Genus Iris has various species and widely distributed. And they have high ornamental value and economic value. In this study, the backcross hybrids of â… . dichotoma and â… . domestica were used as materials. The experiment mainly studied on characters of floral organ, stigma receptivity, meiotic process of PMC, pollen characters and fruit setting rates. And then study on the fertility in BC1 of â… , dichotoma and â… .domestica. The main results were as follows:The floral traits of BC1:stamen length, anther length, style length, style branch length, ovary length and ovary width were between parents and belonged to intermediate type. The variation coefficients of six flower traits were ranked from high to low as follow:style branch length>ovary length>ovary width>anther length>stamen length>style length. There was difference between stamen length and style length. The stamen length of 49 BC1 progeny were lower than style length. Among them, the difference of A-5-37 between stamen length and style length was the largest. The percentage is 83.05% and the maximum defference value was 5.76mm. The lower anther length is disadvantageous to naturally pollinate. This directly lead that natural fruit setting rates were low.The stigma receptivity of BC1 progeny did not have significant difference.2-4 hours after flowering, stigma gradually opened and began to secrete mucus, then stigma receptivity gradually increased. The surface of stigma was wetting and a large amount of mucus was secreted after 6-8 hours. The stigma receptivity was the highest and this was the best time for pollination.10 hours after flowering, stigma receptivity begin to weaken.12 hours after flowering, the stigmas were completely closed and had no receptivity.There were many chromosome abnormalities during meiosis in BC1 progeny. Diffuse diplotene appeared in meiosis â… . Metaphase â… appeared unpaired univalents and chromosome early separated; in anaphase â… , there were chromosome bridges and lagging chromosomes; telophase â… existed lagging bivalents; in metaphase â…¡, the unpaired chromosomes were found; anaphase â…¡ existed lagging bivalents; lagging chromosomes, chromosome unequally separated, chromosome bridges, chromosomes nonsynchronous division, abnormal tetrad and micronucleus were found in telophase â…¡.The chromosome types were observed in diakinesis of meiosis â… , bivalents accounted for the main part in F1 and BC1. But the part of bivalents was "C", "X", "O" and "V" type. And many isolated univalent also existed, which presented to rod or point. Trivalent and quadrivalents which were annular or "8" type. This also lead to produce abnormal and aborted pollens of BC1, which resulted in low fertility.When BC1 progeny were backcrossed with Iris dichotoma, the fruit setting rates of A-5-12, A-5-67, A-5-70 and A-5-85 were high. When BC1 progeny were backcrossed with Iris domestica, the fruit setting rates of A-5-67, A-5-70, A-5-83 and A-5-85 were high. When BC1 progeny were selfcrossed, there were difference in fruit setting rates. A-5-12 and A-5-83 were higher than 80%, and A-5-26 and A-5-68 were lower than 20%. It was worth noting that plants A-5-32, A-5-70, A-5-78 and A-5-85 did not produce pollen, the setting rates were well when crossed with â… . dichotoma or â… . domestica and showed fine affinity. The natural seed setting rates of no pollen BC1 progeny plants were low, even for 0.00%. This was the same rule with self fertility rates. This also indicated that the natural pollen was likely to come from the plant itself. The study provide a new theoretical basis to breed of Iris plants. |