Saffron (Crocus sativus L.) Adaptability Approaches to Climate Change

Flower initiation and flower emergence stages in saffron, which occur in around midsummer
and mid-autumn respectively, are influenced by increased temperatures due to
climate change. Heat stress causes abortion of flowers in the mid-summer and delays
flower emergence in autumn. Decreasing the amount of rainfall during the growing season
of saffron and the early end of vegetative growth of the plant in spring (reduction of corm
weight) are the other negative effects of climate change on saffron. Therefore, providing
strategies to enhance saffron adaptation to climate change is highly important. In this
regard, several experiments were performed in the climatic conditions of Khorasan
province, Iran. Application of organic mulch (wheat residue at the rate of 5 t ha-1) reduced
soil temperature (at the depth of ~15 cm), by 3.6 and 10.1 oC, compared with soil
tempreture in no-mulch treatment and air tempreture, respectively. Shading of saffron
fields using fiber material with polyethylene coating, can also reduce the soil temprature by
~ 4.8 oC, in mid-summer. Corm storage outside the soil under controlled conditions
(temperature of 25 oC, darkness and appropriate humidity) during the flower initiation
stage, and then planting them in soil is another possible strategy to reduce the effect of heat
stress on saffron. Howevre, in our experiment, the corms moisture was lost due to low
ambient humidity during storage, and reduced their flowering. Controlled and prudent
application of white slurry on the field surface, which reduces the entry of thermal energy
into the ground, can be considered as a possible strategy in the future studies. In areas
where the above adaptative strategeis are not effective due to heat intensity, saffron
production under controlled environment can be considered. Our reserches showed that
its possible to produce saffron under controlled conditions with higher yield and
acceptable quality than the traditional field production system. In addition, exprimental
results showed that application of superabsorbent polymer and increasing the amount of
soil organic matter, mainly by manure, are two practical ways to maintain soil moisture
and reduce the negative effect of lack of rainfall during saffron vegetative growth.