Comparative performance of FDR and SDR progenies from reciprocal 4x-2x crosses in potato

Abstract

Numerically unreduced (2n) gametes from first division restitution (FDR) are considered to be superior to 2n-gametes from second division restitution (SDR) because they transfer a larger proportion of the total parental heterozygosity and epistasis intact to the tetraploid progeny. This supposed superiority was investigated by comparing 12 sets of reciprocal 4x-2x crosses. Each diploid parent used in a reciprocal set produced 2n-pollen by FDR and 2n-eggs by SDR. Six agronomic characters were investigated. FDR progenies (from 4x.2x) were found to have higher mean yields due to more and bigger tubers. With respect to underwater weight, the overall progeny mean of FDR progenies was significantly higher than that of SDR progenies (from 2x.4x). However, the absolute difference found between both overall progeny means was too small to be of practical significance. No differences between FDR and SDR progeny means were found for vine maturity and chip colour. In addition to the progeny mean, within-progeny variation is important in potato breeding. For vine maturity a higher within-progeny variation was detected in SDR progenies, whereas within-progeny variations for yield, underwater weight and chip colour were not different in FDR and SDR progenies. With regard to vine maturity, we conclude that SDR 2n-gametes are superior to FDR 2n-gametes because, with the same progeny means of FDR and SDR progenies, the within-progeny variation was higher in SDR progenies. Therefore the assumed superiority of FDR 2n-gametes was confirmed for yield but was not observed for vine maturity, underwater weight and chip colour.

Use of 2n Gametes in Plant Breeding

“…In SDR, chromosome assortment is random (as in normal gametes) which results in a very heterogeneous population of gametes, but with a lower heterozygosity within one cell. For breeding purposes, 2n gametes of the FDR type are more advantageous than those obtained by SDR for transferring parental heterozygosity (Barcaccia et al, 2000;Barcaccia et al, 2003), although Hutten et al (1994) could not confirm this FDR superiority for all agronomic characteristics investigated in potato. By using molecular techniques as AFLP, random amplification of polymorphic DNA (RAPD) or isozyme analysis, the heterozygosity transmitted through 2n gametes can be calculated.…”

Genetic Structure of Diploid Gametes for the Production of Triploid Citrus Hybrids

“…In a previous work , the maternal heterozygosity restitution average produced by clementine SDR-2n gametes was 42.5%. The present results obtained for FDR-2n pollen gametes are in agreement with those obtained in potato (Peloquin, 1983;Hutten et al, 1994;Carputo et al, 2003) whereas for the SDR-2n pollen gametes, the average restitution is lower than those expected. Considering the low number of markers and SDR individuals analyzed, this average could be considered as normal for a SDR gamete population.…”

“…This is the first report of citrus tetraploid progenies recovered from unreduced pollen gametes in 4x x 2x sexual hybridizations. This phenomenon has been observed and studied in other species like Lilium (Lim et al, 2004), potato (Mendiburu and Peloquin, 1977b;Hutten et al, 1994;Carputo et al, 2003;Park et al, 2007) Boecheraspp. (Mau et al, 2013) and Arabidopsis (d'Erfurth et al, 2008).…”

“…They demonstrated that the biggest pollen grains were diploid resulting from FDR, although no progenies were recovered. In potato, genotypes that produce FDR-2npollen gametes and SDR-2n female gametes and genotypes that produce a mixture of SDR and FDR-2n female gametes have been described (Hutten et al, 1994). Such variability of mechanism of 2n gamete production has also been observed in other woody specie like Populus L. Liesebach et al (2015) observed that 2n male gametes were originated by both mechanisms in similar frequencies.…”

“…The average of PHR for SDR-2n gamete population was 30%. Assuming that a random distribution of heterozygous loci along the chromosomes occurred, global restitution of heterozygosity is expected to be near 80 % for FDR and 40 % for SDR (Peloquin, 1983;Hutten et al 1994;Carputo et al, 2003). In a previous work , the maternal heterozygosity restitution average produced by clementine SDR-2n gametes was 42.5%.…”