Spectrum Of Chlorophyll Mutations Research Articles

Spectrum of chlorophyll mutations and morphological variations in Abelmoschus esculentus L. induced through gamma radiation

Okra [Abelmoschus esculentus (L.) Moench], is an economically exploited important traditional vegetable crop of the world. The present investigation examined the variability in induced chlorophyll mutants and othermorphological variations in okra. Seeds of two open pollinated popular varieties of okra namely Arka Anamika and Arka Abhay were irradiated with gamma doses of 30, 50 and 80 kR. The treatment 50 kR enhanced plant height, number of fruits per plant, fruit length, single fruit weight and total fruit yield per plant. Spectrum of several chlorophyll mutants were observed in the M1 generation. Other macro-mutants such as early and late flowering types, dwarf statured plants, leaf and flower mutants were also noticed at different doses of gamma radiation. The total number of visible mutation followed a trend of increasing frequency with the increase in dose of radiation.

Mutagenic effectiveness and efficiency in barnyard millet (Echinochloa frumentacea) using physical, chemical and combination of mutagens

The present investigation was undertaken to study the frequency and spectrum of Chlorophyll mutations along with the mutagenic effectiveness and efficiency of different doses of EMS, Gamma ray and combination of both, in barnyard millet variety CO(Kv). 2. In M2 generation, no chlorophyll mutations were observed in the control population. The treatments behaved differently in the frequency of occurrence of chlorophyll mutations. The spectrum of chlorophyll mutations (chlorina, xantha, albino, viridis, and striata) were observed and grouped. Except striata, remaining four kinds of mutations viz., xantha, chlorina, viridis and albino were observed more frequently. The overall mutation spectrum showed that chlorina (0.47%) occurred with the highest frequency, followed by albino (0.37%), xantha (0.26%) viridis (0.19%) and Striata (0.08%). The mutagenic effectiveness decreased with the increase in dose of mutagen in both mutagens, indicating that negative relationship between effectiveness and dose of mutagen. Mutagenic efficiency (mutation rate in relation to M1 damage) in both mutagens was highest at the lowest dose and it decreased with the increase in dose. The study concluded that Barnyard millet, Co(Kv).2 millet responds well to EMS, Gamma ray and combination of EMS and Gamma ray treatments.

Induced genetic variability with EMS and studies on frequency and spectrum of chlorophyll mutations in Pigeonpea

Four hundred seeds in each of two long duration pigeonpea (Cajanus cajan (L.) Millsp.) Cultures viz.,MAL 13 and MA156were treated with three different concentrations (0.01M, 0.015M and 0.02M) of EMS. At lab condition, germination varied from 71% in MAL 13 (at 0.02M) to 88% in MA 156 (at 0.01M). Average root and shoot length decreased with increase in dose concentration in both the genotypes. In M2, the highest in frequency of chlorophyll mutants (3.31%) at 0.015 M in MAL 13, followed by 2.73% at 0.015M in MA 156 and lowest (0.72%) was found at 0.01M in MA 156. Chlorophyll mutants viz., Albino, Xantha, Chlorina and Viridis were observed. MAL 13 is very sensitive to EMS and high efficiency was observed in 0.015M concentration.

Effect of chemical and physical mutagen in m1 generation and chlorophyll mutations in soybean (glycine max l. Merrill.)

Soybean variety ‘MACS 450’ was subjected to combination treatments of gamma rays (50 Gy and 100 Gy) and EMS (0.2% and 0.4%), different presoaked hours (12hrs, 16hrs and 20hrs) with 0.8% EMS, and gamma rays (50 Gy) with sodium azide (0.003 % and 0.005%) with an objective to induce variability for quantitative traits and estimate frequency and spectrum of chlorophyll mutations. In M 1 generation effect of mutagenic treatments was assessed on the basis of parameters survival (%), plant height reduction and seed sterility against control. Overall compare to all combination treatments 100Gy +0.4% EMS exerted more injurious effects in M 1 in the form of reduction in height (36.4%) and pod /plant (35.3). Among combination treatments of gamma rays + EMS and EMS treatment to presoaked seeds, the highest frequency of chlorophyll mutations (2.91% and 4.50%) was observed in 100 Gy + 0.4 % EMS and 16hrs PSW + 0.8% EMS respectively on M 2 plant basis. The results indicated that both these treatments are most effective to induce a wide range of genetic variability in soybean.

Effectiveness and Efficiency of Physical and Chemical Mutagens Inducing Chlorophyll Mutants in Two Rice Genotypes

Physical and chemical mutagens have been used to raise the genetic variation in most of the crop plants. An experiment was conducted to study the effect of gamma rays and Ethyl Methyl Sulfonate (EMS) in two quality rice genotypes of improved White Ponni and BPT 5204. In this study frequency and spectrum of chlorophyll mutations, mutagenic effectiveness and efficiency and mutation rate were estimated. The result from the study indicated that, albino was the predominant chlorophyll mutants that occur in M 2 generations of improved White Ponni and BPT 5204 at lower doses. The mutagenic effectiveness and efficiency were found to be higher at 100Gy of gamma radiation in both the varieties. The mutation rate of gamma rays (0.7131) was recorded high in improved White Ponni whereas, mutation rate of EMS (0.6693) was found to be higher in BPT 5204. In terms of efficiency, the mutation rate of gamma rays was registered to be higher based on injury (6.6587) and sterility (13.8777).

Studies on Frequency of Chlorophyll and Morphological Mutants in Chickpea

The effect of potent mutagenic chemicals, ethylmethane sulphonate (EMS), sodium azide (SA) and hydrazine hydrate (HZ), on two varieties, namely Avrodhi and BG- 256 of chickpea has been described in relation to chlorophyll and morphological mutations induced in the M2 generation. The frequency of mutations in terms of total plant basis was found to be higher at a lower concentration and concomitantly decreased with the increasing concentrations of EMS, whereas in SA and HZ it does not show any definite trend. Spectrum of chlorophyll mutations included xantha type followed by chlorina type, which outnumbered other types, namely albino, tigrina, and viridis in both the varieties, whereas the morphological mutants include changes for plant height, growth habit, foliage, pod and seed size, flowers, flowering, and maturity period. Frequency of mutations on variety basis indicated that both varieties were found to respond to the mutagenic treatments differently and on mutagen basis show relative specificity. The mutagenized population provides invaluable material for selecting types with the ideal combination of desirable features.

Studies on induction of chlorophyll mutations in soybean, Glycine max (L.) Merrill

The phenotypic response of two soybean cultivars to a chemical mutagen (ethyl methane sulphonate, EMS), physical mutagen (gamma rays) and their combinations were studied in M1 and M2 generations and the frequency and spectrum of chlorophyll mutations were worked out. Combined treatment was found to be more effective in inducing chlorophyll mutations compared to individual treatments of gamma rays and EMS in both the cultivars. As far as the spectrum of chlorophyll mutations is concerned, a wider spectrum in both the cultivars was observed in 45 kR + 0.2% EMS combined treatment.

Azide induced chlorophyll mutants in grain Sorghum varieties

Mutagenic action of sodium azide was investigated on two grain Sorghum varieties BD 569 and IS 2339. 16 h presoaking and 0.001 molar concentration were found to be most effective in inducing chlorophyll mutation spectrum at pH 3. Maximum frequency of M1 segregating panicles and M2 chlorophyll deficient seedlings were observed in IS 2339. Varietal differences are evident in their response to the mutagenic action of the chemical.

Modification of the mutagenic activity of propane sultone by some phenolic antioxidants

The effects of three phenolic antioxidants, butylated hydroxyanisole, butylated hydroxy toluene and propyl gallate on the mutagenic activity of propane sultone were studied using barley as the test system. The antioxidants produced seedling injury marginally but did not produce any chromosomal aberrations. When administered either prior to propane sultone treatment or in a mixture with it, the seedling injury, chromosomal aberrations, mutations per 100 M 1 spikes as well as M 2 chlorophyll mutation frequency, were enhanced. On the other hand, however, posttreatments reduced M 1 spike sterility, mutations per 100 M 1 spikes and M 2 chlorophyll mutation frequency. The spectrum of chlorophyll mutations was also broadened in the presence of these antioxidants.

Studies of induced chlorophyll mutations in Lathyrus sativus L.

Dry and dormant seeds (10% moisture) of Lathyrus sativus L. var. P10, P24, P288, P293, P585 and LC76 were irradiated with 10, 20, 30, 40 and 50 kR gamma rays. Both control and irradiated seeds of variety P288 was treated with 0.2 MES for six hours. Albino, Xantha, Albo-Xantha, Xanthalba, Albo-viridis, Virescence, Chlorina, Albescence, Tigrina and Maculata were the general types of chlorohyll mutations observed in all the six varieties at M2 generations.The spectrum of chlorophyll mutations was found to be dependent on the nature of genotypes. This was further noted to have linear relationship with doses. Maximum chlorohyll mutations were observed in LC76 which was proved to be more sensitive than rest of other varieties.High frequency of mutations was recorded in P288 as a result of differential and combined treatment of 0.2% MES which was seen to be as effective as 20 kR gamma rays.

Efficiency and Effectiveness of Gamma Rays and EMS in Rice

All varieties under study showed varied degrees of sensitivity for different characters, namely, survival, meiotic aberrations and pollen and spikeley sterility to gamma irradiation and less sensitive to EMS treatment. In gamma treatment the wild species O. spontinae exhibited the highest resistance for M1 injury, whereas the japonica (Norin-27) recorded the lowest and the rest are recorded intermediary values. There were no marked differences in frequency of chlorophyll mutations in gamma and EMS treated population. Within gamma treatment, frequency and spectrum of chlorophyll mutations, it was almost same in high and low fertility groups. However, EMS treated population recorded remarkable differences in frequency and spectrum of chlorophyll mutations in both the fertility groups. In general EMS was found to be most efficient and effective mutagen at high fertility level than gamma treatment.

Frequency and spectrum of chlorophyll-deficient mutations in rice after treatment with radiation and alkylating agents

Three varieties of rice were treated with gamma rays and two alkylating agents EMS and DES, alone and in combinations, with a view to finding out the frequency and spectrum of chlorophyll mutations in relation to the genotype and the nature of the mutagen. Chlorophyll mutation frequency was enhanced with increasing dose but dropped at very high doses (doses that induced over 90% seedling lethality in M 1). The fall was attributed to either the increased mutated sector and diplontic selection after exposure to very high doses or relatively high resistance of some of the seeds. Among chlorophyll mutants in M 2 induced by radiations as well as alkylating agents, the albina type formed the majority class. EMS induced a significantly higher proportion of albinas than did gamma rays.

Chemical mutagenesis inSorghum

The effect of NG, DEB and single and recurrent treatments after NMU on sensitivity in M1 and chlorophyll mutation frequency and spectrum in M2 was studied in the variety Co. 18 ofSorghum subglabrascens. Among the three chemical mutagens DEB was the most effective in delaying the emergence of primary leaf, and reducing the percentage of germination, survival and growth of root, coleoptile and seedlings, whereas NG was the least effective. The effect of mutagens increased with increasing dose. Recurrent treatments with NMU showed more drastic effects with respect to the above criteria than single treatments. The frequency of chimeras for chlorophyll deficiency in the M1 was found to be the maximum in the single treatments as compared to recurrent treatments after NMU. An increase in the reduction of pollen and seed fertility with an increase in dose of NMU and NG was observed. But the treatments with NMU showed more drastic effects on fertility than treatments with NG. The frequency of chlorophyll mutations was found to increase with dose in NMU, whereas such relationship was not observed in teratments with NG. The mutation rate was found to be higher in treatment with NMU than with NG. Whilealbina andxantha only were noticed in treatments with NG, a very wide spectrum of chlorophyll mutations was observed in NMU treatments. Recurrent treatments with NMU induced higher frequency and wider spectrum of chlorophyll mutations than single treatments.

The influence of post-treatment storage on the frequency of ethyleneimine-induced chromosomal aberrations and gene mutations in barley.

Dry seeds of spring barley variety MOS-121 were treated with ethyleneimine and after the treatment were stored in the desiccator over granulated KOH from 6 to 46 days. During this period statistically significant changes in the general level of chromosome rearrangements, number of chlorophyll mutations, death-rate and fertility of M 1-plants were observed. The spectrum of chlorophyll mutations also changed. The maximum genetic effect resulting from storage was noted by the 18th day, and this was followed by the decrease of injuries reached zero by the 46th day. The mode of changes in dynamics of the formation of chromosome aberrations, chlorophyll mutations and recessive lethal mutations proves the similar nature of the initial mechanisms of their potential changes.

A comparison of mutation induction in diploid and tetraploid rice

A comparative assessment of the frequency and spectrum of chlorophyll mutations in the M 2 and M 3 of three diploids and one tetraploid of rice after X-irradiation was made. As well as a linear relationship of the frequency of mutations with the dose of mutagen, a saturation effect was also evident. Among the three diploids, the maximum frequency of mutations was observed in T. N. 1, followed by G. E. B. 24 and A. S. D. 8. The diploid of G. E. B. 24 showed a higher frequency of mutations than the tetraploid when measured on the M1 plant basis only. The diploids showed a higher rate of mutations in the M 2 than in the M3.There was no relationship between the frequency of different types of chlorophyll mutations and the dose of X-rays. Albina, occurred in greater proportion than the other types of mutations in the diploids as well as in the tetraploid. The diploid showed a wider spectrum in the M 2, whereas the tetraploid recorded the maximum types of mutations in the M 3. Striking differences in the spectrum and the relative frequency of each type were observed among the three diploids and also between the diploid G. E. B. 24 and its tetraploid.The frequency and spectrum of induced mutations in the diploid and autotetraploid provided an insight into the genetic behaviour of the diploid and autotetraploid of G. E. B. 24, indicating that the genetics of diploidisation of the existing diploid rice may give evidence on the nature of the evolutionary pathway.

The effect of N-nitroso-N-methylurea, buthylmethane sulphonate and X-rays on the germination and production of chlorophyll mutations in einkorn wheat

Grains ofTriticum monococcum L. var.sofianum Körn. were treated with 0·1mm, 0·2mm and 0·3mm solutions of N-nitroso-N-methylurea (MNH), with 0·03m solution of buthylmethane sulphonate (BMS) and with X-rays in doses of 5 000r and 10 000r. The germination and development of individual colors of chlorophyl mutants were observed by the system developed byLamprecht (1960). All the mutants induced were classified according to their color changes into three main categories-homogenous unicolor, homogenous multicolor and heterogenous multicolor. In the last type the colors of individual leaves of the same plant varied. Anthocyanin mutations “albina” and “albino-transvirgata” sometimes coincided with the chlorophyll mutations. Some chlorophyll mutations showing complicated groups of colors appeared which were beyond the scale of classification by ordinary systems. The largest proportion in the spectrum of chlorophyll mutations, induced by MNH and X-rays was occupied by mutations of thealbina type. The broadest mutation spectrum in our experiments was induced by the application of 0·3mm MNH. The doses of X-rays used induced relatively higher numbers ofalbina-type chlorophyll mutations than MNH and BMS. In our experiments we succeeded in inducing on medium size samples ofTriticum monococcum L. var.sofianum Körn not only almost all types of chlorophyll mutations, induced byFujii (1960, 1962) andMatsumura (1960), but in addition also a great number of other even more complicated chlorophyll mutations, which have never been previously described inTriticum monococcum. L.

Modification of radiation damage with storage in seeds irradiated with thermal neutrons

Irradiation of seeds with thermal neutrons induces radioactivity in seeds. A study was undertaken to find out how the storage of the radioactive seeds, and consequent decay of activity, modify the radiation damage. Immediate hydration after thermal neutron irradiation of rice seeds showed higher mutation frequency than that obtained after storage of the seeds for 10 days. The spectrum of chlorophyll mutations was also different. Chromosome aberrations were scored in barley seeds in which immediate hydration increased the frequency of chromosome fragments. The study of γ-ray spectra and β-activity in irradiated rice and barley seeds showed detectable activation of Mg, P, K and Cu. Transmutation of elements and internal radioactivity are considered likely to contribute to the radiation damage. Even though the activity by itself is too small to cause direct damage, transmutation and internal activity may be able to modify the initial radiation damage in diverse ways. Restitution or repair of the lesions may have been affected leading to the enhanced effects noted in the present study.

Studies on modification of mutation response of barley seeds to ethyl methanesulfonate

1. Diploid six rowed barley seeds were soaked in water for 4, 8, 12, 16, 20, 24 and 28 hours, before treatment with 0.3% and 0.6% aqueous solution of ethyl methanesulfonate for 4 hours. Morphological, cytological and genetical changes induced were studied. 2. For all criteria studied, 16 hours or 20 hours presoaking in water was found to increase the sensitivity of the seeds to the maximum. Highest mutation rate was obtained at this time of presoaking, when appropriate concentration was used. 3. The proportion of chlorophyll to viable mutations was found to vary with various times of presoaking. At longer presoaking times, relatively higher proportion of viable mutations were obtained. This, however, was not associated with an increase in viable mutation rate. 4. The chlorophyll mutation spectrum was also found to vary for a given dose of EMS following different presoaking times. 5. The possible factors for the increased sensitivity at 16 to 20 hours soaking are discussed in light of similar studies with radiations as well as available microautoradiographic data pertaining to the sequence of chromosome duplication in germinating barley seeds. It is concluded that a metabolic factor like DNA duplication in the cell initials may be involved in bestowing this increased sensitivity during this presoaking period.

Mutation research in canary grass

1. Irradiations with X-rays and neutrons of normal dry seeds (humidity 12.0%) of canary grass showed, depending on the dosage, typical differences in their influence on germination and survival of seedlings. 2. With increasing dosage of X-rays an increased reduction of fertility in the M1-generation was observed. A much weaker influence was also observed in the M2-generation. 3. The percentage of chlorophyll mutations in the M2 distinctly increased with increasing X-ray dosage. The spectrum of chlorophyll mutations was analysed and discussed. 4. The occurrence of major morphological mutations in the seedling stage as well as in the adult stage was described and compared with the occurrence of chlorophyll mutations. The value of the chlorophyll test for establishing the presence of valuable minor modifying mutations in breeding material was discussed.