Breeding tetraploid Paspalum simplex: hybridization, early identification of apomicts, 2 and impact of apomixis on hybrid performance

MARTINEZ ERIC JAVIER; URBANI MARIO HUGO; MARTINEZ ERIC JAVIER; URBANI MARIO HUGO; FERRARI USANDIZAGA SILVANA C.; ACUÑA CARLOS ALBERTO; FERRARI USANDIZAGA SILVANA C.; ACUÑA CARLOS ALBERTO; BRUGNOLI ELSA ANDREA; ZILLI ALEX LEONEL; BRUGNOLI ELSA ANDREA; ZILLI ALEX LEONEL

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2019 vol. 59 p. 1617 - 1624

0011-183X

Apomictic grasses predominate among tropical forages, and specific breeding techniques 18 are needed for their genetic improvement. The objectives were to: 1- generate hybrids by 19 crossing tetraploid sexual and apomictic Paspalum simplex genotypes, 2- develop a 20 technique based on molecular markers for early identification of apomictic hybrids, and 3- 21 determine the relationship between mode of reproduction and performance of hybrids. 22 Crosses were made between two induced sexual and seven apomictic tetraploid plants. 23 Identification of apomictic hybrids during seedling stage was performed using a marker 24 linked to apomixis, and by flow cytometric seed analysis (FCSA). Hybrids were evaluated 25 under field conditions for plant diameter and height, initial regrowth, and seasonal regrowth 26 during two consecutive growing seasons. Sexual tetraploid plants used as female parents 27 behaved as allogamous since 95% of the progeny had male-specific markers. The ratio 28 between apomictic and sexual hybrids differed among crosses from 1:8.7 and 1:0.6 among 29 crosses, with a mean of 1:2.4. There was a 96% coincidence between the use of the 30 apomixis?linked marker and FCSA. A technique based on the use of an early DNA 31 isolation and the amplification of a molecular marker linked to apomixis was developed. 32 We found no overall difference between apomictic and sexual hybrids for the evaluated 33 traits, except for fall regrowth in the first year, for which apomictic hybrids were superior. 34 Generation of large tetraploid hybrid progenies is possible in P. simplex. Segregation for 35 mode of reproduction depends on parents involved. Agronomic performance is not related 36 to reproductive mode among tetraploid hybrids.