The influence of nitrogen fertilization on growth, flowering and keeping quality of alstroemeria 'carmen' and 'marina'
The study was conducted in Limuru from June to November, 1990, to investigate the influence of nitrogen fertilization on growth, flowering and keeping quality of Altroemeria 'Carmen' and 'Marina'. The number of total shootS/M2 increased significantly with application of nitrogen in 'Carmen' but the increase was not significant in 'Marina'. The average fresh weight of 'Carmen' flowering and vegetative shoots increased significantly with application of 117 kgN/ha. In' Marina', the average fresh weight of vegetative shoots increased slightly with nitrogen application but that of the flowering shoots increased significantly with application of 78 kgN/ha then decreased with higher nitrogen application. The average length of 'Carmen' vegetative and flowering shoots increased significantly with application of 156 and 117 kgN/ha, respectively. In 'Marina' the average length of vegetative and flowering shoots increased with application of 39 and 78 kgN/ha, respectively, but higher nitrogen fertilization decreased it significqntly. The thickness of both vegetative and flowering shoots of 'Carmen' was not significantly affected by nitrogen application. The vegetative shoots of 'Marina' had a similar trend but flowering shoots from plants fertilized with 39kgN/ha were significantly thicker than those from other nitrogen treatments. Nitrogen fertilization did not influence the number of leaves on flowering and vegetative shoots in both 'Carmen' and 'Marina'. The number of flowering shootS/M2 increased significantly with nitrogen application in 'Carmen' but slightly in 'Marina'. The percent of flowering shoots in 'Carmen' increased significantly with nitrogen fertilization but in 'Marina', it was not affected. Nitrogen fertilization did not affect onset to flowering of either 'Carmen' or 'Marina'. However, the number of cymes per inflorescence increased slightly with application of 156 kgN/ha in 'Carmen' and 39 kgN/ha in 'Marina'. Nitrogen concentration in leaves and stalks of both 'Carmen' and 'Marina' increased with increased nitrogen fertilization. It was highest in young leaves, intermediate in old leaves and lowest in stalks. Leaf chlorophyll content of cutflowers after harvest, on seventh and fourteenth day in vase remained high with application of 156 and 117 kgN/ha in 'Carmen'and 'Marina', respectively. There was a more rapid leaf chlorophyll breakdown of cutflowers in both cultivars during the first week than.the second week in the vase especially those from plants treated with high nitrogen levels. The average number of days to complete leaf yellowing in both cultivars increased signficantly with nitrogen fertilization. The average number of days to half petal fall in 'Carmen' increased significantly with nitrogen application, but in 'Marina', it increased slightly. In 'Carmen', split nitrogen applications did not affect shoot growth, flowering, cutflower qual ity and keeping quality. However, 'Marina' plants fertilized with most nitrogen levels had more leaves on flowering shoots when nitrogen was applied in four splits than two splits. 'Marina' cutflowers from plants fertilized with 39 and 78 kgN/ha in four splits interval lasted longer before complete leaf yellowing in vase than those fertilized in two splits.