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Author: Basha, M Hussain × End date: 2016 × Start date: 2010 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Induced mutagenesis for economically desirable traits in oat (Avena sativa L.)
    (JNKVV, 2016) Basha, M Hussain; Mehta, A.K.
    The present investigation was carried out to study the response of three oat varieties (JO-1, Kent and JO-03-91) to biological effects of gamma irradiation, ethyl methane sulphonate (EMS) and their combinations in M1 generation, estimation of mutation frequency and spectrum in M2 generation, selection and identification of oat mutants for phenological and economically desirable traits, screening of oat mutant lines for drought tolerance in M3 generation and assessment of genetic diversity in oat mutant lines using RAPD and ISSR markers. The germination (%), root and shoot length (cm), seedling emergence (%) at 7th and 14th DAS and plant survival (%) decreased with the increasing doses of gamma rays. The decrease was neither proportional to the increase in doses nor definite pattern was revealed in all three oat varieties except seedling height (cm) at 7th and 14th DAS; plant height (cm) and seed fertility (%) decreased in near linear fashion. While in EMS treatments, all the traits linearly decreased with the increasing concentration and in combination treatments (Gamma + EMS) the decrease was observed in near linear fashion. In gamma radiation treatments, fifty percent of growth reduction (GR50) was observed in graphical intersect at 410 Gy in the variety of JO-1, 480 Gy in Kent and 350 Gy in JO-03-91. In case of EMS treatments, fifty percent of growth reduction (GR50) was recorded at 0.65% EMS in the variety of JO-1, 0.68% EMS in Kent and 0.62% EMS in JO-03-91. Similarly in gamma + EMS combination treatments, fifty percent of growth reduction (GR50) was observed at 275 Gy + 0.4% EMS in the variety of JO-1, 280 Gy + 0.4% EMS in Kent and 265 Gy + 0.4% EMS in JO-03-91 In gamma radiation treatments, fifty percent plant survival reduction (LD50) was observed at 535 Gy, 475 Gy and 425 Gy in Kent, JO-1 and JO-03-91 from plant survival (%) and at 410 Gy, 246 Gy and 230 Gy in Kent, JO-03-91 and JO-1 from seed fertility (%). In case of EMS treatments, LD50 values were recorded at 0.86%, 0.65% and 0.63% in Kent, JO-03-91 and JO-1 from plant survival (%) and at 0.85%, 0.83% and 0.4% EMS in Kent, JO-1 and JO-03-91 from seed fertility (%). Similarly in gamma + EMS combination treatments, LD50 values recorded at 410 Gy + 0.4% EMS, 355 Gy + 0.4% EMS and 315 Gy + 0.4% EMS in Kent, JO-1 and JO-03-91 from plant survival (%), and 230 Gy + 0.4% EMS, 185 Gy + 0.4% EMS and 180 Gy + 0.4% EMS in Kent, JO-03-91 and JO-1 from seed fertility (%). Based on GR50 and LD50 values, the varieties JO-03-91 and JO-1 were found relatively more sensitive to mutagens than the Kent variety. Total eleven chlorophyll mutations (Xantha, yellow viridis and chlorina) observed in all the three varieties and morphological mutations were observed only in JO-03-91 variety, It has seven morphological mutations mainly categorized into two [laxatum (lax) and erctoides (ert)] were found at different doses of gamma radiation, EMS and in combination treatments. The frequency of chlorophyll and morphological mutations were high in EMS and combination treatments than gamma radiation treatments alone. The relative mean frequency and spectrum of chlorophyll mutants based on mutagen basis (Pooled over varieties), the gamma + EMS combination treatments induced high mutation frequency (22.00%) followed by EMS (14.32%) and gamma rays (12.74%). Thus, It concluded that EMS proved to be more effective than gamma rays. Thus, the trend of mutagen effectiveness was in the order of gamma + EMS > EMS > gamma rays. The maximum efficiency was recorded in combination treatments at 250 Gy + 0.4% EMS Gy and 300 Gy + 0.4% EMS doses in JO-1 (21.30% and 18.39%), 300 Gy + 0.4% EMS Gy and 350 Gy + 0.4% EMS doses in JO-03-91 (18.20% and 16.91%) and 250 Gy + 0.4% EMS Gy and 300 Gy + 0.4% EMS doses in Kent (15.78% and 15.52%). In case of gamma rays, the maximum gamma radiation efficiency was recorded at 350 Gy in the variety of Kent (18.40%) and 400 Gy in both JO-1 (14.55%) and JO-03-91 (15.63%) varieties. Similarly, in EMS treatments, the maximum EMS efficiency was recorded at 0.4% in the both oat varieties JO-1 (11.26%) followed by JO-03-91 (10.31%) and 0.8% EMS in Kent (10.20%). Therefore, the order of mutagenic efficiency was gamma + EMS > gamma rays > EMS. But the order of mutagenic efficiency deviated from the trend of mutagenic effectiveness. The frequency and spectrum of chlorophyll mutations were fairly high in all varieties of oat. The trend of relative frequency of different chlorophyll mutations was same in all three oat varieties as well as in mutagen basis, it can be represented as albina > xantha > viridis > striata > tigrina > others > maculata respectively. Based on variety basis, the overall frequency of chlorophyll mutations was highest in JO-03-91 (97.27%) followed by JO-1 (90.47%) and Kent (83.62%) respectively. Thus, the general trend of sensitivity of varieties can be represented as JO-03-91 > JO-1 > Kent. In M2 population morphological mutations were observed at different growth stages. In total, 2064 mutants in 17 categories were identified with a frequency of 4.57%. Among the identified mutants, those with the appearance of loose panicles (Lax) and broad leaf mutants were highest with 206 (0.46%) preceded by compact panicle-Ert (0.41%), basal hairiness (0.34%), tall (0.31%), fused leaf (0.29%) in which twin (0.17%) and triple (0.12%), awnless (0.28%), narrow leaf and early type (0.27%), late and semi-dwarf mutants (0.26%), double or multiple panicle (0.23%), anthocyanin pigments and double leaf mutants (0.21%), dwarf (0.20%), higher no. of tillers (0.12%). The mean values of flag leaf width, penultimate leaf length, penultimate leaf width and peduncle length shifted in both the directions, negative mean shift observed in higher doses of gamma rays and combination treatments and positive mean shift recorded in remaining doses of gamma, combination doses and both EMS concentrations in both JO-1 and Kent varieties. Whereas, in JO-1, mean penultimate leaf width shifted in negative direction in medium and higher doses of combination treatments. Similarly, in JO-03-91, mean peduncle length shifted in negative direction in medium and higher doses of gamma rays and combination treatments. . The highest (>20%) GCV and PCV values were recorded for flag leaf length, flag leaf width, penultimate leaf length and peduncle length at different doses of gamma rays, EMS and gamma + EMS combination treatments. High heritability coupled with high genetic advance as per cent of mean was recorded for days to flower initiation, plant height, stem girth, internode length, flag leaf length, flag leaf width, penultimate leaf length, penultimate leaf width, peduncle length, panicle length and 1000 seed weight at different doses gamma rays, EMS and gamma + EMS combination treatments of the three oat varieties. The mutants MO-3, MO-8, MO-16, MO-18, MO-19, MO-20, MO-28, MO-29, MKO-26, MJO-2, MJO-26 and MJO-40 showed increased root length, fresh root weight and dry root weight under water stress condition. Principal component analysis (PCA) was performed on nine drought seedling traits. The first five principal components with drought traits in oat mutants under study indicated drought tolerance. Among these 7 mutants i.e. MO-11, MKO-9, MKO-14, MKO-22, MKO-26, MJO-25 and MJO-30 had more than 0.5 PC values in three principal components could be directly or indirectly utilized in oat improvement programme. All RAPD and ISSR markers used in the current study had highly informative PIC values (>0.50). The genetic diversity analysis revealed that highly diversified induced mutants like M7 (Dwarf + Late), M10 (Anthocyanin Pigmented) and M14 (Awnless).