Enhanced seed set and crossover frequency in regenerated potato plants following anther and callus culture

Abstract

Twenty somaclones regenerated from a 2n pollen producing clone of diploid Solanum phureja and its anther-derived heterozygous diploid regenerant were found to vary for several morphological traits. However, after selection for fertility and diploidy, 4 of the 20 somaclones were not significantly different among themselves or from the original clone. When used as pollen parents in 4x–2x crosses to Solanum tuberosum cv. Atlantic, all the four somaclones exhibited higher seed set in comparison with the original clone. Progeny analysis revealed that 2 of the 4 exhibited higher recombination frequency between the centromere and the y gene. The estimated increased map distance of the y locus ranged from 3.4 to 10.0 units. Hybrid progeny analysis revealed no significant differences among 4x–2x and only a single difference among 2x–2x hybrid families for several morphological characters. Seed set and recombination data suggest that variation induced in tissue culture may have occurred without detectable morphological change. Assuming no adverse tissue culture effects, breakage of tight linkage between desirable and undesirable characters may be facilitated by shoot regeneration from callus before backcrossing.Key words: Solanum phureja, gene–centromere mapping, callus culture, recombination frequency, 4x–2x crosses.