[Research on Breeding of Dioscorea opposita cv. Tiegun]

To breeding the new varieties Dioscorea opposita cv. Tiegun with the best comprehensive properties.

Seven new Dioscorea opposita. cv. Tiegun cultivars were screened by space mutation breeding of Dioscorea opposita cv. Tiegun bulbils. Yield,allantoin content,water soluble extractive and the resistance of these seven cultivars were compared with the main cultivar Dioscorea opposita cv. Tiegun( CK). Meanwhile, the nutrition quality of new cultivars No. 6 and No. 10 were compared with the main cultivar.

(1) The fresh weight per plant ranked in the order as follows: No. 6 > No. 10 > No. 4 > No. 9 > No. 1 > CK > No. 2 > No. 8. The drying rate ranked in the order as follows: No. 2 > No. 10 > No. 9 > No. 6 > No. 8 > CK > No. 1 > No. 4. Dry weight per plant ranked in the order as follows: No. 10 > No. 9 > No. 6 > No. 2 > No. 1 > CK > No. 4 > No. 8. The fresh weight per plant, drying rate and dry weight per plant of No. 6 and No. 10 were higher than the main cultivar. (2) The allantoin content ranked in the order as follows: No. 6 > No. 4 > No. 10 > CK > No. 9 > No. 8 > No. 2 > No. 1. (3) The water soluble extractive contents ranked in the order as follows: No. 6 > No. 2 > No. 4 > No. 10 > No. 1 > CK > No. 9 > No. 8. The water soluble extractive content of No. 6 was higher than No. 10 and the main cultivar. (4) No. 10 had the best taste of dry, soft, sweet and fragrant, No. 6 had the taste of dry, floury and hard, and No. 9 had the taste of dry and crisp. (5) No. 6 had the strongest resistance to Gloeosporium pestis and Cykindrosporium dioscoreae; No. 10 had a middle resistance to Gloeosporium pestis and a strong resistance to Cykindrosporium dioscoreae; and the main cultivar had a middle degree of being prone to Gloeosporium pestis and a middle resistance to Cykindrosporium dioscoreae. (6) The content of starch, reducing sugar, protein and ash in No. 6 and No. 10 were higher than that of the main cultivar,while the content of water in No. 6 and No. 10 were lower,which indicated that the nutrition quality of No. 6 and No. 10 is better than the main cultivar.

The new cultivar No. 10 is suitable for popularizing as a new variety of edible Dioscorea opposita cv. Tiegun. The new cultivar No. 6 is suitable for popularizing as a new variety of medicinal Dioscorea opposita cv. Tiegun.