Response of plotted Alstroemeria to different growth retardants under protected conditions

Various concentrations of Alar (Daminozide), Chlormequat (Cycocel) and Paclobutrazol (Cultar) as spray, drench and combination of both drench and spray applications were tried on two cultivars of pot grown alstroemeria to study their effect on plant height, spread, and other flowering parameters in a factorial completely randomised block design under glasshouse conditions at Mashobra which were evaluated during two successive flushes in the year 2003–2005. Both the cultivars viz Selection No-14 and Riana responded favourably to retardant treatments. A height reduction of 31.5 per cent in the first flush was recorded with Alar (1500 ppm) spray whereas a combination drench and spray application of Alar (1500 ppm) resulted in 28 per cent height reduction in the second flush. Cultivar Riana in the second flush resulted in maximum height reduction and also produced maximum spread. Cultivar Selection No-14 took minimum days to bud formation, produced greater number of cymes per inflorescence in second flush and responded with a better pot presentability than cv Riana which remained in flowering for maximum duration in both the flushes. Significant reduction in days to bud formation was recorded with PP₃₃₃ (50 ppm) drench and spray in the first flush. A marked positive effect of PP ₃₃₃ (50 ppm) drench and spray along with Alar (1500 ppm) drench and spray was observed on number of cymes per inflorescence in the first flush whereas in the second flush, Cycocel (1500 ppm) drench and spray resulted in maximum number of cymes per inflorescence. All the treatments significantly increased duration of flowering and pot presentability in both flushes, with spray application of Alar (1500 ppm) coupled with drench and spray application of Cycocel (1500 ppm) and PP₃₃₃ (50 ppm) producing the best results.