Sweet Potato New Variety Tainan No. 15
Wu-The Chen and Chin-Sheng Hsu
Sweet potato is am important upland crops in Tainan district. The cultivated area is approximately 90,000 hectares a year. This represents about 45% of the total cultivated area for sweet potato in Taiwan.
Sweep potato is mostly cultivated in fall in the Chia-nan rotational irrigated area, after the harvest of second rice crop (or second single rice crop). This Chia-nan area cultivation contributes about 80% of the total cultivated land for sweet potato in Tainan District.
The Agricultural Improvement Station in Tainan District (DAIS) has engaged in the study for the improvement of the crop ever since it was established. During the past years it had succeeded in developing such varieties as Tainan No.9 and Tainan No. 14. Unfortunately these varieties are not widely adapted to the Chia-nan irrigated area. The present local variety Hsin No. 31 has a lower percentage of chips and starch flour in fleshy root.
From 1965, with the financial support from J.C.R.R. (Joint Commission on Rural Reconstruction), the sweet potato breeding program is intensified. Its main objectives are to develop varieties which have wider adaptability for the fall cropping in Chia-nan irrigated area and a higher percentage of chips and starch flour in fleshy root.
Recently, Tainan DAIS has developed the Tainan No. 15, registered in 1973. According to experimental results it has the following agronomic characteristics.
1.The parent of Tainan No.15 are C472 crossed with local variety Hsin No.31 in 1965, elected in 1966, then passed the various yield trial regional and local test from 1969 to 1972.
2.It is a runner, has long vines and green color. The leaf blades are in hear-figure. The back surface of leaf blade is red-purple. The skin of fleshy root is red-purple and the flesh is yellowish. The fleshy root is spindle figure, smaller than that of check variety (Hsin No. 31) but the numbers of fleshy roots per plant are much more.
3.The average yield of Tainan No. 5 is 33,695 kg per hectare in the regional test (five locations in Chia-nan irrigated area). This is a 25.7% increase in yield. It has 32.7% in chips-making, 18.9% in starch-flour of fleshy root, an increase of 3% of chips and 2% of starch-flour the check variety.
4.From the cultural viewpoint, it is concluded that Tainan No. 15 can adapt to fall cropping (early October to early November) in Chia-nan irrigated area where the soils are light sand loam and loam. It has cold and draught-tolerance, early-maturity, and good tastes. It is not only good for feeding but also for table use.
The above results show that Tainan No.15 is well adapted to the Chia-nan irrigated area. Therefore it is expected to replace the local variety (Hsin No. 31) and to be distributed to the farmers.