This book covers the various aspects such as morphological characterization and evaluation of mungbean germplasm, laboratory evaluation of PHS resistance using various pod and seed parameters, Identification of PHS resistance/tolerant germplasm, study of association and direct and indirect effect of various characters on pre-harvest sprouting.
Mungbean [Vigna radiata (L.) Wilczek] is one of the important grain legumes of global economic importance. It requires hot and dry climate. Among the three seasons, kharif is most important and in this season pre-harvest sprouting (PHS) is a big problem causing huge losses in production. Nearly 60-70% of yield losses have been reported in green gram and black gram due to PHS. In view of the substantial losses caused by PHS, it is imperative to develop PHS tolerant varieties for yield improvement in mungbean. However, the information on these aspects is lacking because little work has been done on this crop.
CONTENTS
1. INTRODUCTION
2. REVIEW OF LITERATURE
3. MATERIALS AND METHODS
4. EXPERIMENTAL RESULTS
5. DISCUSSION
6. SUMMARY AND CONCLUSION
LITERATURE CITED
PREFACE
Mungbean[Vigna radiata(L.) Wilczek] is one of the important grain legumes of global economic importance. It requires hot and dry climate. Among the three seasons, kharif is most important and in this season preharvest sprouting (PHS) is a big problem causing huge losses in production. Nearly 60-70% of yield losses have been reported in green gram and black gram due to PHS. In view of the substantial losses caused by PHS, it is imperative to develop PHS tolerant varieties for yield improvement in mungbean. However, the information on these aspects is lacking because little work has been done on this crop. This book covers the various aspects such as morphological characterization and evaluation of mungbean germplasm, laboratory evaluation of PHS resistance using various pod and seed parameters, Identification of PHS resistance/tolerant germplasm, study of association and direct and indirect effect of various characters on pre-harvest sprouting.
The present investigation was carried out at Norman E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, India, with 112 diverse genotypes along with 5 checks of mungbean. ANOVA revealed highly significant differences among all the genotypes for all the characters studied. On the basis of germination percent of seeds in pod one genotype viz.Vigna radiatavarsublobata(2.09%), the wild progenitor of cultivated mungbean, was found highly resistant; one genotype PM 06-16 (13.55%) was found resistant, while four genotypes, PM 06-49 (21.39%) , ML 133 (22.01%), Mung local (26.10%) and NM-94 (26.18), were found to be moderately tolerant to preharvest sprouting.
Correlation analysis indicated that germination percent of seeds in pod showed positive significant correlation with seed germination percent, seed diameter, pod length, pod diameter, water absorption percent by pod and 100-seed weight whereas no significant negative correlation was found with other characters. Path coefficient analysis revealed that seed germination percent, number of pods per cluster, plant height, pod length, water absorption percent by seeds, number of leaves and water absorption percent by pods exerted a high order positive direct effect on germination percent of seeds in pod while total number of pods per plant, growth habit, 100-seed weight and pod pubescence exerted high order of negative direct effect on germination percent of seeds in pod.
Abbildung in dieser Leseprobe nicht enthalten
Introduction
Mungbean [Vigna radiata(L.) Wilczek] is one of the important grain legumes of global economic importance. In India, it is the third most important pulse crop after chickpea and pigeon pea. It belongs to family Fabaceae (syn. Leguminoseae) and sub family Papilionaceae. It is believed to have been domesticated fromV. radiatavar.sublobata.Mungbean, also known as green gram, has originated in Indian subcontinent. Bihar is considered as secondary centre of diversity. It is priced among pulse crops as its seeds are high in essential dietary protein, easily digested and produce low flatulence when consumed as food(Lakhanpaulet al.,2000). Mungbean is primarily used asdhal.Green pods are used as vegetables. The seed coat and cotyledons after decortication are fed to livestock and poultry. The dried straw including the pod shells are fed to milch animals. Mungbean adapts well to various cropping systems owing to its rapid growth, early maturity and ability to fix atmospheric nitrogen (N2) in symbiosis with soil bacteria ofRhizobium spp.
The trends of last few years show progressive increase in the demand and production of this crop. Unlike cereals and other pulses, global mungbean growing area has doubled in the last 25 years with an annual rate of 2.5%. Increase in total production and productivity of mungbean in India has been achieved through development of a large number of location and/or season specific improved varieties with resistance to important diseases. In India, mungbean is cultivated over an area of 2.53 m ha with a production of 1.12 m tones and productivity of 367 kg/ha(Anonymous, 2010).
The split bean is known as moong dhal, which is green with the husk and yellow when dehusked. The beans are small, ovoid in shape and green in colour. The English word “mung” derives from the Hindimoong. Mungbean is an excellent source of easily digestible protein (2225%)(Raoet al.,1964). Mungbean grain contains 51% carbohydrates, 26% protein, 10% moisture, 4% mineral and 3% vitamins. Mungbean grains are rich in iron (6 mg per 100g of dry seed). The amino acid profile of mungbean (in g/16g N) comprises lysine (7), cysteine (0.6), metheonine (1), threonine (3.5) and tryptophan (0.4) and is complementary to that of cereal grains(Asaduzzamanet al.,2008). Easy assimilability, short duration of cropping and the ease with which it could be grown as a mixture with other crops makes it superior than other legumes.
Mungbeans are mainly cultivated in India, China, Thailand, Philippines, Indonesia, Burma, and Bangladesh and in hot and dry regions of South Europe and Southern USA(Singh, 2005). In India, mungbean is widely cultivated throughout the plains and also in hills up to an elevation of 1820 m. It is mainly grown in the states of Maharastra, Andra Pradesh, Rajasthan, Orissa, Karnataka, Bihar, Madhya Pradesh and Uttar Pradesh.
Mungbean requires hot and dry climate. Cloudy weather, continuous and heavy rains adversely affect the flowering and podding in mungbean, causing low yields. Mungbean can be grown on well- drained loamy sand to sandy loam soils. The crop is sensitive to alkaline, saline or waterlogged soil. Being a short duration crop, mungbean is cultivated in all three seasons (kharif, rabi and zaid) in different parts of country as a pure crop as well as an associate crop in various cropping systems. Among the three seasons, kharif is most important and in this season pre-harvest sprouting is a big problem causing huge losses in production. Nearly 60-70% of yield losses have been reported in green gram and black gram due to pre-harvest sprouting(Durgaet al.,1997).The pre-harvest sprouting is sometimes referred to as weather damage. Weather damage is a general term used to describe a range of adverse physical and chemical changes that occur in seed following its exposure to rainfall and humidity. In view of the substantial losses caused by pre-harvest sprouting, it is imperative to develop pre-harvest sprouting tolerant varieties for yield improvement in mungbean. However, the information on pre-harvest sprouting is lacking because little work has been done on this aspect of the crop.
Keeping the above facts in mind, the present investigation entitled“Screening of Mungbean (Vigna radiata) Germplasm for Preharvest Sprouting (PHS) Resistance”was undertaken with the following objectives:
1) Morphological characterization and evaluation of mungbean germplasm.
2) Laboratory evaluation of PHS resistance using various pod and seed parameters.
3) Identification of PHS resistance/tolerant mungbean germplasm.
4) Study of association of pre-harvest sprouting with other characters and their direct and indirect effect on pre-harvest sprouting.
Abbildung in dieser Leseprobe nicht enthalten
2. REVIEW OF LITERATURE
Pulses production in the country has witnessed a significant increase during the last decade due to development of high yielding disease resistant varieties and adoption of improved pulse production technologies by farmers. However, the realized yield of pulses is far from their actual potential. Various factors hamper realization of actual yield potential of pulses, amongst them pre-harvest sprouting is an important one. In view of the substantial yield losses caused by PHS in pulses, it is imperative to develop varieties resistant or tolerant to preharvest sprouting by understanding the mechanisms of resistance and to identify the sources of resistance for transferring pre-harvest sprouting resistance into desirable backgrounds.
The attempts understand the mechanisms and inheritance of traits governing resistance to pre-harvest sprouting have been very few. Keeping the meagre information available on this aspect, literature pertaining to pre-harvest sprouting, sources of resistance, and inheritance of PHS resistance in pulses has been reviewed in the following pages.
Differences in water absorption by intact seeds and in osmotic properties of excised seed coats in 4 near-isogenic breeding lines of snap bean,Phaseolus vulgarisL. was measured byWyatt (1977). He concluded that white seeds absorbed water more rapidly than coloured seeds. Excised white seed coats were more permeable to water than coloured seed coats in response to an osmotic gradient.Krul (1978)observed an inhibitory effect of substances within the soybean pod on water imbibitions by the seed. Park and Yang (1978)concluded that avoidance of pre-harvest sprouting also contributes to the reduction of pre-harvest losses. Selection for synchronous maturity has been effective in mungbean, as it reduces the vulnerability in the field.
Rolston (1978)concluded that hot dry weather tends to increase the proportion of hard seeds and thus improves resistance to preharvest sprouting and quality for storage.Tekronyet al.(1980)observed that the visual characteristics of seeds and testae were more sensitive than viability to deterioration from exposure to weathering. He recommended selection for thick and/or dense pod walls in soybean.Caleroet al.(1981)through electron microscopy revealed that seed coats of soybean cultivars differ in pore number, pore type, and the amount of cuticle wax. Impermeable-seeded genotypes have no pores in the epidermis of the seed coat.
Imrieet al.(1981)observed that in mungbean, the stage of ontogeny of racemes and pods can vary enormously both within and among plants and genotypes. So, this may allow genotypes, plants, racemes, and pods in the field to be exposed to differing degrees of weathering prior to screening. The resistance of these materials to subsequent weather damage then becomes confounded both by the timing of the weathering event relative to plant ontogeny, and by the perhaps differing levels of weather damage incurred prior to screening. Therefore, the innate resistance of genotypes to weather damage can be assessed only by subjecting fully protected material to controlled conditions of weathering.
An evaluation of moisture absorption by soybean [Glycine max(L.) Merr.] was conducted byYaklichet al.(1981)in 1978 and 1979. Forty-six cultivars representing Maturity Groups II through VI were grown to harvest maturity in field. Representative plants from each cultivar were taken to the laboratory and intact pods were removed from each plant. In each year, two sets of 20 pods from each cultivar were submerged in water for 0, 1, 6, and 24 hours to allow moisture uptake by the pod and seed. Pods and seeds from cultivars in Maturity Groups II through IV absorbed significantly more moisture than those from Maturity Groups V and VI. Pods of ‘Williams' and ‘Celest' absorbed the least amount of moisture in Maturity Groups III and V, with both having absorbed approximately 78.0 g H2O/100 g dry wt. at 24 hours. Water uptake in these two cultivars was significantly different from the cultivars that absorbed the most water within their respective maturity groups. Seed of ‘Perry' and ‘Ware' absorbed the least moisture of the 16 cultivars in Maturity Groups IV.
Andrews (1982)described damage range for pulses which ranges from wrinkling and discoloration of the testa to sprouted and/or mouldy seed. Only unblemished or very mildly damaged seeds are suitable for usage while wrinkled and slightly discoloured seed can be dehulled for use as dal. More severely damaged seeds are unfit for consumption.
Kueneman and Dassou (1982)screened soybeans for resistance to pre-harvest sprouting by placing pods at physiological maturity in an incubator at 300C and 90-95% RH for 10 days. Seeds were evaluated for laboratory germination and field emergence. This system proved more successful in selecting for resistance to pre-harvest sprouting than delayed harvest in that it minimized the effect of sowing date, had a small error variance, and reduced the effect of variation in pod maturation within and plants because pods of similar ages could be selected for the test.Tully (1982)reported genotypic variation in soybean for pod permeability to water. He found an 11-fold difference in the permeability of ‘Arksoy' pods compared to those of ‘Rose NonPop'. Pod traits such as thickness, amount of cuticle wax, and susceptibility to shattering can affect permeability to water.
An experiment to determine the amount of genotypic variation for resistance to pre-harvest sprouting was conducted byDoughertyet al.(1984). The percentage of pods ruptured by sprouting seed (PR) was measured and pod rupture was adjusted for initial seed germination (APR) on 40 genotypes for 3 years. The pods were produced in the field and screened for resistance in the greenhouse by using a mist chamber. Pods were misted for 4 min periods 22 times/day for 7 days. Genotypic variation within maturity groups was found for PR, APR, post-treatment seed germination (PTSG), and post-treatment seed quality. Genotypes with the most resistance to pre-harvest sprouting were: D65-8232 (impermeable seed coat) and ‘Hale 3', Maturity Group (MG) V; ‘Lancer' and ‘Tracy', MG VI; ‘McNair 800', MG VII; and ‘Dowling', MG VIII. The partial correlation coefficient, with the effect of year and maturity removed, between APR and PTSG was negative (r=- 0.39). Resistance to pre-harvest sprouting was associated with slower water uptake by seed.
Lassimet al.(1984)observed that dew, high humidity and rainfall during maturity period increases atmospheric moisture, which is absorbed by dry pods and seeds and leads to testa expansion and an increased seed respiration rate. Subsequently drying during periods between rainfall causes testa shrinkage and return of seeds to a physiologically inactive stage which leads to discoloration and cracking of testa, loss of cell membrane integrity and leakage of cell contents, reduced weight and ultimately deteriorates the quality of the seeds. Thus the weather damaged seed is more prone to fungal infection and to cracking during harvesting and threshing.
Williams (1984)screened mungbeans for pre-harvest sprouting and revealed that the lines which were resistant had no hard seeds. The lines which were resistant to pre-harvest sprouting had thick pod walls with the presence of epicuticular wax.Davidson (1985) and Imrieet al.(1987)concluded that hard seededness is a specific character and is one of the approaches to solve the problems of preharvest sprouting in green gram.
Imrieet al.(1987)reported that the inheritance of hard seededness may be dominant, partial dominant and recessive depending on the parental source. He further reported low heritability for the character which indicates that this trait is highly influenced by environment and little improvement can be achieved through selection.Lawnet al.(1987)reported a source of hard seededness, namely,Vigna radiatavar. sublobata, the wild progenitor of cultivated greengram. Accessions with 100% hard seed levels have been reported, and the trait has been found to be under the control of a single dominant gene.Satyanarayana (1987)found that in mungbean, PHSR-85 (LGG-450 induced mutant) was resistant to pre-harvest sprouting by virtue of higher epicuticular wax on the pod wall surface.
Satyanarayana (1991)observed the other pod characteristics which impart resistance to pre-harvest sprouting and the characters are beak length of pod, beak angle, pod wall thickness, and rate of water imbibitions through pod wall.Cheralu (1995)suggested that in mungbean, a tall genotype having short duration bearing more number of long pods,with high pod wall epicuticular wax and small beak with moderate to high percent hard seed should be selected for developing resistance to pre-harvest sprouting coupled with high yield.
Williamset al.(1995a)conducted an experiment to describe the causes, process and effects of weathering in mungbean as a step towards the breeding of resistant cultivars. Symptoms of weather damage were produced by exposing plants to simulated rainfall/high humidity and by subjecting seeds to cycles of wetting and drying. In both cases, symptoms progressed from discolouration, wrinkling, and cracking of the testa, to germination of the seed. Symptoms produced in controlled experiments were the same as those observed in the field. Only seeds that imbibed water during the wetting phase developed symptoms of weather damage on drying. Exposure to one cycle of weathering also advanced the timing and degree of damage to seeds during subsequent cycles. This was associated with an increased rate of water absorption in weathered seeds.
Williamset al.(1995b)described the effect of weathering on the electrical conductivity of leachate from exposed seeds and evaluated this technique (Electrical Conductivity of Seed Leachate as an Assay of Level of Damage) as a means of discriminating among levels of weather damage. Seeds were weathered in the field or immersed in water in the laboratory for varying durations during one or more cycles of wetting and drying. Leachate conductivities generally increased with increasing visual damage and decreasing viability of seeds. When measurements of conductivity were delayed, the results appeared to be confounded by the extent to which solutes were lost during previous exposure to weathering. Measurements soon after immersion tended to reduce this effect and to better reflect the level of weather damage in seeds of mungbean. So, it was concluded that leachate conductivity technique can provide a reliable assay of weather damage in mungbean.
Williamset al.(1995c)concluded that cultivars differ in their resistance to weathering, but selection for resistance based on field response has been unsuccessful. Three controlled experimental systems (immersion in water, exposure to simulated rainfall, and exposure to cyclic wetting and drying in a mist chamber) were evaluated for their ability to reproduce the symptoms of weather damage and to differentiate among the responses of cultivars known from field experience to differ in resistance. When seeds were immersed, the susceptible green gram cv. Berken absorbed water faster and had less impermeable seed than the resistant black gram cv. Regur. The green gram cv. Celera showed an intermediate response consistent with its intermediate resistance to weathering. The rainfall simulator produced more realistic conditions for weathering than seed immersion, and symptoms typical of weather damage were produced. However, the responses of cultivars were relatively poorly differentiated and the method showed poor repeatability. The exposure of podded racemes to wetting and drying cycles under controlled conditions of temperature and humidity in a mist chamber provided the most reliable method for simulating weather damage. The degree of damage increased with duration of exposure and the relative resistance of cultivars was consistent with field observation. The extent of weather damage was best measured as reduction in seed viability and as change in the appearance and permeability of the testae of seeds following exposure. The combined use of mist chamber and these measurement criteria constitute a successful system for the selection and breeding of mungbeans for resistance to pre-harvest weathering.
Combining ability of 30 crosses, obtained from 5 lines and 6 testers, for pre-harvest sprouting in mungbean was analysed byCheraluet al.(1999). Genetic analysis indicated the predominance of additive gene action for pod beak length, pod wall thickness and pod wall epicuticular wax, while hard seed per cent and pre-harvest sprouting were under the control of non-additive gene action. Both additive and non-additive gene actions were found to operate for moisture absorption rate through the pod wall. Among the lines LGG-450, LGG-440 and among testers ML-267, Pusa-105 and MGG-295 were found to be good general combiners for the traits responsible for resistance to pre-harvest sprouting. Five crosses viz., LGG-450 x PDM-54, LGG-450 x LGG-407, LGG-440 x LGG-407, K-851 x MGG-295 and V-2764 x Fusa-105 were found to be the best specific combiners for developing pre-harvest sprouting resistant progenies in mungbean.
Cheraluet al.(2002)in their study evaluated thirty crosses of mungbean and their parents (5 lines and 6 testers) in Warangal, Andhra Pradesh, India, during the rainy season of 1993 for heterosis for seed yield and pre-harvest sprouting. Heterobeltiosis in the desirable direction was recorded for seed percentage, pre-harvest sprouting, and moisture absorption through pod wall. LGG 440 x Pusa 105, LGG 440 x PDM 54, LGG 440 x MGG 295, and PS 16 x WGG 2 registered significant negative heterobeltiosis with non-significant inbreeding depression for moisture absorption through pod wall (48 h of soaking). LGG 550 x WGG 2 and LGG 450 x MGG 295 showed significant heterobeltiosis with non-significant inbreeding depression for pre-harvest sprouting. Significant negative heterobeltiosis with nonsignificant inbreeding depression for pre-harvest sprouting, and significant positive heterobeltiosis and non-significant inbreeding depression for seed yield were observed in LGG 450 x MGG 295.
Vijaylaxmi and Sanjeev (2008)identified five genotypesviz., TARM 1, TARM 18, Ganga Mung, Pusa Vishal and Pusa 9072 showing tolerance to pre-harvest sprouting through screening of 28 mungbean genotypes under field and laboratory conditions. Pods of these genotypes failed to show any seed germination when they were subjected to constant water sprinkling for 72 hours, wrapped under moist towel for 96 hours, or when the pods were kept on moist filter paper at 280C in BOD incubator. However, when seeds (without pod walls) of these tolerant genotypes were subjected to germination on moist filter paper and/or on moist sand bed(s), they showed germination around 85-90%.
Reddyet al. (2010)identified the pre-harvest sprouting tolerant mutant in mungbean. For this TARM-1 variety was irradiated with 450 Gy gamma rays and raised M1 generation. The M2 generation seeds were screened but no mutant could be identified for pre-harvest sprouting resistance (PHSR) or tolerance. In M3 generation three PHSR mutants were isolated and true bred by growing up to M7 generation.
Abbildung in dieser Leseprobe nicht enthalten
3. MATERIALS AND METHODS
The present investigation entitled “SCREENING OF MUNGBEAN GERMPLASM FOR PRE-HARVEST SPROUTING RESISTANCE” was carried out at the N. E. Borlaug Crop Research Centre of G. B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India. Geographically Pantnagar is situated at 29.00N latitude and 79.300E longitude and at an altitude of 243.84 m above the mean sea level. This falls in the humid subtropical zone and situated in the Tarai belt in the foothills of Shivalik range of the great Himalayas. The laboratory experiment was carried out at the Pantnagar Centre for Plant Genetic Resources, Pantnagar. The details of materials used, experimental design, statistical techniques followed and laboratory procedures adopted during the course of this investigation have been presented as follows:
3.1 EXPERIMENTAL MATERIALS
The experiment was conducted during the Rainy season, 2010 at the N. E. Borlaug Crop Research Center, Pantnagar. The experimental material for the present study consisted of 112 germplasm lines ofVigna radiataalong with 5 checks. The germplasm strains selected for the investigation were genetically diverse and exhibited wide range of variation for the qualitative and quantitative characters. The detailed information about genotypes and checks has been presented in table 3.1.
Table 3.1 Details of mungbean germplasm used
3.2 EXPERIMENTAL DESIGN
The field experiment was laid out in an Augmented Block Design. The material was planted in single row plots on 9th August 2010. The spacing between the two germplasm was kept 30 cm and plant to plant distance was kept 10 cm. All 112 accessions were assigned in 4 blocks with 5 checks repeated in every block.
The laboratory experiment was conducted in Randomized Block Design with 3 replications for each genotype.
3.3 OBSERVATIONS RECORDED
3.3.1 Observations on plant
Observations were recorded on the whole plot basis for plant habit and days to 50 percent flowering, whereas the characters like plant height, number of branches, number of clusters, number of pods per cluster, total number of pods per plant and number of leaves were taken on five randomly selected competitive plants from each line. The average values for these plants were calculated and used for the statistical analysis. The techniques employed to record data on individual characters are described as follows:
I. Hypocotyl pigmentation:It was recorded at seedling stage after 8-10 days of sowing under the following categories-
Absent-1
Present-2
II. Days to 50 percent flowering:Number of days taken from the date of sowing to the appearance of 50% flowering in a plot was recorded.
III. Plant height (cm):Plant height was measured in cm. with the help of meter scale from the base to the tip of the plants on 5 randomly selected plants in each plot at maturity.
IV. Growth habit:The data on plant habit recorded at 45 days after emergence on 5 randomly selected plants as-
Determinate-1
Semi-determinate-2
Indeterminate-3
V. Number of branches:Total number of branches was counted on 5 randomly selected plants and average was taken.
VI. Number of clusters:Number of clusters bearing pods was counted on 5 selected plants and average was taken.
VII. Pods/cluster:Number of pods present on each cluster was counted and average was taken.
VIII. Pods/plant:Total number of pods was counted from each randomly selected plant.
IX. Number of leaves:Total number of leaves was counted from each randomly selected plant and average was taken.
3.3.2 Observations on pods-
Pod pubescence, pod length, pod diameter and pod wall thickness were recorded on 10 randomly selected pods in each entry, whereas water absorption percent by pods and germination percent of seeds in pod were recorded on three sets (replications) of 10 randomly selected pods in each genotype.
I. Pod pubescence:The data for pod pubescence were recorded as-
Less pubescent-1
Moderately pubescent-2
Densely pubescent-3
II. Pod length (cm):The length of 10 randomly selected pods was measured in centimeter by using scale and the average was taken.
III. Pod diameter (mm):It was measured by using digital Vernier caliper and average was taken.
IV. Pod wall thickness (mm):thickness of pod wall was measured in millimeter by using digital Vernier caliper.
V. Water absorption percent by pods:The data on water absorption percent were taken on the basis of dry weight and wet weight (after soaking pods in water for 24 hours) of pods. Pods dry weight and wet weight were taken in gram and the water absorption percent was calculated as:-
Water absorption %= [(wet weight - dry weight)/dry weight] x 100
VI. Germination percent of seeds in pod:Number of seeds germinated in pods after 48 hours of incubation in germinator maintained at 24oC and total number of seeds in each pod were counted and pod germination percent was calculated as:-
Germination %= [No. of seeds geminated/Total no. of seed] x 100
3.3.3 Observations on seeds-
Seed length and seed diameter were recorded on 10 randomly selected seeds in each entry, while 100-seed weight, seed density, water absorption percent by seed and seed germination percent recorded on three sets (replications) of 100 randomly selected seeds in each entry.
I. Seed length (mm):Seed length was measured in millimeter using Vernier Caliper and average was taken.
II. Seed diameter (mm):The diameter of 10 randomly selected seeds was measured in millimeter with help of Vernier Caliper.
III. 100-Seed weight (g):The dry weight of 100 randomly selected seeds from each entry was measured in gram.
IV. Density (g/ml):The volume of 100 seeds was measured in milliliter by using measuring cylinder and density was calculated as-
Density= dry weight/volume
The unit of measurement was g/ml.
V. Water absorption percent by seeds:The data on water absorption percent by seeds was taken on the same lot of 100 seeds used for the preceding two observations. The seeds were soaked in water for 6 hours and their wet weight was recorded in gram and the water absorption percent was calculated as-
Water absorption %= [(wet weight - dry weight)/ dry weight] x 100
VI. Seed germination percent:The same set of 100 seeds used for recording the preceding observation was incubated for 30 h in a Seed Germinator and the number of germinated seed counted. The seed germination percent was then calculated as-
Seed germination percent= (Number of germinated seed/100) x 100
[...]
- Quote paper
- Sarfraz Ahmad (Author), Vikas Belwal (Author), 2011, Pre-Harvest Sprouting in Mungbean. Screening Vigna radiata Germplasm and Correlation Study, Munich, GRIN Verlag, https://www.grin.com/document/1245070
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