a thermogradient freezer to apply frost temperatures (-6oC, -9oC, -12oC, and -15oC). Four landraces including Dwarf, Shirvan, Mashhad, Neyshabour landraces were planted on five planting dates similar to the first year in the second year. Shirvan landrace showed more tolerance to freezing temperatures. Evaluation of survival rate showed that the controlled grown landraces had higher survival rates than the field-grown landraces. Mashhad (55%) and Shirvan (44%) had the highest and lowest yield reduction rates as a result of delaying the planting date from September to April. The branch number/plant in the first year of the field experiment and 1000-seed weight (TSW) in the second year had the most important impact on the seed yield. The most suitable sowing dates for the highest seed yield were October 15 and November 14. Shirvan landrace had the highest seed yield in all the planting dates in both years, and it can be recommended for cultivation in the regions.