High yielding senna for red soil tracts

By Our Agriculture Correspondent

A SUPERIOR senna (Cassia angustifolia) with high leaf and pod yields has been developed by the scientists at the department of Horticulture, Agriculture College and Research Institute (AC&RI), Killikulam, Thoothukudi, district. It has been released for commercial cultivation by the Tamil Nadu Agricultural University (TNAU) early this year.

Released as ``Senna KKM-1'', this high yielding variety is a selection from Tenkalam local. It has 38.5 per cent higher leaf yield, and 69.88 per cent higher pod yield than the local varieties, according to the scientists who developed this promising variety. Highly suited for the red soil belts of Tirunelveli and Thoothukudi districts, this variety does well as a rainfed crop.

It is a spreading bushy plant with seven to eight branches, which grow to a height of 80 to 100 cm. The plant has good rejuvenation capacity and is suitable for stripping at an interval of 30 days. It has a duration of 135 to 140 days. It has recorded an average leaf yield of 918 kg per hectare, and 352 kg pods per hectare. The total sennoside content of the plant is 2.54 per cent. The plant is used in the preparation of laxatives, and its dried leaves and pods have good export market, according to the scientists.

The new variety is free from all major pests and diseases. It will be ready for the first harvest of leaves in 60 days after sowing, and the second harvest can be had on the 90 th day.

The third and final harvesting of leaves can be had on 130 th day after sowing.

The pods are generally harvested along with the final harvest of the leaves. In the field trials, it had performed extremely well in all the locations.

It has been found ideally suitable for December and June-July sowing as rainfed crop, and January-February sowing as an irrigated crop.

About 27 kg seeds will be required for a rainfed crop to cover a hectare, and for the irrigated crop a seed rate of 20 kg would be sufficient to cover the same extent.

The new variety responds well to nutrient management. A dose of 50 kg nitrogen, 25 kg phosphorus and 40 kg potash is recommended as basal dressing, and two equal doses of 25 kg nitrogen should be applied as top dressing on the 40 th and 80 th day after sowing.

As rainfed crop, senna sowing should be taken up during the second half of December with receding monsoon. If sown with early monsoon, the newly sprouted seeds would not tolerate water inundation, and might rot.

The variety has been found to be extremely resistant to drought conditions. For taking up senna cultivation, the land should be well tilled, and liberal quantities of farmyard manure should be applied as basal dressing prior to the final ploughing.

The seeds should be soaked overnight in water to facilitate easy and uniform germination.

The seeds are then broadcast in the field in rainfed conditions. The irrigated crop is sown in line 45 cm apart leaving a space of 30 between plants in a row.

The field should be weeded twice to create a suitable condition for the crop to grow luxuriantly.

Senna is cultivated in the red soil tract of Tirunelveli and Thoothukudi districts as a rainfed crop. Only the local types are being cultivated so far, and they are poor yielders.

As such there was a long felt need for an improved variety with high yield among the farmers.

The release of this new variety will, therefore, be considered boon by the farmers as it will go a long way in improving their economy and export potential of the country, according to the scientists.

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