Genetic architecture of plant height in winter rye introgression libraries

Abstract

With 4 figures and 1 table Abstract Plant height is an important trait for breeding and as fitness criterion in natural populations of rye (Secale cereale L.). Our objectives were to investigate the inheritance of plant height in rye introgression libraries and estimate the covariation between per se and testcross performance. Two introgression libraries containing each of 40 BC2S3 candidate introgression lines (pre-ILs) were tested at five locations in two years for per se and testcross performance. Donor population was the Iranian primitive rye accession Altevogt 14160. Plant height of the donor population was 145 ± 3.6 cm as population and 152 ± 2.9 and 132 ± 2.8 cm when crossed to the two testers, respectively. Pre-ILs were much closer to the recurrent parent, but still most of them exceeded the recurrent parent in per se performance. Estimates of the genotypic variance were significant (P = 0.01) for both per se and testcross performance. Entry-mean heritabilities were high in both libraries (0.97 and 0.94, respectively). Donor chromosome segments (DCS) of 59 of 72 pre-ILs had a significant (P = 0.05) effect on plant height compared to the recurrent parent. For the testcrosses, 10 pre-ILs still contributed DCS with significantly (P = 0.05) taller effects. Genotypic correlations between pre-ILs per se and as testcrosses were moderate for the two testers. In conclusion, plant height per se has a complex inheritance with many loci spread across the entire genome. Hybrid breeding, however, facilitates the use of genetic resources because the tallness is less pronounced in the testcrosses.