Response of Saffron Ecotypes to Growing Season: Growth Analysis, Plant Nutrition, and Dry Matter Production

Development of saffron corm resources with higher ability to acquire nutrients and produce more dry matter may offer one solution to mitigate the yield loss problem in growing areas. In the present study, variability in growth, nutrition, and biomass production among saffron ecotypes grown for a two-year field experiment was investigated at Kerman, a semi-arid region of Iran, during the 2015-2016 and 2016-2017 growing seasons. The results indicated that the studied ecotypes significantly differed in the mentioned parameters and responded differently to growing seasons. High-agronomic performance (yield) and nutrient-efficient ecotypes, e.g. Ferdows, Sarayan, and Bajestan, accumulated more nutrients as a result of increased Relative Growth Rate (RGR) and Net Assimilation Rate (NAR) before the critical stage, resulting in higher dry matter production. In contrast, ecotypes with lower potential to acquire nutrients, e.g. Zarand and Torbat, had lower growth and dry matter. Further, the results showed that variation in nitrogen (N) concentration in corms and leaves was not significant, although significant variation existed in N uptake, N uptake efficiency, and N use efficiency. This can be due to variation observed in the ability of corms to utilize nutrients for dry matter production. Cluster analysis revealed the presence of highly efficient, moderately efficient, and inefficient ecotypes. Generally, the results indicated that ecotypes with higher growth rate before critical stage showed more potential to uptake and utilize nutrients to produce more dry matter, and exhibited more nutrients use efficiencies. Overall, this study suggested that the nutrient acquisition capacity of ecotypes, a desired feature associated with higher biomass production, can be an important factor in selection programs.