The Hindu : Kerala News : Efforts on to identify disease-resistant sandal trees

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Thursday, Feb 03, 2005

Kerala

Kerala

Efforts on to identify disease-resistant sandal trees

By Our Staff Reporter

THRISSUR, FEB. 2. The scientists at the Kerala Forest Research Institute (KFRI), Peechi, in Thrissur district have taken up a project to identify sandal trees resistant to the dreaded spike disease.

The disease, which is a killer of sandal trees, is considered to be the biggest factor along with illegal felling for the drastic depletion of these trees in the country.

In the nine major sandal reserves of the Marayur range in Idukki, there were 1,86,594 recorded trees in 1979.

When a survey was conducted about six months back, the number had dwindled to less than 60,000.

The problem is also acute at the Sandal Reserve 51 in Marayur, considered one of the richest among the sandal reserves in the country in terms of the number of trees per hectare and oil content as well as in terms of genetic diversity of trees.

Here, the number of trees was 23,227 in 1979. But now the number is found to be only about 30.

"The disease has certainly played a critical role in the depletion. And many might have been illegally felled when they were found to be suffering from the disease," according to M. Balasundaram, who is heading the KFRI team engaged in the study.

Trial plots

Dr. Balasundaram told The Hindu here that the team had been trying to identify the disease-resistant variety of sandal by setting up progeny trial plots for seedlings from eight sandal provenances of the country.

One of the trial plots was at Marayur and the other at Veluppadam in Chalakkudy Forest division. The provenances selected for the study were Marayur, Bangalore, Mandagadde (Shimoga), Thangli (Chikkamangalur), Javadis and Chitteri in Tamil Nadu, Seoni in Madhya Pradesh and Koraput in Orissa.

The seedlings had already been planted in a plot at Marayur and were being observed in the last four years. Mr. Balasundaram said among the 900-odd seedlings planted at Marayur, about 500 were found to be surviving. Interestingly, the seedlings from Marayur were found to possess a high survival rate of 52 per cent. It was followed by the seedlings from Bangalore with a survival rate of 41 per cent. The Koraput seedlings had the lowest survival rate of 2.5 per cent.

At the Veluppadam plot, not a traditional sandal growing area, the survival rate varied from 1.6 per cent (Seoni seedlings) to 17.5 per cent (Marayur seedlings), he said.

He said the team was also screening the genetic traits of the sandal trees, which were found to be disease-evasive/resistant through DNA finger printing.

Replying to questions, Dr. Balasundaram, however, said so far no specific locus linked to spike disease resistance had been detected in the trees. The minor differences noticed in the genetic profiles of the disease-resistant and disease-affected varieties cannot be attributed to disease resistance, he clarified.

Restocking forest

He said breeding for disease resistance and restocking the forest with resistant varieties was an effective approach to minimise depletion of forest stock.

According to him, augmentation of sandal population through development of root suckers was possible only to a very limited scale. Seedlings were the better planting stock for afforestation.

He said people must also be encouraged to plant sandal trees and this could be done only if the law could be amended in a creative way by including provisions for preventing widespread destruction.

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