Inbreeding Effects on the Performance and Genomic Prediction for Polysomic Tetraploid Potato Offspring Grown at High Nordic Latitudes

Abstract

Inbreeding depression (ID) is caused by increased homozygosity in the offspring after selfing. Although the self-compatible, highly heterozygous, tetrasomic polyploid potato (Solanum tuberosum L.) suffers from ID, some argue that the potential genetic gains from using inbred lines in a sexual propagation system of potato are too large to be ignored. The aim of this research was to assess the effects of inbreeding on potato offspring performance under a high latitude and the accuracy of the genomic prediction of breeding values (GEBVs) for further use in selection. Four inbred (S1) and two hybrid (F1) offspring and their parents (S0) were used in the experiment, with a field layout of an augmented design with the four S0 replicated in nine incomplete blocks comprising 100, four-plant plots at Umeå (63°49′30″ N 20°15′50″ E), Sweden. S0 was significantly (p < 0.01) better than both S1 and F1 offspring for tuber weight (total and according to five grading sizes), tuber shape and size uniformity, tuber eye depth and reducing sugars in the tuber flesh, while F1 was significantly (p < 0.01) better than S1 for all tuber weight and uniformity traits. Some F1 hybrid offspring (15–19%) had better total tuber yield than the best-performing parent. The GEBV accuracy ranged from −0.3928 to 0.4436. Overall, tuber shape uniformity had the highest GEBV accuracy, while tuber weight traits exhibited the lowest accuracy. The F1 full sib’s GEBV accuracy was higher, on average, than that of S1. Genomic prediction may facilitate eliminating undesired inbred or hybrid offspring for further use in the genetic betterment of potato.

Genomic Prediction for Inbred and Hybrid Polysomic Tetraploid Potato Offspring

“…The results across the testing sites and over the years (Table 2) confirm that inbreeding significantly affects tuber yield, as noted before in this and other potato cultigen pools [30]. This inbreeding depression relates to the accumulation of deleterious recessive alleles due to vegetative propagation in this polyploid tuber crop with tetrasomic inheritance [41].…”

“…We investigated the prediction ability of the model considering the same breeding populations as in Ortiz et al [30], i.e., four S 1 and their two related F 1 offspring. We extended the original prediction problems in Ortiz et al [30] to multi-environment settings, so we considered the following problems: (1) prediction of the response variable in one environment using the data registered in another environment; (2) prediction among full sibs; and (3) prediction of non-related individuals and half sibs.…”

“…This perspective opens up the possibility of fixing advantageous homozygous recombinants through inbreeding, thereby contributing to the enhanced performance of crops. In this regard, Ortiz et al [30] recently pointed out that GEBVs may lead to eliminating undesired inbred or hybrid offspring in potato breeding. Hence, the objectives of our research, from which this manuscript ensued, were to assess the value of genomic best linear unbiased predictors (GBLUPs) based on the reaction norm model [31] for early generation selection for tuber yield in the potato crop, as well as the effect of inbreeding on genomic prediction ability (r) for this characteristic, thus emphasizing its critical role in enhancing selection accuracy and efficiency.…”

Genomic prediction for polysomic tetraploid potato inbred and hybrid offspring

“…We investigated the prediction ability of model considering the same breeding populations as in Ortiz et al (2023b); i.e., four S 1 and their two related F 1 offspring. We extended the original prediction problems in Ortiz et al (2023b) to the multi-environment settings, so we considered the following problems: 1) prediction of the response variable in one environment using the data registered in another environment; 2) prediction among fullsibs and 3) prediction of non-related individuals and halfsibs.…”

Development of near homozygous lines for diploid hybrid TPS breeding in potatoes

“…The cultivated potatoes are self-compatible auto-tetraploids. However, selfing in heterozygous tetraploid potato clones results in significant inbreeding depression [ 1 ]. As a result, the homozygous lines could not be developed in tetraploid potatoes, and the varieties and advanced breeding material are only maintained as tubers.…”