Agronomic performance of diploid inbred potatoes and their F1 hybrid potatoes

Phenotypic uniformity and tuber yield are fundamental concerns in diploid inbred-based F1 hybrid breeding in potatoes. We evaluated the agronomic traits of 22 hybrid families grown in small and large pots and the field. These families were derived from crosses of heterozygous × heterozygous, homozygous × heterozygous, and homozygous × homozygous parents using highly homozygous plants of Solanum phureja, S. chacoense, and tenth selfed generation plants derived from an interspecific hybrid. Genetic variability was estimated using genome-wide single nucleotide polymorphism (SNP) markers. Hybrid populations from homozygous × homozygous parents exhibited the highest phenotypic and genetic uniformity levels. Hybrid vigor in hybrids of homozygous × homozygous parents was tremendously enormous for fecundity and growth (up to 2877.5% and 8153.6%, respectively) and moderately large for tuber yield (158.2 to 230.7%). SNP-based genome-wide percent heterozygosity ranged from 28.7 to 44.3% for heterozygous parents and 14.4 to 44.8% for hybrid populations. The heterozygosity was correlated most highly with tuber size (r = 0.691–0.684) and negatively with tuber number (r = − 0.518), resulting in a positive correlation with tuber yield (r = 0.498). Since the heterozygosity of 2x Atlantic was the second highest (44.3%), its hybrid population produced a high yield in the field (925.6 g/plant) close to the yield of tetraploid potatoes. Thus, yield potential can be predicted by the genome-wide percent heterozygosity, possibly because many genetic factors collectively contributing to yield are located across the potato genome, and their accumulated heterotic effects can be represented as the genome-wide percent heterozygosity.