Production of haploids of potato (Solanum tuberosum subsp. tuberoslIm) and their identification with electrophoretic analysis

The frequency of haploid production following the inlerspecific pollination of eight tetraploid pot<lto cuhi var~ (Solanum wherosum subsp. IIlberosum) with Solanum phureja clone 1.22 was investigated. A total of 185 haploids were produced with an overall haploid frequency of 3.9 haploids/lOO [ruits. The haploid frequency was affected by the genotype of the maternal parent. Atlantic, NDR60-2, Superior, Saginaw Gold, Spartan Pearl, Nooksack and Onaway had frequencies of 6.2,5.1. 4.7, 3.9, 2.3 and 0,7 haploids/100 fruits, respectively. There were 60 and 57 haploids produced from Atlantic and Saginaw Gold, respectively, and no haploids were extracted from fruits of Lemhi Russet. Isozyme analysis and visual examination were performed independ­ ently to compare the efficienc\' of discriminfHing hybrids from haploids. Approximately 80% of tolal hybrids could be identified by electrophoretic analysis, while 77% were distinguished through visual examinalion. Pgm-2, which is unique in the done 1.22 and absent from all seed parents, was found to be the most useful locus in hybrid identification and 50% of total hybrids could be distinguished by Ihis allele. With similar rationale, Mdh-/ I allozyme, which was absent in six of the eight parents, identified 37% of lOlal hybrids, A comblOatic.':i. of both visual and ell:ctrophoretic methods made hybrid identi fication even more efficien t. with an average identification efficiency of 91 %. A scheme was proposed to develop a new haploid inducer which would be homozy:'.uus for both Pgm-2 and embryo spot.