Effect of organic fertilizers and mother-corm size on flower and corm yield of saffron (Crocus sativus) in the first year

This study was conducted to study the effect of mother-corm size (0 to 4 g, 4.1 to 8 g and 8.1 to 12 g) and different organic fertilizers (cow manure, humic acid (Humax® 95–WSG), an organic-mineral-based emulsion (Omic®) and unfertilized control) on flower and corm yield of saffron. The experiment was conducted as RCBD with factorial structure and three replications in the Research Complex of Medicinal Plants, ACECR of Southern Khorasan Province, Iran in 2017-18. Studied traits were stigma dry weight, flower dry weight, number of flowers, number of buds and bud dry weight, total number of corms and total weight of corms. According the results, mother-corm size factor significantly affected these traits. The highest and lowest amount of mentioned traits were obtained in big- and small-sized corms, respectively. Stigma dry weight in big-sized corm treatment with 82.22 mg.m-2 was about 190 times bigger than small-sized corm treatment. In addition, the highest number (466.36 corms.m-2 ) and weight (936.55g.m-2) of daughter corms belonged to mother-corm size between 8.1 to 12g. These results justify bearing the cost of providing big (over 4 grams) corms in saffron cultivation. Evaluating the main effect of nutrition factor revealed no significant impact on most studied traits. Comparing the slope of linear regression between stigma dry weight and corm size showed that the highest yield increasing happened in Omic treatment (12.91 mg in exchange for one unit of mother corm weight increasing). These results clearly show that despite significant effect of mother-corm size on yield of saffron, using organic fertilizers has no significant effect on these traits in the first year. However, using organic fertilizers might have some positive effects in the next coming years that needs to be studied.