ECOPHYSIOLOGICAL STUDIES OF ASPARAGUS (Asparagus officinalis L.) IN THE HUMID TROPICS

The success of asparagus plantation in Indonesia still being questioned by many business people. The failure in growing asparagus was mainly due to lack of knowledge for culturing this plant. For example, many farmers in Indonesia used unsuitable cultivar, and also believe that asparagus plantation will be successful only in high altitude. It is necessary, therefore, an effort to provide actual information about growing asparagus in the humid tropics area. The important information needed at the current stage are the suitability of cultivar for Indonesian environmnt, and also the relationship between environmental factors with plant growth performance. This research was conducted from July 1996 to November 1997. Thirteen cultivars from Taiwan, California and New Jersey were planted in three different altitudes, i.e. Talang Kering (20 m), Kepahiang (500 m) and Curup (l050 111) all located in propinsi Bengkulu. In each location the treatment were arranged in Randomized Completely Block Design with four replication. All the treatments were randomly allocated in each replication. Climatic variable measured were sun radiation, eir temperature, relative humidity, and rainfall during the early plant growth. The early plant growth variables were plant height, number of shoot, root and bud, plant fresh weight and root carbohydrate contents. The spear variables were yield, spear diameter, spear height, time for fern out, cellulose and lignin content. The plant were maintained by giving a fertilizer standard, irrigation and pest and diseases controls. Different altitudes significantly affected all plant growth variables. Plant height, number of shoot, root, bud and plant fresh weight significantly higher at low altitude, whilst the carbohydrate content decreased. Three cultivars, Tainan 2, Jersey Jewel and NJ880 had a stable growth at three altitudes. In addition the interaction between altitude and cultivar was significant for number of shoot and bud. Spear yield and quality was significantly affected by altitudes. In high altitude the asparagus produced high yield, higher in spear diameter and height. However, all the quality criteria were below standard for export. Increasing altitude caused an increased in cellulose and lignin content. There were no significant di Ifcrcnt between cultivar for :111variable measured, except cellulose.. ... -. -Canonical correlahon analysls slYows thatthere\vasa Close relationship between environmental factors and early plant growth. The main environmental factor which influenced the plant growth were air temperature and relative humidity (rc=O.699)