Creation and validation of core subset of potato (Solanum tuberosum) germplasm

Potato (Solanum tuberosum L.) is the only non-cereal staple food crop globally. The progress of this temperate crop in the sub-tropical country relies strongly on improvement activities utilizing the genetic resources acquired over a time period. However, proper maintenance, evaluation and utilization of germplasm resources is a cumbersome task. Creation of core set of conserved genetic resources is an efficient and cost effective method of management of conserved germplasm and its use in breeding program. Indian collection of potato (Solanum tuberosum ssp tuberosum) constitutes 1399 accessions emanating from the five continents maintained under ex situ conservation. A core subset of 140 potato germplasm was developed using Power Core software based on 19 morphological traits. Majority of entries in the core subset were from South America (42.14%). Comparison of mean data using Newman-Keul's test and variances using Levene's test for different traits revealed representation of actual diversity of base population by the core subset. Correlations among the traits governed by co-adapted gene complexes were conserved in the core subset. Shannon-Weaver diversity indices indicate that the potato core subset maximized the phenotypic diversity of the potato germplasm. Validation of core subset using principal component analysis reveals that the first 4 PCs represents 55.27% of total variations in core subset compared to 52.50% that in entire collection. The identified core subset can be used in Indian potato improvement programs as well as in genomics studies.