Studies On Induced Mutagenesis Through Ethyl Methane Sulfonate In Cucumber(Cucumis Sativus L.) Cultivar Chinese Long(Line 9930)

We attempted to create a new germplasm of cucumber cultivar Chinese long(9930) using different doses of ethyl methane sulfonate(EMS) to induce variability at college of Horticulture, Northwest A&F University P.R. China during 2013-2015. We tested EMS concentration(0, 0.5, 1.0, 1.5, 2, 3% v/v) with post-treatment(0.1 M Na2S2O3 and water), EMS concentration(0, 0.5, 1.0, 1.5% v/v) over different treatment times(8, 16, 24 h), and EMS concentration(0, 0.5, 1.0, 1.5% v/v) with different treatment temperatures(20 and 28°C). In all experiments with increasing EMS concentration, germination percent, index, and rate were decreased. After addition of stop solution(0.1 M Na2S2O3), post-treatment mutated seeds showed higher germination(84.44%) and rate(37.5%) than seeds treated with water(80 and 34.07%, respectively), while the germination index was high in seeds treated with water. At 20°C, the germination index(4.13) and rate(56.25%) were affected to a greater extent than at 28°C(7.68 and 91.31%, respectively). Treatment times of 16 and 24 h showed similar results for germination percent and rate, while the germination index was decreased over time. There were significant differences in seedling height, fresh true leaf weight, seedling weight, and plant survival with increasing EMS concentration and time. Higher variations in the form of dwarf seedlings were recorded after treatment with 1.5% EMS for 24 h. Based on germination and morphological data, an EMS concentration of 1.5% for 24 h at 20°C and post-treatment with stop solution(0.1 M Na2S2O3) efficiently caused mutagenesis.The EMS have a negative effect on the total germination, reduced the speed of seed germination and viability. The cucumber seed germination, speed and index were reduced in the mutagenized seeds. We have phenotypically observed the variation in plant height, chlorophyll, leaf and flowers.During the induce mutation experiment cucumber cultivar Chinese long(Line 9930) were exposed to different concentration of EMS(0, 1.0, 1.5, 2% v/v). The data were recorded on germination(%), mortality ratio(%) and survival of the plants during M1 generation. During the M2 generation data were recorded on germination(%), survival, infertility, not crossed plant and loss of families. The germination was decreased with increased EMS concentration in M1 and M2 generation. The plant mortality increased and survival decreased during M1 generation, while during M2 generation 2% EMS gave high germination than control. During M1 generation chlorophyll mutation, leaf shape, flowers, fruit colors and mutation in geotropism was observed. During M2 generation the infertility of the plants were increased with increased EMS concentration. In the M2 generation 12 families with total number of 32 plants were identified as mutants. Among the 12 families, 5 families(12 plants) were identified from 1% EMS treated seeds, while the remaining 7 families(20 plants) from 1.5% EMS treated seeds. The data were recorded on phenotypic growth parameters of the identified mutant plants i.e. number of leaves plant-1, number of internode plant-1, internode length(10th from base), number of female flowers plant-1, position of first female flower on internode, fruit weight, fruit length and fruit diameter and great variation were observed in the studied parameters of mutants plants with respect to wild type. Among the mutant plants higher number of leaves plant-1(48), internode length(12.5cm), number of internode(30), number of female flower(23) and lower position of first female flower(3rd node) were recorded in 15B9, 111A2, 122B3, 15B3, and 141 B mutants respectively than wild type. The mutants plants produced maximum fruit weight(471. 68g), fruit length(38cm) in 121 B mutant and higher fruit diameter(4.88cm) in 15B9 mutant. Among the mutant fruits 12 mutant were screened for uniform bottom, middle and nick, 10 for uniform bottom and middle but thin nick, 5 for swollen bottom, uniform middle and nick and 1 for swollen middle, thin bottom and nick fruit shape. Five mutant plants were recorded which have black/brown spine in 122 B family. The ratio black spine(mutant) with white spine(wild type) was 1:3.