Selection and breeding of new sweet potato cultivar Sushu 29 with high starch content and multi-resistance

ObjectiveNew sweet potato variety with high starch content was selected and bred to provide variety sup-ports for the development of sweet potato starch industry in regions of the Yangtze River Basin.MethodHigh-quality va-riety Sushu 16 was used as male parent and Zhezishu 1 with high starch content and high resistance was the female parent. Through sexual hybridization,the new sweet potato cultivar was selected and bred by low generation selection of dry mat-ter content and field,and advanced generation identification of resistance and quality. And the new cultivar participated in the national sweet potato cultivar comparative test in Yangtze River Basin and tests in muti-sites of region.ResultSushu 29 bred in the study belonged to starch-type sweet potato cultivar. Its storage root was long fusiform with red skin and light-yellow flesh. The tuber formation was concentrated and in order. The average number of storage root per plant was 4.6 and the percentage of large and medium sweet potato was 84.8%. Besides,Sushu 29 had fine salt tolerance and stor-ability,and good quality after being cooked. The national sweet potato cultivar comparative test in Yangtze River Basin showed that the average dry yield was 9964.4 kg/ha,which increased by 11.95%compared with that of Xushu 22(CK). The average starch yield was 6786.3 kg/ha,which increased significantly by 15.58%compared with that of CK. The ave-rage dry matter content and starch rate of root were 33.75%and 23.00%respectively,with 3.40%and 2.95%(absolute va-lue)higher than that of CK. The cultivar was highly resistant to stem nematode,root rot and fusarium wilt,but was not resistant to black spot. In May 2016,this cultivar was identified by the National Sweet Potato Cultivar Identification Co-mmittee and was named as Sushu 29,with the identification number of 2016015.ConclusionThe new cultivar Sushu 29 has high yield stability and high starch yield. It is suitable for application and cultivation in the Yangtze River Basin and surrounding areas. In addition,this cultivar has a certain tolerance to salinity and alkalinity,and can be cultivated in the coastal saline-alkali land of Jiangsu.