| 129-BJ52-A and 154-B,which are haploids, are derived from twin-seeding basic populations of CYARo2. 9003 and 9004. SAR-3 and SAR-4, which are autotriploid and autotetraploid respectively, are derived from twin-seeding basic populations of 9003 and 9004. In earlier research, an important phenomenon was discovered, which was that some F2 populations of diploids Fl individuals from the cross of polyploid xdiploid were uniform. Whether haploid has the character or not is the target of this research. In this research, two aspects were explored for many lines from 129-8,152-A and 154-B: First, chromosome behavior during meiosis, especially chromosome segregation mode and the generating mechanism for n-gamete. Second, reproductive behavior of haploid and embryo development for cross of haploid xdiploid. The main results are as following:1, Study on photosynthesis of haploid and diploid showed that there was little difference in net photosynthetic rate between them, haploid metabolism is normal, and miniature apparatus seem not affect the metabolism. 2. The results of pollen stainability identified with the method of 1%I2-KI revealed that especial haploid pollen stainability was 4.12%, higher than normal haploid(1.23%), while lower than the normal diploid (95%).3. The haploid PMCs were observed and the results showed: (1)Because of the absence homologous pairing, haploid mostly formed univalents and only a little mutivalents at diakinesis, the average paring form wasl 1.12 I +0.25 II-KX09III+0.07IV. (2)During anaphase I in the haploid,varying numbers of chromosomes move to the two poles. Distributions of 6:6,4:8,3:9,5:7,0:12 and so on, which resulted in many sterile gametes. In short, haploid had irregular meiosis, so the sterility of haploid is relatively low.4. Observations to the embryo sac structure of haploid showed that: a few normal embryo sacs(5.20%)differentiate completely, which have egg apparatus, tow pole nucleus and antipodal cells, while the majority of them(94.8%) were abnormal, for example they have one-polar nuclei, multi-polar nuclei, no-egg apparatus and no- antipodal cells.5. Haploid inbreeding was sterility and seed-setting for the cross of haploid xdiploid was relatively low, but 20% diploid pollens can geminate on the pistile of haploid, penetrate into, and arrive at micropyle. The barriers of crosses may occurred during fertilization, including single-fertilization (2.33%), non-fertilization (93%), abnormal or prolonged development of proembryo and degeneration of endosperm. The reasons of it are as following: (1)female gamete was sterility,(2)male gamete was sterility. (3)The barriers of affinity between female gamete and male gamete. (4)The non-synchronic development of female gamete and male gamete.(5)single-fertilization.6. Seed-setting for the cross of especial haploid*diploid was higher than normal haploidxdiploid, The reasons of it are as following: (1)Unreduced 2N gametes of female and male formed.(2)The mother cells of macrospore and microspore directly go mitosis by-passed meiosis to form normally fertility gametes. (3) Apomixis.7. The identification for the character of progenies of haploidxdiploid revealed that:(1)Most of the progenies were diploids and only a few of them were aneuploids.(2)SSRs marker analysis showed that all the FI were true hybrids. Markers for either parent could be present in FI progenies.(3)Two F2 populations from FI strains were uniform: statistical analysis showed that compared with Shan You 63, there was no much difference in height, days to heading, productive tillers per plant, length of panicle. SSRs marker analysis showed that all bands were uniform among individuals of F2.
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