Is it possible to generate fast germinating and productive apomictic bahiagrass hybrids?

ZILLI, ALEX LEONEL; BRUGNOLI, ELSA ANDREA; MARCÓN, FLORENCIA; MARTÍNEZ, ERIC JAVIER; ACUÑA, CARLOS ALBERTO

Simposio; 5th Interntational Symposium of Forage Breeding; 2015

Eleven apomixis-segregating progenies were generated by crossing 9 apomictic and 3 sexual tetraploids genotypes, obtaining a total of 524 hybrids. Mode of reproduction was determined by a RAPD marker 100% linked to apospory in P. notatum, and the level of apospory expressivity was estimated by mature embryo sac observations. A total of 112 aposporic hybrids were planted into the field in a randomized complete block design with 4 clonal replicates. Two morphological and six agronomic traits were evaluated. Apospory expressivity showed a discontinuous variation with a range from 0 to 100%. Only 40% of the total aposporic hybrids or 5% of the total hybrids showed an apospory expressivity higher than 75%. A group of 18 hybrids was selected based on general vigor and expressivity of apospory. Germination was estimated in these 18 hybrids, 3 promising lines and 2 released cultivars (as checks) 21 days after sowing. This trait was highly variable, with values from 1% to 45.5% with an average of 16% (CV= 0.99 ). This low germination level could be due to seed dormancy, considering the short time between harvest and sowing. Only 5 aposporic hybrids out of the 18 had a germination level higher than 20%. Therefore, the efficiency of obtaining hybrids with good performance, high apospory expressivity and acceptable germination is less than 1% of the total generated hybrids. The low germination observed in these genotypes could be due to the fact that this trait was not considered in the selection of the progenitors. An extensive search of natural and artificial fast germinating plants should be performed considering its importance.