A method for quantitative genetic analysis of early clonal generation seedlings of an asexual crop with special application to a breeding population of the potato (Solarium tuberosum L.)

Abstract

Traditionally, the selection and breeding of asexual crops starts with a population of many thousands of seedlings derived from many crosses. Heavy screening of clones in the first field trial, sometimes up to 90% of the population, is a routine practice. The extent of such early selection pressure is questioned since plants in the early clonal generations are usually managed in an unconventional cultivation system as compared to that used in the later clonal generation trials or in the commercial practice. A method of quantitative genetic analysis is presented for analyzing data of quantitative traits which are collected from two different clonal generations. It is proposed to measure the regression type of heritability between two clonal generations in standard deviation unit and the expected response to selection in the first clonal generation with a physical unit used in the second clonal generation. Subsequently, the method was applied to a breeding population of potato. The results indicated that selection for quantitative traits in the first clonal generation was in most cases less efficient than direct selection in the second clonal generation.