Characterization of chlorophyll deficient mutants in mungbean (Vigna radiata (L.) Wilczek)

A wide spectrum of chlorophyll mutants was obtained in M2 generation following mutagenesis with MMS, HZ and SA. All these chlorophyll deficient mutants were lethal except maculata, viridis and virescent. MMS treatments induced the highest frequency of chlorophyll mutations followed by HZ and SA. The frequency of chlorophyll mutations was dose dependent and increased with increasing concentrations of all the three mutagens utilized. Chlorina followed by xantha outnumbered the other types of chlorophyll mutants with all the three mutagens. Based on effectiveness, the order of mutagens was HZ > SA > MMS. Two criteria viz., pollen sterility (Mp/S) and seedling injury (Mp/I) were taken into consideration to determine the efficiency of the mutagens. With regard to these criteria, MMS mutagen was found to be the most efficient followed by HZ and SA. Lower concentrations of all the three mutagens were most effective and efficient in inducing chlorophyll mutations.

INDUCED GENETIC VARIABILITY IN SESAME (Sesamum indicum L): A COMPARATIVE STUDY ON THE MUTAGENIC EFFECTS OF RADIATION AND EMS IN SEED GERMINATION, POLLEN VIABILITY AND CHLOROPHYLL MUTANTS

The present study envisaged the effects of two mutagens, gamma rays and EMS on the phenotypes of two sesame varieties viz., TMV7 and SVPR1. A known quantity of dry, uniform, and healthy seeds of TMV7 and SVPR 1 were irradiated using Co60 (Cobalt 60) with different doses (250, 300, 350, 400, 450 Gy) of gamma rays. For chemical mutagenesis, different concentrations of EMS @ 0.20%, 0.40% and 0.60% was used and treated for 8 h. The dose-response curve of the probit analysis showed that the optimal lethal dose for SVPR1was lower than TMV7. The expected LD50 values of gamma radiation for TMV 7 and SVPR1 were 403.91Gy and 343.84Gy, respectively. For EMS, the expected LD50 values are 0.525 % and 0.276% for TMV7 and SVPR1 respectively. Germination and pollen fertility declined linearly with an increase in dose or concentration of the mutagens. Three classes of chlorophyll mutants viz., xantha, chlorine, and viridis in M2 generation reveals a dose dependent relationship between mutagens and frequency of chlorophyll mutants. Mutagenic effectiveness was higher at lower doses whereas mutagenic efficiency was observed higher at extremity doses in both the varieties. The overall considerations on M1 generation effects showed that SVPR1was highly sensitive to gamma rays and TMV7 produced more viable mutationsthan SVPR1. The current studies suggest gamma rays as an efficient mutagen to induce essential mutations in TMV7 for the further crop improvement program.

Mutagenic Effectiveness and Efficiency in [Vigna unguiculata (L.) Walp.] Variety Phule Phandari (PP) and VCM-8

Background: Mutation breeding is one of the cheapest and surest method of plant breeding. In mutation breeding program effectiveness and efficiency of mutagens could be helpful to realize the spectrum of desirable mutations in the treated populations. The effectiveness and efficiency of two mutagens EMS and gamma rays were studied in two varieties of cowpea [Vigna unguiculata (L.)Walp.]. Methods: In the present investigation, the seeds of two varieties of cowpea, phulepandhari and VCM-8 were treated with gamma rays and EMS to obtain the spectrum and frequency of chlorophyll mutations in M2 generation. Mutagenic effectiveness and efficiency were calculated using frequency of chlorophyll mutations.Result: The individual treatment of EMS was found to be more efficient than gamma rays to induce chlorophyll mutants. A progressive increase in mutation frequency of chlorophyll mutations was observed with increasing doses. Four different types of chlorophyll mutants, such as, chlorina albina, xantha and viridis were induced with effect of mutagens. The highest frequency of chlorophyll mutations was reported in the gamma rays. There was a dose dependent increase in the spectrum and frequency of chlorophyll mutations. The lower dosages of gamma rays and EMS were proved to be most effective and efficient. Among two mutagens used EMS was much more effective than gamma rays in both the varieties viz. variety phulepandhari and VCM-8.

Comparative Studies on Mutagenic Effectiveness and Efficiency in Horsegram [Macrotyloma uniflorum (Lam) Verdc.]

Background: Two horsegram varieties viz., PAIYUR 2 and CRIDA1-18R were mutated with gamma rays (G), electron beam (EB), G+EB and G+EMS (ethyl methane sulphonate) to determine the mutagenic potency in breeding programme.Methods: Uniform seeds treated with different mutagenic doses were raised in randomized block design which constituted M1 generation. Each plant was harvested individually and forwarded to M2 generation following plant to progeny row method.Result: A dose dependant decline was observed for seed germination, plant survival, root length, shoot length, plant height, pollen fertility and seed fertility in M1 population. Wide spectrum of chlorophyll mutants was induced in M2 generation with maximum frequency at EB followed by combination treatments (G+EMS and G+EB) in both varieties. The mutagenic effectiveness ranged from 0.14 per cent to 1.45 per cent in PAIYUR 2 and 0.15 per cent to 1.71 per cent in CRIDA1-18R. The high mutation rate for effectiveness was exhibited by G and G+EB. With reference to sterility, EB was found to be efficient mutagen in both varieties whereas varied efficiency was noted for lethality (EB - PAIYUR 2; G+EMS - CRIDA1-18R) and injury (G - PAIYUR 2; G+EMS - CRIDA1-18R).

Study on mutagenic effectiveness and efficiency of mutagens in inducing chlorophyll mutations in m2 generation in sorghum [Sorghum bicolor (L.) Moench ]

An investigation was carried out to create the variability generated through induced mutation in two sorghum populations viz., 296 B (Kharif) and Parbhani Moti (Rabi). Two mutagens viz., gamma irradiation (10 kR, 20kR, 30kR and 40kR) and EMS (0.1%EMS, 0.2%EMS, 0.3%EMS and 0.3%EMS) and their combination were used M2 generation. Mutagenic sensitivity in M2 generation on the basis of reduced germination and plant survival revealed a dose dependent reaction and differential response of the populations. In general, chlorophyll mutation frequency expressed on M2 seedling basis increased linearly with doses of three the mutagens in 296 B and Parbhani Moti. The frequency was more in 296 B followed by Parbhani Moti of three mutagens. The spectrum of chlorophyll mutations comprised albina, xantha, viridis, xanthaviridis, chlorina. The most frequently occurred mutant was viridis type followed by chlorina in all the populations. The population 296 B had expressed largest frequency of chlorophyll mutants followed by Parbhani Moti.

Induction of chlorophyll mutation through physical and chemical mutagen in Phaseolus lunatus (Lima Bean)

The present investigation was undertaken to study the frequency of chlorophyll deficient sectors and chlorophyll mutants induced by Gamma rays at the dosage of 240Gy,300Gy,360Gy,420Gy, Ethyl Methene Sulphate (EMS) at the concentrations of 0.25%,0.50%,0.75%,1% and the Combination of both (Gamma rays and EMS) like 240Gy+1%, 300Gy+0.75%, 360Gy+0.50%, 420Gy+0.25% in the variety ‘King of Garden’ Phaseolus lunatus (lima bean).The chlorophyll mutants were observed in all the three mutagenic treatments in the lima bean. These mutants were White (Albina), Yellow (Xantha), Yellow green (Chlorina) and Light green (Viridis). They were screened after 10-15 days of old seedling and were found at the margin of the leaflet or the entire leaflet.Induced mutation in the sectors of the leaves resulted into chlorophyll chimeric plants. The scoring of chlorophyll mutation frequency in M2 generation was one of the most reliable measures for evaluating the mutagenic induced genetic altercation of the mutagen treatments used in the ideotype. The frequency of chlorophyll mutants increased with the increase in the dose/concentration of the mutants. They can be screened and enhanced through mutation breeding for enormous yield.

Studies on Mutagenic Effectiveness and Efficiency of Gamma Rays and Ethyl Methane Sulphonate in Jasmine

Background/Aim: The present investigation was undertaken to study the mutagenic effectiveness and efficiency in M1V1 generation and to study effect of gamma rays on spectrum of morphological mutation in Jasminum grandiflorum Linn. cv. White Pitchi. Methods: Terminal cuttings were treated with four doses of gamma rays viz., 10, 15, 20 and 25 Gy and four doses of EMS viz., 25, 30, 35 and 40 mM separately. Both mutagens created a high frequency as well as a wide spectrum of mutation. Results: Totally five types of chlorophyll mutants viz., xantha, viridis, yellow viridis, variegata and tigrina were observed. The mutagenic effectiveness and efficiency were calculated based on biological damage as well as chlorophyll mutation frequency on M1 plants. The mutagenic treatments were effective in inducing various types of morphological macro mutants, with few of them showing significant changes in plant height, flowering parameters and flower yield. The lower mutagen doses were associated with higher mutagenic effectiveness and efficiency. Conclusion: The present study indicated that the physical mutagen gamma rays were more effective and efficient in causing mutations as compared to the chemical mutagen EMS.

Induced chlorophyll mutations in bell pepper (Capsicum annuum L. var. grossum)

An investigation entitled “Induced chlorophyll mutations in bell pepper (Capsicum annuum L. var. grossum)” was conducted during kharif (summer-rainy season) 2012 and 2013 at Experimental farm of the Department of Vegetable Science and Floriculture, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, H.P., India. Healthy seeds of California Wonder of bell pepper were exposed to physical mutagen Gamma rays using 60CO as a source of radiation at Mutation Breeding Centre, Department of Biotechnology, BARC Trombay, Mumbai and chemical mutagen EMS (Ethyl Methane Sulphonate) to obtain the spectrum and frequency of chlorophyll mutations in M2 generation. The M1 generation was produced from these mutagen treated seeds. Several unique and interesting chlorophyll and viable mutants were obtained in M2 generation. In M2 generation, gamma rays induced higher proportion of chlorophyll mutants then EMS. A progressive increase in mutation frequency of chlorophyll mutations was observed with increasing doses/concentrations. Four different types of chlorophyll mutants namely xantha, yellow xantha, chlorina and viridis were induced. Out of these mutants, chlorina and viridis were most frequent and were produced even in lower doses/concentrations while yellow xantha was least frequent and produced only in higher doses. The highest frequency of chlorophyll mutations (18.8 %) was reported in the 22 kR of gamma dose, while the lowest (0.80 %) frequency of chlorophyll mutations was found in the treatment of 1.0 % EMS. There was a dose dependent increase in the spectrum and frequency of chlorophyll mutations. These chlorophyll mutants induced by gamma radiation and EMS could be used in mutation breeding programme for inducing viable mutations for improvement of bell pepper varieties.