Selection of Sweet Potato For Tolerance to Aluminum Toxicity: Screening Procedures and Field Test

Abstract

Abstract The effects of varying levels of Al on fibrous root growth variables of vine tip cuttings of sweet potato [Ipomoea batatas (L.) Lam] were tested in a quartz-sand medium in the greenhouse. A significant negative relationship between Al level and root growth was noted. Root weight was increased slightly on some clones at Al levels up to 250 μM. Aluminum levels > 500 μM considerably reduced root growth. Root lengths relative to the control were used in the screening of 379 sweet potato clones and in the preliminary identification of 60 tolerant and 55 sensitive clones. The tolerant clones had greater relative root length than the sensitive ones. In a field study, no significant differences in marketable root yield were noted between lime treatment (pH 5.4) and sulfur treatment (pH 4.2). The sulfur treatment, however, increased nonmarketable yield. The sensitive clones produced greater nonmarketable yield than the tolerant ones. A negative relationship between Al tolerance and yield in nonstress condition was indicated; tolerant clones generally yielded less than sensitive ones in nonstress field tests. Root lengths in the no-Al treatment in the greenhouse were significantly correlated with the marketable root yield and number in the limed field treatments.