Tomato is an important vegetable known for the versatility of its uses both in fresh and processed food preparations. In the Philippines, it is considered as one of the major cash crops due to the great demand in the local market. However, production of tomato during off-season (rainy months from June to October) is hampered by many production constraints such as pest and diseases, unfavorable environmental factors, and lack of suitable varieties for planting. Thus, tomato produced during off-season commands a very high price.
In a study conducted by Dr. Lun G. Mateo and his group at the Central Luzon State University (CLSU), they found that grafting is an effective strategy to produce varieties of tomato that can withstand off-season production constraints. Two tomato hybrids, Apollo and CLN5915, were grafted to two different rootstocks, EG 203 (an eggplant) and H7996 (a tomato variety). Both rootstocks are known to be resistant to bacterial wilt, a highly devastating disease caused by Ralstonia solanacearum.
The researchers placed the grafted Apollo and CLN5915 seedlings in a compartment with a relative humidity (amount of water vapor in the air) approximately at 85-90% for a week. The newly grafted seedlings were then transferred into another chamber prior to transplanting. The planting beds were raised to 30 cm high and provided with rainshelter using 32-mesh plastic net. This was done to protect the seedlings from heavy rainfall and damage caused by waterlogged soil. Significant results from the two-year experiment revealed that the two grafted tomato seedlings showed higher percentage of survival compared to non-grafted plant. Grafted Apollo and H7996 had 97.2 and 77.8 survival percentage, respectively. On the other hand, non-grafted Apollo plant had zero percent survival. As to the ability to resist bacterial wilt, grafted varieties showed high percentage of survival (97.2%), while non-grafted plants had 70.8 survival percentage.
In terms of yield performance, grafted Apollo to EG 203 yielded an approximate of 13.1 tons/hectare, while Apollo seedlings grafted to H7996 yielded 11.7 tons/hectare, and the non-grafted plants yielded only 1.3 tons/hectare.
In an effort to integrate advances in grafting technology, a similar study was conducted by James R. Burleign at the Asian Vegetable Research and Development Center in Taiwan and Christian Ulrichs at the Technical University of Munich in Germany. The results of their studies can be very useful to determine the limitations and advantages of grafting technology when used under different environmental conditions.
For more information, please contact: Dr. Lun G. Mateo, Dennis R. Cacho, Anacleto F. Bala, Central Luzon State University, Muñoz, Nueva Ecija. Tel. No. (044)-456-0704)
By: Mary Charlotte O. Fresco, BAR Digest, April-June 2001 Issue (Vol. 3 No.2)