USING APOMICTIC TETRAPLOIDS TO MAKE A SELF-INCOMPATIBLE DIPLOID PENSACOLA BAHIAGRASS CLONE SET SEED

The objective of this study was to transfer obligate apomixis from common bahiagrass, Paspalum notatum Flugge (CT) (2n = 40), to Pensacola bahiagrass Paspalum notatum var. saurae Parodi (PD) (2n = 20). A completely self-incompatible PD clone 17-29 crossed with six (2n = 40) hybrids (HT) derived from doubled PD x CT hybrids produced 3,808 seeds from which 1,374 plants were obtained. Four of these F1's were apomictic triploids (2n = 30) that carried the shorter more decumbent culms, wider leaves, and larger seeds of their HT parent. The other 1,370 plants resembled 17-29 and failed to exhibit HT traits. HT pollen grains containing only PD chromosomes could have produced the 1,370 plants. Three generations of intermating the fertile HT parents should have transferred genes controlling apomixis and other characteristics from CT to PD chromosomes. The absence of HT traits in the 1,370 F1's and absence of apomixis in six plant progenies of 80 F1 selections indicate that HT genes were not transferred to PD chromosomes in the 1,370 F1 plants if they were F1's. Therefore, it seems unlikely that the 1,370 plants were F1's. A more plausible explanation is that the 1,370 plants were a selfed progeny of 17-29 produced by the mentor effect. Foreign HT pollen that mutually mixed with pollen from 17-29 probably caused the completely self-incompatible 17-29 clone to produce seed.