| The Iris×norrisii is a general term for the offspring group by crossing with I.dichotoma and I.domestica as parents,obtained by means of hybridization and backcrossing.It has the same advantages of cold-resistance,drought-tolerance and barren-resistance as its parents.In this study,the 125 I.×norrisii were used as materials,researching on their botanical traits,fruiting characteristics and germination rate.The main findings are as follows:The I.×norrisii began to grow scapes from late June to mid-July,in which the groups of(H×S)×S and(Y×S)×S were earlier than other genetic backgrounds.They flowered 7 to 10 days after growing scapes.The average flowering period was 46.57 days,and the difference between different plants varied from 21 days to 78 days.The average number of tillers of the I.×norrisii was 9.81,the average plant height was 119.10 cm,and the average number of small flowers was 6.86.The shape of the I.×norrisii seed was between the I.dichotoma and the I.domestica.Most of them were oval,dark black or dark brown,the surface was wrinkled and shiny,and they varied greatly in size.Among the measured 118 I.×norrisii seeds,the average weight of 1000 seeds was 20.58 g and the coefficient of variation was 40.91%.The average length of fruit was 25.55 mm,the coefficient of variation was 20.04%;the average width of fruit was8.24 mm,the coefficient of variation was 20.51%;the average length of seed was 4.82 mm,the coefficient of variation was 15.77%;the average width of seed was 3.13 mm,the coefficient of variation was 19.17%.The number of single fruit seeding differed greatly,ranging from 1.18 to 30.2.The average value was 7.31,and the coefficient of variation was 74.82%.It can be seen that the number of single fruit seeding varies greatly.The pollen germination method was used to determine the pollen viability.The pollen germination rate had a certain fluctuation,and it ranged from 7.52% to 41.21%.Determination of stigma receptivity with benzidine hydrogen peroxide,all plant stigmas measured were accessible.The natural seed setting rate of the I.×norrisii varied greatly from plant to plant,and the coefficient of variation was 75.15%.Among the 125 plants surveyed,the natural seed setting rate ranged from 0 to 61.32%,and 7 natural seed set rates were 0,accounting for 5.6% of the total;40 plants’ natural fruiting rate was less than 10%,accounting for 32% of the total;only3 plants had a seed setting rate of more than 50%,accounting for 2.4% of the total.We made the I.×norrisii self-crossing and hybridization by artificial pollination.According to the rate of seed setting,among the tested 31 plants,the number of seeds of the self-crossing single fruit of the I.×norrisii ranged from 0.69 to 19.78,with an average of 5.81,and the number of single fruit seeding of 27 plants was less than 10,among which there are even no seeds in individual fruits,accounting for 87.10% of the total.The hybrid seed settingrate of different plants of I.×norrisii varied greatly,ranging from 0 to 86.67%.Compared with the self-fertility rate,the hybrid seed setting rate was generally higher than the self-crossing rate.In the hybrid combination,46 and 99,28 and 99 were all reciprocal crossovers.According to 5 hybrid combinations with 99 as the male parent,it can be seen that when 99 is the male parent,the seed setting rate is significantly greater than 99 be the female parent.The seed viability was measured by TTC staining before the seed germination rate was measured.The results of the seed viability test showed that the 38 seeds tested had a good viability,except for 36 and 37,and the vitality of the remaining seeds were more than 90%.After sowing for 60 days in the greenhouse,the seed germination rate of different plants differed greatly,ranging from 1.47 to 79.30%,with an average of 38.83%.When the I.×norrisii seeds were cultured in a constant temperature incubator for 30 days,the seed germination rates of different plants varied greatly,ranging from 0 to 73.33%,with an average of 18.38%. |
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