Breeding for cold chipping potato cultivars through sexual polyploidization and early generation selection.

摘要

Cold chipping (CC) potato cultivars could reduce storage loses, through their ability to process into light colored potato chips after cold (4 C) temperature storage. Breeding schemes using early generation selection (EGS) with 2x x 4x or 4x x 2x sexual polyploidization (SP) crosses to introgress CC and allelic variation from 2x potato species may accelerate development of improved cultivars. The research objectives were to determine (1) if variation for CC exists among potato species, accessions within species, and genotypes within accessions, (2) the response from EGS for light potato chip color, (3) the difference between SP and 4x x 4x crosses for introgressing CC from 2x potato species into 4x germplasm, and (4) the frequency of clones with cultivar potential from elite 4x x 4x crosses and SP. Evaluating CC consisted of making potato chips from genotypes after 3 and 6 months storage at 4 C. Chip color was rated 1 light–10 dark, colors ≤4 are industry acceptable and indicate a CC genotype. Selected 4x CC genotypes were field evaluated for A tuber yield (ATY), general tuber appearance (GTA), and specific gravity (SG).; Large amounts of variation for chip color was present among species, and among genotypes within accessions. Less variation was present among accessions within species. Cold chipping from 2x potato species is more efficiently introgressed using SP, rather than 4x x 4x. Increasing variation for chip color increased the frequency of CC genotypes. Positive genetic gains resulted from EGS of CC genotypes, however, genotype by environment interactions reduced responses. Therefore, testing over multiple production and storage environments will insure reliable cultivar performance. Breeding schemes that combine SP with EGS should rapidly develop CC germplasm.; More genotypes were selected with cultivar potential (favorable ATY, GTA, and SG) from elite 4x x 4x crosses than from SP, despite SP having increased variation for these traits. Poor yields in SP were found, and may be a consequence of the parent's genetic background. Diploid parents should be breed for favorable tuber characteristics, but done in a manor to create favorable interloci interactions needed for high yielding 4x progeny.