Physiology Study on Alstroemeria (Alstroemeriaceae) Hybrid, a New Cut-flower for the Brazilian Market G.M. Dias-Tagliacozzo1, A.F.C.Tombolato1 and I.F.M. Válio2 1Instituto Agronômico de Campinas, 1481 – P.O. Box 28 CEP 13001-970 Campinas, SP, Brazil 2Department of Physiology, University of Campinas Keywords: photoperiod, germination, flowering, vernalization. Abstract The market for Alstroemeria is growing in Brazil; however, production concentrates exclusively on imported Alstroemeria hybrids. These are limited in their cultivation to certain periods of the year, even in mountain regions. The aim of this work was to study environmental factors that could influence the germination, growth and flowering of a Brazilian cultivar, an unnamed Alstroemeria caryophyllaea hybrid that flourishes in tropical conditions. Seed germination of this cultivar is indifferent to light or dark. The rate of germination was different in seeds maintained at 25 oC and 17 oC, however the percentage of germination after 45 days was 88 and 82 %, respectively. A temperature of 30 oC partially inhibited this process; only 50 % of seeds germinated at this temperature. Rhizomes were maintained for 2, 4 and 8 weeks at 5 oC and 25 oC to evaluate the influence of vernalization. It was observed that although flowering occurred independently from the temperature, the percentage of flowering plants was higher at 25 oC (70%) comparing to 5 oC (20%). It appears that cold has a negative effect on flowering of this cultivar. Effect of photoperiod is qualitative in this cultivar. All plants flowered at both photoperiods, plants maintained with short days (8h) bloomed before plants maintained with long days (18h). INTRODUCTION The alstroemeria is an alternative crop for Brazilian floriculture. The exotic cultivars introduced show climatic limitations. Temperature and light are among the environmental factors affecting alstroemeria flowering. Healy and Wilkins (1982), suggested that temperature, specifically soil-temperature, is the main factor controlling alstroemeria flowering. Plants from rhizomes stored from 5 to 15 °C, flower continuously while storage from 20 to 25°C reduced flowering to 14 weeks. The other environmental factor that affect flowering of alstroemeria is photoperiod. The number of days to flower decreased as photoperiod increased (Healy and Klick, 1993) The aims of this work were to investigate the influence of light and temperature on the germination of seeds, rhizome vernalization and photoperiod on the flowering of a Brazilian alstroemeria species. MATERIALS AND METHODS The experiments were carried out in the glasshouse of the Departamento de Fisiologia Vegetal-Universidade de Campinas and Laboratories of the Instituto Agronômico de Campinas, with a diploid hybrid of Alstroemeria aff. caryophyllaea that flowers in tropical conditions (Fig. 1). Germination In all experiments the 20 seeds were sown in each of the 4 standard boxes on filter paper wetted with distillated water and kept in growth chambers. In the first experiment the seeds were kept at constant temperatures of 17, 25 and 30 °C. In the second experiment the seeds were sown at 25 °C in light or dark. And in the third experiment, seeds were stored in paper bag at 7 and 25 °C for four weeks. After this dry storage period, seeds were placed to germinate at 25 °C. The experiments were concluded when Proc. Vth IS on New Flor. Crops Eds.: A.F.C. Tombolato and G.M. Dias-Tagliacozzo Acta Hort. 683, ISHS 2005 287 the number germinated seeds became constant. Vernalization To evaluate the influence of vernalization in this hybrid, 60 fragments of 3 cm of rhizome (10 replications of one fragment per each of the 6 treatments) were maintained in wet vermiculite in standard box during 2, 4 and 8 weeks at 5 or 25 °C. After that, they were planted in pots filled with a mixture of soil and manure (3:1) and cultivated in greenhouse until flowering. The percentage of flowering plants was calculated after 23 weeks. Photoperiod Forty fragments of rhizomes (20 replications of one fragment per each treatment) were planted in plastic bag (2 liters) containing a mixture of soil and manure (3:1), and cultivated in a greenhouse. Plants were grown under daily 8 h light (SD- short day) and under18 h light (LD- long days). The plants were kept in these conditions until flowering. Short day was obtained by covering the plants with a black cloth. Conditions for long day were obtained by suplementing the natural photoperiod with incandescent lamps (53Wm2). During the development, plants height was measured from the surface of the pot to the top of the stem. The number of leaves, vegetative stem, floral stem, and floral bud per stem were counted. The percentage of flowering plants per treatment was calculated weekly during the 23 weeks. RESULTS AND DISCUSSION Germination The germination of this cultivar was indifferent to light; the percentage of germination was the same in dark or light. Germination started after 10 days, and 35 days later 95% germination was observed in both treatments. The rate of germination was different for seeds maintained at 25 °C and 17 °C, although the percentage of germination after 45 days was not statistically different. The temperature of 30 °C inhibit partially this process; only 50% of the seeds germinated at this temperature (Fig. 2). Pre-treatment of 7 °C enhanced germination (20%) when compared to 25 °C (5%) only at the beginning of the treatments (10 days). At the end of the experiment final percentage of germination reached 88% for both treatments (Fig. 3). Vernalization It was observed that flowering occurred independently from the rhizome vernalization time, 2 or 4 weeks, but the percentage of flowering was higher in plants which the rhizomes received treatment of 25 °C (70-75%) than in the treatment of 5 °C (20%) (Table 1). The rhizomes maintained in standard box did not survive more than 8 weeks in those conditions (5 or 25°C). For this cultivar, cold treatment had no effect in contrast to other cultivated in temperate climate, as observed by Healy and Wilkins (1979). Photoperiod The effect of the photoperiod was quantitative. Plants maintained in short days flowered earlier than plants in long days. After 13 weeks 90% of plants in SD had flowered against 20% in LD. However ten weeks later all plants flowered independently from the photoperiod (Fig. 4). The number of flowering stems was higher in SD, with an average of 1,9 stem/per plant at the 15th week, while LD showed an average of only 1 stem/plant. In the last evaluation (21 weeks) the average of flowering stems was 4,7 in SD and 3,2 in LD (Fig. 5). 288 Healy and Klick (1993) observed during autumn, that alstroemeria flowered faster and released more flowering stems than during summer. The authors correlated this fact to the low temperature effect in autumn. But during autumn the photoperiod is also shorter than during summer. This experiment was carried on for SD and LD under the same temperature, which shows that actually the photoperiod has more influence to the flowering than the temperature. The plant height and the number of stems, leaves and floral buds per stem were indifferent to the photoperiod. All these parameters presented similar results during all the period of observation. CONCLUSIONS The results obtained in these experiments can contribute to the knowledge of the flowering of this Brazilian diploid hybrid alstroemeria and to help the growers to cultivate this species throughout the year. These species from tropical origin can flower during all the year despite the soil temperature. The results presented here suggest that many native Brazilian species of alstroemeria and their diploid hybrids behave differently than those tetraploid hybrids cultivated now by the florists Literature Cited Healy, W.E. and Wilkins, H.F. 1979. Flowering requirements of Alstroemeria hybrida ‘Regina’. Hort Science, 14:395. Healy, W.E. and Wilkins, H.F. 1982. Responses of Alstroemeria ‘Regina’ to temperature treatments prior to flower-inducing temperatures. Scientia Horticulturae, 17:383-390. Healy, W.E. and Klick, S. 1993. Controlling shoot elongation of potted Alstroemeria. Acta Hort. 337:25-29. Tables Table 1 Effect of rhizome vernalization on flowering of Alstroemeria Hybrid. The rhizomes maintained in standards box did not survive after 8 weeks. Temperature °C Vernalization time (weeks) % of flowered plants 5 2 20 5 4 20 25 2 70 25 4 75 289 Figures Fig. 1. Alstroemeria aff. caryophyllaea 100 25 0C 90 // 80 17 0C 70 30oC // 60 50 // 40 % of germination 30 20 10 0 // 10 15 20 25 30 45 days Fig. 2. Seed germination of Alstroemeria aff. cariophilleae under different temperatures. 290 100 90 80 70 60 50 40 30 7 0C 20 controle 10 % of germination 0 5 101520253035days Fig. 3. Seed germination of Alstroemeria aff cariophileae at 25° C, after 4 weeks of pre- treatment at 7 or 25 °C. (control). 100 80 60 SD 40 LD 20 0 % flowering plant 13 15 17 19 21 23 weeks Fig. 4. Influence of photoperiod in flowering of Alstroemeria aff. Caryophillae. 5 4 3 2 SD 1 LD flowering sten/pot flowering 0 13 15 17 19 21 weeks Fig. 5. Influence of photoperiod in the number of flowering stems. 291.