Chlorophyll Mutations Research Articles

Studies on mutagenic effectiveness and efficiency of gamma rays and its effect on quantitative traits in finger millet (Eleusine coracana L. Gaertn)

Dry seeds (12% moisture) of two finger millet cultivar viz., Dapoli-1 and Dapoli Safed were irradiated with four doses of gamma-rays viz., 400 Gy, 500 Gy, 600 Gy and 700 Gy at BARC, Mumbai. In laboratory test, root and shoot lengths of seedlings were decreased with increase in dose of gamma rays. Similarly, germination percentage and survival rate of seedlings were decreased with increase in dose of gamma irradiation during field study. In M1 generation, three types of chlorophyll mutations viz., albino, xantha and viridis were observed. Albino and xantha were observed in all treatments, whereas, viridis observed only in lower doses viz., 400 Gy and 500 Gy. Based on the chlorophyll mutation frequency on M1 plants, mutagenic effectiveness and efficiency were computed. In Dapoli-1 variety, two early maturing mutants and three high yielding mutants were isolated from 500 Gy dose and 600 Gy dose, respectively. In M2 generation, the mutagenic treatments were effective in inducing various types of chlorophyll and morphological macro mutants, few of those show significant change in flowering, maturity and plant height character and few of them have good breeding value.

Scandinavian mutation research in barley - a historical review.

In 1928, the Swedish geneticists Hermann Nilsson-Ehle and Åke Gustafsson started on their suggestion experiments with induced mutations using the barley crop. In 1953, at the instigation of the Swedish Government, the 'Group for Theoretical and Applied Mutation Research' was established. Its aim was to study basic research problems in order to influence and improve methods for breeding cultivated plants. The research was non-commercial, even if some mutants were of practical importance. The peaks of activities occurred during the 1950s, 1960s and 1970s. Applying X-rays and UV-irradiation very soon the first chlorophyll mutations were obtained followed by the first viable mutations 'Erectoides'. Soon the X-ray experiments expanded with other types of irradiation such as neutrons etc. and finally with chemical mutagens, starting with mustard gas and concluding with the sodium azide. The research brought a wealth of observations of general biological importance, high increased mutation frequencies, difference in the mutation spectrum and to direct mutagenesis for specific genes. A rather large collection of morphological and physiological mutations, about 12 000 different mutant alleles, with a very broad variation were collected and incorporated into the Nordic Genetic Resource Center (NordGen) Sweden. Barley, the main experimental crop has become one of the few higher plants in which biochemical genetics and molecular biological studies are now feasible. The collection is an outstanding material for mapping genes and investigating the barley genome. Several characters have been studied and analyzed in more detail and are presented in this historical review.

Frequency and spectrum of chlorophyll mutations in greengram [Vigna radiata (L.) Wilczek

Greengram [ Vigna radiata (L.) Wilczek], popularly known as mungbean, is third most important pulse crop of India. Mungbean is a cheap source of dietary protein for the poor, with high levels of folate and iron compared with many other legumes. Variability is low available in mungbean and hence, to replace conventional breeding, mutation breeding has gained its momentum. Induced mutagenesis thus seems to be an ideal methodology for the induction of desirable genetic variability. Chlorophyll mutations, an important index in the estimation of induced genetic changes in mutagen treated population are most widely employed for assessing the potentialities of mutagens in creating genetic variability. An investigation was carried out in two mungbean genotypes CO (Gg) 7 and NM 65 treated by two mutagens viz ., gamma rays and ethyl methane sulphonate. A wide range of chlorophyll mutations was observed and scored in M 2 generation. The highest frequency rate was noted at 300 Gray and 10 mM on M 1 plant basis and M 2 seedling basis in both the genotypes. The mutant chlorina and xantha occurred in all the treatments of gamma rays and EMS at higher proportions.

Mapping genes governing flower architecture and pollen development in a double mutant population of carrot.

A linkage map of carrot (Daucus carota L.) was developed in order to study reproductive traits. The F2 mapping population derived from an initial cross between a yellow leaf (yel) chlorophyll mutant and a compressed lamina (cola) mutant with unique flower defects of the sporophytic parts of male and female organs. The genetic map has a total length of 781 cM and included 285 loci. The length of the nine linkage groups (LGs) ranged between 65 and 145 cM. All LGs have been anchored to the reference map. The objective of this study was the generation of a well-saturated linkage map of D. carota. Mapping of the cola-locus associated with flower development and fertility was successfully demonstrated. Two MADS-box genes (DcMADS3, DcMADS5) with prominent roles in flowering and reproduction as well as three additional genes (DcAOX2a, DcAOX2b, DcCHS2) with further importance for male reproduction were assigned to different loci that did not co-segregate with the cola-locus.

Effect of EMS on Induced Morphological Mutants and Chromosomal Variation in Cowpea (<i>Vigna unguiculata</i> (L.) Walp)

Effect of EMS (ethyl methane sulphonate) on induced morphological mutants and chromosomal variation in cowpea was studied using five different doses of mutagen along with a control in randomized blocked design with three replications. The morphological mutants there are two types of viable and chlorophyll mutants. Viable mutant contains tall, dwarf, early maturity, late maturity, leaf mutants pod mutant and flower mutants. The frequency of chlorophyll mutant contains albino, xantha and viridis. This concentration can damage or modify important components of plant cells and have been reported to affect the morphology, anatomy, biochemistry and physiology of plants differentially depending on the concentration level. These effects include changes in the cellular structure and metabolism of the plants e.g., dilation of thylakoid membranes, alteration in photosynthesis, modulation of the antioxidative system and accumulation of phenolic compounds. The morphological and chromosomal variation was found to be mutagen sensitive in somatic cells of cowpea. It was found to increase with increasing the concentration of EMS in Cowpea plants. The chemical mutagen like ethyl methane sulphonate induces high frequency of chromosomal changes like anaphasic bridge; anaphasic laggard, anaphasic bridge and clumbing of chromosome were including control plants also observed.

Effect of EMS on Induced Morphological Mutants and Chromosomal Variation in Cowpea (<i>Vigna unguiculata</i> (L.) Walp)

Effect of EMS (ethyl methane sulphonate) on induced morphological mutants and chromosomal variation in cowpea was studied using five different doses of mutagen along with a control in randomized blocked design with three replications. The morphological mutants there are two types of viable and chlorophyll mutants. Viable mutant contains tall, dwarf, early maturity, late maturity, leaf mutants pod mutant and flower mutants. The frequency of chlorophyll mutant contains albino, xantha and viridis. This concentration can damage or modify important components of plant cells and have been reported to affect the morphology, anatomy, biochemistry and physiology of plants differentially depending on the concentration level. These effects include changes in the cellular structure and metabolism of the plants e.g., dilation of thylakoid membranes, alteration in photosynthesis, modulation of the antioxidative system and accumulation of phenolic compounds. The morphological and chromosomal variation was found to be mutagen sensitive in somatic cells of cowpea. It was found to increase with increasing the concentration of EMS in Cowpea plants. The chemical mutagen like ethyl methane sulphonate induces high frequency of chromosomal changes like anaphasic bridge; anaphasic laggard, anaphasic bridge and clumbing of chromosome were including control plants also observed.

Induced Mutagenesis in <i>Cicer arietinum</i>

The traditional varieties of chick pea have low potentiality and restricted variability with respect to economic characters. Broadening the genetic base for crop improvement can be quickly achieved through induced mutagenesis. The present study was undertaken in order to comparing the effectiveness and efficiency of mutagens on Cicer arietinum. In this regard, Co – 4 variety of chick pea was subjected to different dose/concentration of Gamma rays (20, 30, 40, 50 and 60 kR) and Ethyl Methane Sulphonate (10, 20, 30, 40 and 50 mM) for inducing mutation. Mutagenic effectiveness and efficiency was calculated based on biological damage in M1 and chlorophyll mutations in M2. The results indicated that, mutagenic effectiveness increased with the increase in dose/concentration of mutagen. Intermediate treatments in general were found more efficient in causing less biological damage and inducing maximum amount of mutations. It shows that the chemical mutagens are more effective and efficient than physical mutagen for inducing mutation in Chick pea

Induced Mutagenesis in <i>Cicer arietinum</i>

The traditional varieties of chick pea have low potentiality and restricted variability with respect to economic characters. Broadening the genetic base for crop improvement can be quickly achieved through induced mutagenesis. The present study was undertaken in order to comparing the effectiveness and efficiency of mutagens on Cicer arietinum. In this regard, Co – 4 variety of chick pea was subjected to different dose/concentration of Gamma rays (20, 30, 40, 50 and 60 kR) and Ethyl Methane Sulphonate (10, 20, 30, 40 and 50 mM) for inducing mutation. Mutagenic effectiveness and efficiency was calculated based on biological damage in M1 and chlorophyll mutations in M2. The results indicated that, mutagenic effectiveness increased with the increase in dose/concentration of mutagen. Intermediate treatments in general were found more efficient in causing less biological damage and inducing maximum amount of mutations. It shows that the chemical mutagens are more effective and efficient than physical mutagen for inducing mutation in Chick pea

Chloroplast ultrastructure in leaves of Cucumis sativus chlorophyll mutant

The developing and young leaves of <em>Cucumis sativus</em> chlorophyll mutants are yellow, when mature they become green and do not differ in their colour from those of control plants. The mesophyll of yellow leaves contains a diversiform plastid population with a varying degree of defectiveness, which is mainly manifested in the reduction or disorganization of the typical thylakoid system. DNA areas, ribosome-like particles and aggregates of electron-dense material are preserved in the stroma of mutated plastids. Starch grains are deficient. Apart from mutated plastids, chloroplasts with a normal structure, as in control plants, were also observed.The leaf greening process is accompanied by a reconstruction and rearrangement of the inner chloroplast lamellar system and an ability to accumulate starch. However, in the mutant chloroplasts as compared with control-plant ones, an irregular arrangement of grana and reduced number of inter-grana thylakoids can be seen. An osmiophilic substance stored in the stroma of mutated plastids and the vesicles formed from an internal plastid membrane take part in restoration of the membrane system.

Screening for low Raffinose family oligosaccharides and low Phytic acid lines in macro mutant Urdbean (Vigna mungoL. Hepper)

Oligosaccharides are important component of urdbean in terms of metabolizable energy for monogastric animals and human. Sucrose, raffinose, stachyose and verbasecose are the four main oligosaccharides present in urdbean. Out of the four, only sucrose is nutritionally useful. When raffinose stachyose and verbascose are fermented by microbes present in the gut, the results are flatulence and discomfort, which ultimately lead to poor weight gain. The objectives of this work were to establish to identify low raffinose family oligosaccharide (RFO) and Low phytic acid (LPA) in macro mutants of TNAUCo (Bg) 6. The seeds of TNAUCo (Bg) 6 were treated with gamma rays (200Gy and 250Gy) EMS (15mM and 20mM). The frequency and spectrum of macro mutants different dose/concentration, number of chlorophyll mutants and Macro mutants observed. Chlorophyll mutants and viable mutants calculated based on the biological damage. The spectrum of chlorophyll mutants (Chlorina, Xantha, Albino and Viridis) and viable mutants (Tall and erect, dwarf, spreading, compact and bushy, crinkled and leathery, small leaf, big and broad leaf, narrow leaf, sterile, non flowering, pod and seed mutants) were observed in both generation. The spectrum of chlorophyll mutants increased with the decreased in dose of mutagen and increased with lower concentration. Total of 22 and 102 macro mutants were isolated from gamma ray and EMS treatments. Compare to all treatment 15mM of EMS treatments were establish more efficient in causing less biological injure and inducing highest amount of mutations. The total of 124 macro mutant three Low Verbascose mutant M2-F58 (0.06 mg/g), M2-F117 (0.13 mg/g) of 15mM, M2-F27 of 20mM (0.13 mg/g) and one low Phytate mutant in M2 -F37 of 15mM EMS (0.02 mg/g) were selected.

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).

Genetic and ultrastructural studies on an orange coloured chlorophyll mutant of winter rye (Secale cereale L.)

The feature of the orange colour of young seedlings, which appeared in inbred generation S<sub>2</sub> of a short straw form of winter rye cultivated in Jeleniec is described. Genetic analysis revealed that this feature is determined by one recessive gene, marked with the symbol cl<sub>2</sub> (chlorophyll lethal), because the plants with a double dose of this gene (recessive homozygotes) die four weeks after germination. In contrast to typical chloroplasts in normal plants (green), mesophyll cells of mutants (of orange colour) contain plastids devoid of grana thylakoids. The lamellar system of these plastids is composed only of more or less parallel single thylakoids. Short thylakoids often demonstrate a "staircase" arrangement forming in this way long thylakoids. Moreover, such plastids are characterized by the presence of 1-4 clusters of osmophilic globules. Starch grains were lacking in plastids of mutated plants.

Induced mutagenesis in recombinants and their parents in soybean [Glycine max(L.) Merril L

Six soybean accessions viz., TNAU S 7, TNAU S 55, DS 9501, TS 82, Himso 1563 and CO 2 and their 15 F1 and five F2 populations were taken with the objective of studying their response to gamma radiation. Among the parents, TS 82 and Himso 1563 were highly sensitive while CO 2 was less sensitive to the mutagen. Analysis of variance showed significant differences among treatment combinations for all the traits except number of seeds per pod. High frequency of chlorophyll mutants viz., 4.0 per cent at 3.0 grey for TNAU S 7 and 4.5 per cent for Himso 1563 at 2.5 grey occurred. Morphologically variable viable mutants during early phase of the crop and aberrants with modified stem structure, plant structure, dwarf, gigas, stunted, leaf morphology, small leaves, flower colour, pod colour, sterile, partially sterile, four seeded, small seeded, bold seeded, seed coat colour and high yielding mutants during the later stages were observed. High heritability coupled with high genetic advance was noted for plant height (TNAU S 7 / TS 82 at control and at 2.5 grey, and DS 9501 / TS 82 at control), number of clusters per plant (TNAU S 7 / TS 82 at 2.5 grey), total number of pods per plant (DS 9501 / TS 82 at 2.5 grey, TNAU S 7 / TS 82 at control and at 2.5 grey) and total dry matter accumulation (DS 9501 / TS 82 at 3.0 grey). Directional selection in these populations may improve the yield attributes which will in turn increase the grain yield in soybean

Induced mutagenesis in cowpea [Vigna unguiculata(L.) Walp] var. Arka Garima

A study was undertaken in a cowpea [Vigna unguiculata (L.) Walp.] var. Arka Garima to assess the efficiency and effectiveness of physical as well as chemical mutagens and to induce viable mutation in qualitative traits which could be utilized directly or introduced into cowpea improvement programme. Germination percent decreased in general with increase in dose/concentration of mutagens. The inhibitory effect on these characters was more prominent with gamma rays than with EMS. The frequency of chlorophyll mutation increased with the increase in dose/concentration. Wide spectrum of chlorophyll mutations were obtained in the present study which includes albino, xantha, chlorina, viridis and xantha-viridis. The lower and intermediate doses of gamma rays (200 and 300 Gy) and EMS (0.25% and 0.30%) are recommended as most effective and efficient for exploring variability and isolating promising mutants. Significant morphological variability was created which include abnormalities in growth habit, leaf, flower, pod and seed coat. The frequency of morphological abnormalities increased with increase in dose of gamma rays until 300 Gy followed by a decline. However, in chemical mutagen treated population, a linear decline in frequency up to 0.35% was seen followed by increase in higher concentrations.

Study of chlorophyll and macromutations induced by gamma rays and sodium azide in urd bean (Vigna mungo L. Hepper).

The mutagenic effect of gamma rays (5, 10, 20, 30, 40, 50 and 60 kR) and sodium azide (1, 2, 3, 4, 5, 6 and 7 mM) alone or in combination (10 kR + 2 mM, 20 kR + 2 mM, 30 kR + 2 mM and 40 kR + 2 mM) on frequency and spectrum of chlorophyll and micromutations in cultivar, T9 of urd bean have been observed. The spectrum of chlorophyll mutations consisted of albina, chlorina, viresence, viridis and xentha. Out of these chlorophyll mutations, xantha type was predominant in both mutagenic treatments. Conclusively, the combination treatments have yielded the higher frequency, and various doses of mutagenic agents have independent response towards macromutations in bean cv-T9. These studies were broadly aimed at understanding the process of mutation, testing the efficacy of various mutagens, identifying optimum dose and best method of treatment; isolation of mutants of basic and applied value; elucidating the biological effects of gamma rays and sodium azide. Key words: Gamma rays, sodium azide (SA), chlorophyll, macro mutations, urd bean.

Haploid plants carrying a sodium azide-induced mutation (fdr1) produce fertile pollen grains due to first division restitution (FDR) in maize (Zea mays L.)

We induced a fdr1 mutation in maize which makes haploid plants malefertile due to first division restitution; the optimum sodium azide treatment on maize kernels has been identified. Sodium azide mutagenesis experiments were performed on haploid and diploid maize plants. Kernels with haploid embryos of maize inbred line B55 were induced by pollinating with RWS pollen. These kernels were treated with 0.2, 0.5, or 1.0mM sodium azide solution for 2h. The 0.5mM solution was optimal for inducing numerous albino sectors on the treated plants without significant damage. Kernels of a maize hybrid, Oh43×B55, were treated with sodium azide solutions at concentrations of 1.5, 2.0, 2.5, and 3.0mM. Haploids were generated by pollinating RWS pollen. The highest rate of chlorophyll mutations in seedlings (15.3% [13/85]) was recorded with the 2.5mM concentration. A mutated haploid plant (PP1-50) with higher pollen fertility was isolated during the experiments. This haploid plant produced four kernels on the ear after selfing. These kernels were germinated and produced ears with full seed set after selfing. The haploid plants induced from PP1-50 diploids also exhibited high pollen fertility. In situ hybridization studies showed that meiocytes in PP1-50 haploid anthers underwent first division restitution at a rate of 48% and produced equally divided dyads. We designated the genetic factor responsible for this high pollen fertility as fdr1. PP1-50 haploid ears exhibited high levels of sterility, as seen for regular haploids. Diploid PP1-50 meiocytes in the anther underwent normal meiosis, and all selfed progenies were normal diploids. We concluded that the fdr1 phenotype is only expressed in the anthers of haploid plants and not in the anthers of diploid plants.

Comparative mutagenic efficiency, effectiveness and induced polygenic variability in mothbean (Vigna acontifoliaL.)

Induced biological damage, polygenic variability and comparative mutagenic effectiveness and efficiency of EMS, MMS, SA and HA were studied in four varieties of moth bean, namely, RMO-40, RMO-257, Jwala and CZM-1. Gradual reduction in germination, pollen fertility and survival percentage was observed with increased doses of mutagens. The frequency of chlorophyll mutants was less and were of two types i.e., albino and xantha in which albino type was less frequent. The spectrum of morphological mutations was defined in ten different classes (revertant, bushy, bifurcated stem, bolted, sterile, miniature, branched, increased peduncle length, spreading habit, and increased primary branches). The most effective treatment appeared to be 0.05% MMS, whereas least were 50mM hydroxylamine.The effectiveness of various mutagen treatments was generally higher on RMO-40 and lower on CZM-1.The effectiveness of treatments was decreased in the order of MMS > SA> EMS > HA. The highest mutagenic efficiency was observed with 1.0 mM Sodium azide in the Mothbean variety RMO-40. On the basis of estimates of pooled over genotypes and doses with in a mutagen, SA was the most efficient mutagen followed by MMS, EMS and HA. In M3 generation, 15 progenies showed significantly superior seed yield per plant with higher magnitude of yield contributing traits then the best check, RMO-225. Branches per plant and pods per plant exhibited high genetic variability in M3 generation.

Developing Genetic Variability of Quinoa (<i>Chenopodium quinoa</i> Willd.) with Gamma Radiation for Use in Breeding Programs

Quinoa (Chenopodium quinoa Willd.) is a staple food produced mainly by small-scale subsistence farmers in Peru’s highland. Dry seeds (cv. Pasankalla) were irradiated with doses of 150 Gy, 250 Gy and 350 Gy. In the M1 generation, the germination process was delayed with increasing radiation dose; seedling height, root length and leaf development were most reduced at 250 Gy and at 350 Gy, no plants survived. In M2, the maximum spectrum of chlorophyll mutations corresponded to 150 Gy and the maximum frequency to 250 Gy. The chlorine mutation was predominant, followed by xantha. Changes were registered for branch number, pedicel length, plant height, life-cycle duration, stem and foliage colour, and leaf morphology at the two doses, with improvements in plant type. More than one mutation per plant was found, especially at 250 Gy. In M3, the same spectrum of mutations was observed, along with a valuable change in grain colour.

Efficiency and effectiveness of physical and chemical mutagens in Trigonella foenum graecum L

Trigonella foemum graecum L was utilized to study the Chlorophyll mutations, mutagenic efficiency and effectiveness by physical mutagen gamma rays and chemical mutagen EMS. The frequency of chlorophyll mutation in M1 & M2 generation were more in gamma treated plants but the mutation spectra and mutagenic efficiency of EMS was higher than gamma. The most efficient mutagens were 0. 02% EMS, 0.06% EMS and 3KR gamma radiation to induce mutation in T. foenum graceum L.

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.