SEGREGATION FOR MODE OF REPRODUCTION AND ITS RELATION TO HYBRID PERFORMANCE IN Paspalum simplex

ELSA A. BRUGNOLI; SILVANA C. FERRARI USANDIZAGA; ERIC J. MARTÍNEZ; CARLOS A. ACUÑA

Buenos Aires

Simposio; 5th International Symposium of Forage Breeding; 2015

Universidad de Buenos Aires

Breeding methods developed for apomictic species are based on the idea of fixing superior hybrids by apomixis. The progeny resulting from crosses between induced sexual genotypes and apomictic ecotypes is usually highly diverse in terms of agronomic traits and mode of reproduction. However, little is known about the effect of reproduction mode on agronomic traits. The objectives of the present work were to 1) generate a group of reproduction mode-segregating families by crossing sexual and apomictic Paspalum simplex genotypes, 2) identify apomictic hybrids, and 3) determine the relationship between mode of reproduction, and hybrid performance. Crosses were made between two induced sexual and 7 apomictic tetraploid ecotypes during February and March 2010. Seeds from each family were sown in trays with sterile soil in a greenhouse. About 30 plants were kept to establish a random sample from each combination. Identification of apomictic hybrids consisted on the PCR amplification of a specific molecular marker linked to apomixis in P. simplex. Then, hybrids were planted into the field on 1-m centers in a randomized complete block design with two replications. Plant diameter and height, initial regrowth, and seasonal regrowth, were evaluated. Comparisons between sexual and apomictic hybrids were made using ANOVA and the Tukey?s test. Eight cross combination were made, and a total of 232 hybrids were evaluated for mode of reproduction. The number of apomictic hybrids was variable among the analyzed families. The segregation ratio varied between 1:8.7 and 1:0.6 (apomictic: sexual) among families, and the average ratio was 1:2.4. We did not found differences between apomictic and sexual hybrids for all evaluated traits. Segregation for apomixis in P. simplex was highly variable and depended on the combination of parents used. The results indicate that apomixis does not affect forage performance in hybrids of P. simplex.