Selection of superior accessions of turnip (Brassica rapa var. rapa L.) based on tuber quality‐related characters

Turnip (Brassica rapa var. rapa L.) (syn. B. campestris L. ssp. rapifera Sinsk) is an important crop species belonging to the Brassicaceae family. The 185 accessions belonging to this crop were collected from several areas of Toodshak region in Isfahan province, Iran, and their tubers were cultivated under homogeneous conditions in loamy clay soil. The morphological traits of different organs of those accessions were evaluated. Significant variations were detected among the accessions studied based on the traits recorded. Tuber shape showed high variation and included globose, oblong, ovate, obovate, and fusiform. Also, tuber skin color was highly variable, including white, bicolor white–violet, light violet, and dark violet. Tuber weight ranged from 1.56 to 35.70 g, while total soluble solids (TSS) of tuber flesh ranged from 7.00 to 11.80%. Principal component analysis (PCA) showed that 18 components were extracted by explaining 74.88% of total variance. The dendrogram obtained based on all the characters measured clustered the accessions into two major clusters. Sixteen accessions were placed into the first cluster, while the remaining accessions were placed into the second cluster which was divided into six subclusters. High level of morphological variabilities was observed among the accessions, which is applicable and useful for B. rapa var. rapa breeding programs. Based on the commercial and quality traits, 17 accessions could be selected for direct cultivation. Also, the promising accessions identified here can be utilized directly in breeding programs for genetic enhancement of this crop.