Morphological and molecular characterization of multiplier onion (Allium cepa var. aggregatum) genotypes

Abstract

Abstract Multiplier onion (Allium cepa var. aggregatum), commonly known as shallot or potato onion, has been cultivated on a large scale in southern parts of India. It is mostly propagated by bulbs except few genotypes which produces seeds. It is famous for its use in the preparation of sambar which is an important South Indian dish. The multiplier onion produces 6–15 small bulbs in a cluster. Thus, its morphological and molecular characterization is an essential part for the genetic improvement. An experiment was laid out in the experimental field of ICAR-DOGR, Rajgurunagar, Pune during rabi 2019-20 and 2020-21 for screening of multiplier onion lines suitable for domestic as well as export purpose. The genotype 1534-Agg recorded highest total yield (287.17 q/ha). Molecular characterization of the multiplier onion was performed using recently produced polymorphic DNA-based molecular markers in onions (ILP-Intron Length Polymorphism markers). The genetic diversity of 36 genotypes of multiplier onion was examined using 17 ILP markers in this study. PIC values ​​ranged from 0.03 to 0.44 with a mean of 0.24, and amplification of ILP markers revealed a total of 41 loci, one of which was monomorphic. A total of 1008 bands were obtained. Principal component analysis (PCA) detected one PC contributing 54.54% of the genetic diversity of genotypes. A total of 17 primers were amplified and they produced 41 alleles in these genotypes. The genotypes 1539-Agg and 1523-Agg have the highest degree of similarity (0.97) in cluster A whereas, the least degree of similarity was revealed in cluster E between genotypes 1549-Agg and 1533-Agg. The genetic diversity among multiplier onion genotypes was estimated based on similarity coefficient of molecular markers facilitates the selection of diverse parents that can generate desirable segregants in future breeding program.