Evaluation of replacement corms growth criteria of saffron in response to different organic and conventional production systems

The use of corms with appropriate weight is one of the main factors in the flowering of saffron. Thus, the impacts of six organic (OS) and conventional (CS) production systems on the growth of saffron replacement corms was studied during one growth cycle from October 2015 up to May 2016 in this experiment. The experiment was conducted based on a randomized complete block design with three replications and six treatments including low, medium and high input organic systems as well as low, medium and high input conventional systems. A transition period of 24 months was considered in the chosen field before corm planting. Based on the results of an analysis of variance, the effect of experimental treatments was significant on the growth properties of most replacement corms (RC). The results of means comparison revealed that the differences within each organic or conventional system were insignificant but they were found to be considerable between the two OS and CS production systems. Total RC weight per clone and the number of flowering buds per RC in the OS production system were on the average 40% more than that of the CS production system. The amount of mean RC weight for OS and CS was 4.75 and 2.54g, respectively. The percent of RC with weight of less than 5g in the CS production system was higher than that of the OS production system (70 vs. 84%), while the percent of RC in 5-10g (13 vs. 14.5%) and more than 10g (3 vs. 15.7%) categories in the OS production system were more than that of the CS production system. The mean value of flowering buds had a significant correlation with the total RC weights per clone (.58**), mean RC weight (.64**), number of small RC (-0.57**) and number of large corm per clone (.61**). In addition, there was a significant correlation between the mean RC weight with the number of RC per clone (-0.55**), the RC weight per clone (.73**), the number of small RC (-0.89**) and the number of large RC per clone (.81**). Overall, the employment of OS had a significant positive effect on the growth of saffron replacement corms especially on mean corm weight and the number of flowering buds.