Study On Polyploid Induction In Iris Dichotoma By Trifluralin And Pendimethalin

Iris dichotoma,which belongs to the genus Iris,Iridaceae family,is a perennial herb,widely distributed in China and it has strong ecological adaptability.However,I.dichotoma flowers are small,the plant is tall and easy to fall.To solve this problem,in this experiment,I.dichotoma was used as the test material,and two herbicides,trifluralin and pendimethalin were used to double induce I.dichotoma by soaking chromosome doubling and in vitro chromosome doubling.The effects of different herbicide concentrations and treatment times on I.dichotoma doubling were analyzed,and the germination rate,survival rate,mutation rate and doubling rate of the seeds of the treated I.dichotoma were compared and analyzed.The effects were statistically analyzed by morphological identification,stomatal characteristics identification and chromosome number identification of root tip cells.These have laid the foundation for the ploidy induction technology of I.dichotoma,and provided experimental materials for the breeding of new varieties of tetraploid I.dichotoma.The main research results are as follows:1.Both of the two herbicides,trifluralin and pendimethalin,had effects on I.dichotoma.Under the same method,pendimethalin had a stronger toxic effect on plants than trifluralin,and the induction effect of trifluralin was better than pendimethalin.Under the condition of using the same herbicide as the inducer,the effect of in vitro chromosome doubling was better than soaking doubling.2.The chromosome number of diploid I.dichotoma was 2n=2x=32,and that of tetraploid plants was 2n=4x=64.Morphological identification and stomatal characteristics identification could be used for preliminary identification of the mutant plants,and the root tip chromosome counting method could be used for final identification of the plants.3.In this experiment,trifluralin soaking doubling method,pendimethalin soaking doubling method and pendimethalin soaking doubling method was used to induce the seeds of I.dichotoma,and the differences among treatments were not obvious.Trifluralin was used to double the tissue culture to induce the seeds of I.dichotoma,and the optimal concentration was 50 mg/L,and the seeds were treated for 5 days.4.In this experiment,13 tetraploid plants were obtained by soaking doubling method of trifluralin.A total of 6 tetraploid plants were obtained by pendimethalin soaking doubling method.A total of 11 tetraploid plants were obtained by in vitro doubling with trifluralin.Six tetraploid plants were obtained by in vitro doubling method with pendimethalin.