Depending on mother corm size, the removal of extra lateral buds regulates sprouting mechanism and improves phosphorus acquisition efficiency in saffron (Crocus sativus L.)

Low P solubility in arid and semi-arid regions dominated by alkaline or calcareous soils is known as a main limiting factor for sustainable saffron (Crocus sativus L.) production. Hence, it may be necessary to consider efficient approaches for improving P uptake mechanism. The effects of lateral buds removal and mother corn size on daughter corms behavior, flower yield and P acquisition efficiency (PAE) were studied in saffron grown in a P-deficient soil in a two-year field experiment during 2017-2018 and 2018-2019 growing seasons. The 16 main plots [lateral bud removal (no removing lateral buds as control, keeping apical bud + removing all lateral buds, keeping apical bud + 1 lateral bud, and keeping apical bud + 2 lateral buds) x mother corm size (4.1-6.0, 6.1-8.0, 8.1-10.0, and 10.1-12.0 g)] and 2 sub-plots (first and second sampling) were conducted based on a randomized complete block design arranged in factorial-split with 3 replicates. The maximum leaf area, flower number, and dried stigma yield were observed by keeping 2 lateral buds on mother corm. By contrast, the minimum values were obtained in control treatment. Furthermore, keeping 1 or 2 lateral buds alleviated the adverse effects of small-sized mother corm on leaf and flower related traits. Large-sized daughter corms (> 10.0 g) constituted 25.0, 22.5, and 22.1% of the total number of daughter corms, respectively, when 0, 1, and 2 lateral buds were kept on 10.1-12.0 g mother corms. The highest P concentration in large-sized daughter corms (3.72 g kg(-1)) and PAE (38.89%) were obtained by keeping 2 lateral buds on 10.1-12.0 g mother corms, while the lowest values (2.66 g kg(-1) and 6.77%) were observed by planting 4.1-6.0 g untreated mother corms. It can be concluded that the sprouting mechanism in saffron is controlled by mother corm size. In sum, considering the cultivation of saffron in arid and semi-arid regions, selecting 10.1-12.0 g mother corms treated for keeping 2 lateral buds is recommended.