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  • Author or Editor: S. Sharma x
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The genetics of yield and related traits was studied in barley ( Hordeum vulgare L.) by means of 10 × 10 half-diallel progenies (F 1 and F 2 ) at three sowing dates. An additive-dominance model fitted only for flag leaf area, spike length and 1000-grain weight at different sowing dates. Both additive (D) and dominance components (H 1 and H 2 ) were significant for all the traits studied, indicating the preponderance of dominance components in controlling the inheritance for these traits. The value of (H 1 /D) 1/2 indicated over-dominance for all the traits except for flag leaf area. Values of ‘F’ indicated an excess of dominant alleles in the parents for all traits except for flag leaf area. The environmental component ‘E’ was significant for all traits. The ratio of H 2 /4H 1 indicated the symmetrical distribution of genes for all the traits studied. The value of h 2 /H 2 was less than one for all traits except for spike length, suggesting that a dominant gene was involved in controlling the inheritance of spike length, whereas multiple genes controlled the inheritance of the remaining traits. The heritability estimates were relatively moderate for flag leaf area and 1000-grain weight, but low for all other traits. However, epistatic interactions had an important role in the expression of other traits. Breeding methods such as bi-parental mating in early segregating generations or diallel selective mating may be advantageous to combine important yield component characters for a tangible advance in six-rowed barley.

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The experimental material comprised three crosses, namely Cocorit 71 × A-9-30-1, HI 8062 × JNK-4W-128 and Raj 911 × DWL 5002, generated from six diverse parents. Twelve populations of each of these three crosses revealed that sufficient genetic variation was recorded among generations for all the traits in three crosses. The results of a correlation study demonstrated that the grain yield per plant was significantly and positively associated with peduncle area and flag leaf area in the cross Cocorit 71 × A-9-30-1. However, the spike area had poor correlation with grain yield. In the cross HI 8062 × JNK-4W-128, grain yield per plant was positively associated with peduncle area and spike area, whereas flag leaf area showed a positive but weak association with grain yield. In the cross Raj 911 × DWL 5002, grain yield per plant was positively associated with all three physiological traits studied, indicating that improvement in grain yield may be made by these traits in this material. Peduncle area appeared to be the most important trait in the present study because of its association with grain yield in all three crosses. Although flag leaf area and spike area showed a positive association with grain yield in all three crosses, their relative magnitudes and significance changed from one cross to the other. Correlation studies revealed that selection for peduncle area would lead to high yield in durum wheat. However, due consideration should also be given to flag leaf area and spike area during the selection of plants for further tangible advances in grain yield in durum owing to their positive association with grain yield.

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The results obtained for the parental, F 1 and F 2 generations of a 10 × 10 diallel set (excluding reciprocals) of durum wheat revealed that there were significant differences between all the hundred genotypes for all the characters. The genotypes represented a wide range of expression for almost all the characters. High estimates of GCV (genetic coefficient of variation) were observed for the number of effective tillers, grain yield per plant, harvest index and 1000-grain weight. The low values of GCV recorded for days to heading, grain protein content and plant height indicated their limited scope for improvement. High heritability (h 2 ) values ranging from 92.27% (grain yield/plant) to 99.00% (protein content) were observed for all the characters. The highest expected GA (genetic advance) as a percentage of the mean was manifested for harvest index, followed by plant height, number of effective tillers per plant and grain yield per plant. These traits also possessed high estimates of heritability, indicating that most of the variation in these characters was due to additive gene effects. For protein content high heritability was observed with low genetic gain, indicating non-additive gene effects. Thus, a systematic approach based on selection for harvest index, plant height and number of effective tillers per plant on the basis of high per se performance would be the most effective approach for improving the yield level of durum wheat. The wealth of variability available in the hybrid populations offers good prospects for its improvement in the near future.

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A field study conducted for two years (1995-96 and 1996-97) at the Indian Agricultural Research Institute, New Delhi on a sandy clay loam soil showed that the application of NP increased the total grain production of a rice-wheat-mungbean cropping system by 0.5-0.6 t ha -1 , NK by 0.3-0.5 t ha -1 and NPK by 0.8-0.9 t ha -1 compared to N alone, indicating that the balanced use of primary nutrients was more advantageous than their imbalanced application. The application of farmyard manure (FYM) along with NPK further increased the total productivity of the rice-wheat-mungbean cropping system by 0.3-0.6 t ha -1 , the organic C by 0.13%, the available N by 10.7 kg ha -1 , the available P by 4.7 kg ha -1 and the available K by 15 kg ha -1 compared to NPK after two crop cycles of the system. The results of the present study thus indicate that integrated nutrient management involving FYM and NPK fertilizers is a must for the sustainability of a cropping system.

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Two hundred and forty diverse set of wheat cultivars released in India during the last several decades were evaluated for HMW and LMW glutenin alleles, for assessing their diversity and effect on sedimentation volume and mixograph parameters. Both SDS-PAGE and PCR based markers were employed in identifying alleles encoded at Glu-1 and Glu-3 loci. Extensive allelic variation was observed at both the Glu-1 and Glu-3 loci. There was prevalence of Glu-A1b, Glu-B1i, Glu-D1a, Glu-A3c, Glu-B3b, Glu-B3g and Glu-D3b. The alleles Glu-A1b, Glu-B1i, Glu-D1d, Glu-A3b, Glu-B3g/h and Glu-D3b exhibited high SDS-sedimentation volume. Glu-B1i and Glu-D1d showed highly significant positive effect (p < 0.001) on sedimentation volume and also had additive effects. However, surprisingly overall there was decline in the frequency of Glu-B1i allele during last two decades in Indian wheat breeding and not a single 1B/1R translocation cultivar possessed this allele. Glu-A1b showed significant positive effect on mixograph peak time, peak slope and peak width. Glu-B3g exhibited significantly higher mixograph peak time and width at 8 and Glu-B3h showed higher dough stability. Glu-B3j (1B/1R translocation) exhibited highest peak slope indicating the negative effect on dough strength. This information can be useful in designing breeding program for the improvement of Indian bread wheat quality.

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The success of winter × spring wheat hybridization programmes depends upon the ability of the genotypes of these two physiologically distinct ecotypes to combine well with each other. Hence the present investigation was undertaken to study the combining ability and nature of gene action for various morpho-physiological and yield-contributing traits in crosses involving winter and spring wheat genotypes. Five elite and diverse genotypes each of winter and spring wheat ecotypes and their F 1 (spring × spring, winter × winter and winter × spring) hybrids, generated in a diallel mating design excluding reciprocals, were evaluated in a random block design with three replications. Considerable variability was observed among the spring and winter wheat genotypes for all the traits under study. Furthermore, these traits were highly influenced by the winter and spring wheat genetic backgrounds, resulting in significant differences between the spring × spring, winter × winter and winter × spring wheat hybrids for some of the traits. The winter × spring wheat hybrids were observed to be the best with respect to yieldcontributing traits. On the basis of GCA effects, the spring wheat parents HPW 42, HPW 89, HW 3024, PW 552 and UP 2418 and the winter wheat parents Saptdhara, VWFW 452, W 10 and WW 24 were found to be good combiners for the majority of traits. These spring and winter wheat parents could be effectively utilized in future hybridization programmes for wheat improvement. Superior hybrid combinations for one or more traits were identified, all of which involved at least one good general combiner for one or more traits in their parentage, and can thus be exploited in successive generations to develop potential recombinants through various breeding strategies. Genetic studies revealed the preponderance of additive gene action for days to flowering, days to maturity and harvest index, and non-additive gene action for the remaining six traits.

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Summary

Enantiomeric resolution of two commonly used β-blockers, namely, (±)-propranolol and (±)-atenolol, has been achieved on silica gel layers which were bulkimpregnated with β-cyclodextrin. Solvent systems DMF-ethyl acetate-butanol (3:2:5, υ/υ) and butanol-acetic acid-ethyl acetate-ammonia (5:2:2:0.5, υ/υ) successfully resolved the enantiomers of (±)-propranolol and (±)-atenolol, respectively. The spots were located with iodine vapor. The effects of concentration of the chiral selector and mobile phase variation were also studied.

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Abstract  

Based on solvent extraction and fractional precipitation methods, the retention in iodate and periodate targets were measured. Influence of temperature of irradiation in crystalline and solution phase have been observed. Higher retentions were observed in crystalline solids than in corresponding solution phase irradiation at room temperature. The role of physicochemical properties of the salts and the solvent is discussed.

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