| Rice institute of Sichuan Agricultural University obtained some early generation stable hybrid populations in F2 in rice by crossing triploid and tetraploid from twin-embryo seedling, diploid from early generation stable populations, triploid that is mutant strain in field with common diploid. The current research find cross between haploid and diploid can also product early generation stable hybrid populations in F3 for the first time. The following are the main results:1. Haploid as maternal parent was crossed with common diploid, and 68 seeds were gotten(the cross seed setting frequency were 0.12%-0.68%). 21 plants were obtained by tube culture. All of these F1 plants showed obvious heterosis, and were identical to their male parents morphologically. Statistical analysis revealed all of line groups in F2 progenies segregated madly. And two mutant plants were found in field ,one was sterile, another possessed hemi-glume.2. Whether the hybrids were true was analysed by SSR, and checked the chromosome number in the somatic cells of the hybrids by cytology technique. The results are as following: haploid and diploid were crossable, and the F1 hybrids plants were true. The cytology analysis revealed: there were haploidy cells, aneuploidy cells, diploidy cells in 15 F1 hybrids plants, but the percentages of the cells having different chromosome number were different in these hybrids plants respectively. In three of these hybrid plants the diploidy cells were many more than the haploidy cells, the aneuploidy cells didn't exist.3. In the field two crosses SARffl4/(Duohui No.3xCDR22) (IN) XZao2 (japonica, 2N) and SARIV-620 ( IN) XChunjiang683(indica, 2N) resulted inapparently uniform FS line groups 363 and 370 in Fa progenies, respectively. The statistical analysis indicated: there was no significant defference in plant heights, panicle length and productive panicle among the populations and the control variety Shanyou63. SSR analysis indicated all plants were homozygous at all primer loci at which the bands showed different length between the parentsof 363 and 370, and either some bands were identical to male parent, or some bands were identical to female parent at these loci.4. 4 pairs 1N-2N twin-seedling were analysed by SSR. At 48 primer loci, which located at the 11 chromosomes, polymorphism were showed between the genomes of diploid and haploid of Φ 152 (drived from SAR IV -620). Polymorphism also existed between the genomes of two seedlings of Φ 156. But no polymorphism produced between those of two seedlings of 0 129 and Φ 154. The genome of the other one 2N-2N two-seedling(also from SARIV-620) as CK was also assayed using the primer that produced polymorphic bands between two seedlings of Φ 154. Many loci showed polymorphism for the FI hybrids of Φ 152AXChunjiang683 and Φ 152BXChunjiang 683. No matter whether the genomes of twin seedlings show polymorphism the progenies will appear the phenomenon of stablility in early generation hybridize, we infer the factor(s) which control the phenomenon may exist at the genome of diploid of twin-seedling, or the phenomenon isn't involving the genome makeup of haploid (triploid or tetraploid), only homozygosity form in the course of cross of haploid (triploid or tetraploid) and diploid.
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