Development of Sclerotinia Head Rot Resistant Germplasm Utilizing H. maximiliani and H. nuttallii
2007
Jan, C.C. | Feng, J. | Seiler, G.J. | Rashid, K.Y.
Interspecific hybridization of NMS HA 89 with Sclerotinia head rot resistant wild diploid perennial H. maximiliani and H. nuttallii accessions was successful using embryo rescue. A total of 162 F1 hybrid plants were obtained after rescuing 228 embryos from 70,500 pollinated florets. Most F1 plants had the expected 2n chromosome number of 34. A few F1 hybrids had a 2n=51 chromosome number which was assumed to have resulted from fertilization of normal gametes with unreduced gametes. Most F1 plants with the 2n=34 chromosome number had low pollen stainability of around 1%, and consequently low backcross seed set with only 85 seeds from 506 pollinated heads. Backcrosses of 2n=34 F1 plants with HA 441 produced BC1F1 progeny with 2n=34 or 35 chromosomes. Sib-pollination among heads with colchicine-induced chromosome doubling also had low seed set with 250 seeds from 425 pollinated heads producing amphiploids with 2n=62 to 68 chromosomes. Backcrossing of 2n=34 to 35 F1 plants with HA 441 is now in progress, as well as sib-pollination of the amphiploids for seed increase.
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