Rice Genetics IV - IRRI books - International Rice Research Institute

Table 7. Numbers of cDNAs showing various levels of differential expression in parents andhybrids of the Shanyou 63 cross.Zhenshan 97/ Zhenshan 97/ Minghui 63Group Relative Minghui 63 hybrid hybridsignal intensityFL a SD b C c FL a SD b C c FL a SD b C cLow ratio 0–0.2 12 28 6 18 48 8 17 28 50.2–0.5 13 52 1 20 92 5 29 34 60.5–0.67 11 62 4 31 71 9 60 64 8Subtotal 36 142 11 69 211 22 106 126 19About equal 0.67–1 70 94 21 116 76 24 147 143 861–1.5 134 50 27 102 28 11 83 55 17Subtotal 204 144 48 218 104 35 230 198 103High ratio 1.5–2 53 18 7 35 6 1 5 6 02–5 46 15 7 19 14 3 4 6 0>5 15 10 4 14 18 2 12 13 2Subtotal 114 43 18 68 38 6 21 25 2Total 354 329 77 355 353 63 357 349 124aFL = flag leaf. b SD = seedling. c C = in common between flag leaf and seedling.Table 8. Number of cDNAs with various levels of expression of heterosis in theShanyou 63 cross.Groups Heterosis (%) Flag leaf Seedlings CommonNegative heterosis < –100 18 14 2–100– –50 59 9 1Subtotal 77 23 3No heterosis –50– –15 9 21 8–15– +15 126 52 2415–50 85 90 20Subtotal 220 163 52Positive heterosis 50–100 39 79 19100–200 14 51 5>200 11 19 3Subtotal 64 149 27Total 361 335 82Forty-eight of the clones showing large expression differences in the Shanyou 63cross were selected to assay the expression in three hybrids and their parents, Zhenshan97/Minghui 63, Zhenshan 97/Teqing, and Guang B/Teqing, representing highly heterotic,intermediate, and nonheterotic crosses, respectively, as reported previously(Zhang et al 1995). Twenty-seven of the 48 clones showed a higher expression in theZhenshan 97/Minghui 63 hybrid than in the other two hybrids. Thirty-six of the 48clones showed a higher heterosis in expression in the Zhenshan 97/Minghui 63 hybridthan in the other two hybrids.We sequenced 35 of the clones and searched the sequences against the databases.Homology was found in the databases for 12 of the clones; 3 were homologous withchloroplast sequences and 9 were homologous with sequences with known functions.Genetic and molecular basis of heterosis in rice 183