INDUCTION OF DORMANCY IN GROUNDNUT - A Review

V.R Shelar, Jayadeva. B and A.P. Karjule Seed Technology Research Unit

MPKV, Rahuri-413722, Dist- Ahmednagar (MS) India.

Groundnut (Arachis hypogaea L.) is an important oil seed crop of grown during

summer season. The area under summer irrigated groundnut is fast increasing though it's

yields are very low as compared to USA and China. Several reasons could be ascribed to

its low productivity of which nearly 20 per cent loss in the field is by the in situ

germination due to lack of dormancy (Anonymous, 1979). There is a need to identify

sources of short duration with certain period of dormancy to minimize yield losses due to

in situ germination (Ashok Kumar, 1989 and Patil et al., 1991).

Types of dormancy

The seed dormancy indicates the inability of the seeds to germinate even under

favourable conditions. It is fairly obvious that more than one cause might be responsible

for the dormancy of a seed. In a broad view, two types of dormancy can be distinguished

i.e. (1) "Innate' dormancy where the seeds will not germinate even under favourable

conditions and (2) Imposed dormancy where seeds will not germinate when conditions

are unfavourable. Several forms of innate dormancy have been recognized. Seeds may

fail to germinate because of impermeable seed coat to water (Matthews, 1976).

Factor influencing seed dormancy in groundnut

Seed dormancy in groundnut is controlled by many features. Different causes of

seed dormancy in groundnut have been reported by many workers.

1. Presence of inhibitors and ratio between growth promoters to inhibitor

In recent years the presence of naturally occurring growth inhibitors have

received increased attention which is supposed to play an important role in induction and

termination of dormancy. Amen (1968) has developed a general model for seed

dormancy based on the assumption that the state of dormancy is determined by the

balance between growth inhibitors and growth promoters. Nagarjun and Gopalkrishnan

(1958) reported that non-dormant seeds of TMV-2 groundnut contained a water soluble

growth promoting hormone and the seed extract induced root initiation in the dormant

seeds of TMV-3 groundnut. The physiological studies done by Sreeramulu and Rao

(1971) revealed that the water soluble hormone was indole acetic acid which has root

inducing activity. This auxin was noticed at high levels in the embryonic axis and seed

coat of non-dormant seed.

2. Genetic aspects of dormancy

Dormancy, the physiological phases in seed, is initially determined by the genetic

make up of the seed and varies largely among species and even within a species. The

variation may be expressed in the strain which is used for the improvement of varieties.

Hull (1937) reported that dormancy in groundnut is an inherited character and the rest

period extended even upto two years in some varieties. John et al. (1950) pointed out

that dormancy is an inherent property of Virginia groundnut. The trait dormancy was

found to be partially dominant over the trait non-dormancy. Genetic differences in seed

dormancy between strains with different botanical groups have been demonstrated for

several investigators (Ramachandran et al., 1967 and Lin and Lin, 1971b).

3. Mechanical restriction of the seed coat

Hardness or impermeability of seed coat is said to be one of the many causes for

dormancy. This causes physical restriction to the exchange of gas and water which are

essential for the initiation of germination process. The inheritance of hard seed coat

varies among and within the species. This dormancy is also mediated by environment

prevailing during seed ripening period. Significant morphological differences in the testa

among the different cultivars of groundnut were reported. The seeds of ‘starr’ variety

showed relatively thin compact testa while that of Virginia type is thicker (Gulek et al.,

1977).

4. Presence of ethylene

Ethylene was involved in the normal regulation of seed dormancy (Toole et al.,

1964). Ketring and Morgan (1969) reported that the embryonic axis of non-dormant

seeds of peanut actively produced ethylene during germination, where as ethylene

production was low in dormant seeds.

Maleic hydrazide for inducing dormancy

Maleic hydrazide (diethanolamine salt of 1,2-dihydroxy-3,6 pyridazine-dione), a

growth inhibitor has been successfully used to induce dormancy and thus to reduce

sprouting losses in potato, sugarbeat, onion, carrot and rice. However, the information

available on the effect of MH in inducing seed dormancy in groundnut is meager and

inconclusive. Schoene and Hoffmann (1949) reported the growth inhibiting and

herbicidal properties of maleic hydrazide. The effectiveness of MH in preventing

sprouting of potato tuber was first reported by Zukel (1950). Naylor and Davis (1950)

found that MH was uniformly effective as a growth inhibitor both for dicotyledonous and

monocotyledonous plants

Vaithialingam and Rao (1973) reported that induction of dormancy in TMV-2

bunch groundnut by the foliar application of MH-30, in a field trial conducted at

Coimbatore. Nagarjun and Radder (1983) reported that foliar application of MH could

induce dormancy in bunch type of groundnut variety in the field trials. Gupta et al.

(1985) reported that induction of dormancy in bunch type of groundnut variety T-64 by

the foliar spray of MH in the field trials conducted at Allahabad. Appalanavidu and

Murthy (1961) reported that the maleic hydrazide (MH) was found to be successful in

inducing dormancy in tubers, bulbs and seeds and also in increasing the yield of Ragi.

Maleic hydrazide concentrations for induction of seed dormancy

The concentration of MH is important in obtaining the higher degree of

dormancy.

Krishnamurthy (1969) conducted the pot culture experiment and revealed that

foliar spray of 500 ppm MH at 15 and 25 days prior to harvest induced dormancy in two

varieties of bunch groundnut (Spanish improved and TMV-2). The number of sprouts

reduced from 13.3 to 1.8 in Spanish improved and 17.5 to 5.8 in TMV-2. In a field trial

he observed the induction of dormancy in Spanish improved with 200, 400 and 600 ppm

concentrations of MH sprayed at 75, 81 and 106 days after sowing. Sprouting was 10.3,

12.7 and 10.5 per cent due to 200, 400 and 600 ppm concentrations respectively as

compared to that of unsprayed control (25.6 %). On the basis of this he recommended to

use 200 ppm, as the higher concentrations further did not induce dormancy appreciably.

Vaithialingam and Rao (1973a) reported that foliar application of MH induced dormancy

irrespective of the stage of application. The MH sprayed @ 5000 ppm at 70 DAS, 15000

ppm at 80 DAS and 10,000 ppm at 90 DAS induced dormancy ranging from 30 to 40 per

cent. At 30 DAH, the dormancy effect was greatly reduced. Vaithialingam and Rao

(1973b) studied the induction of seed dormancy in non-dormant groundnut. The MH-30

application as foliar spray was done at 0, 5000, 10000, 15000, 20000, 25000 and 30000

ppm at 70, 80 and 90 DAS. Revealed that irrespective of stages of application, all the

treatments reduced the germination of the non-dormant seeds severely and increased the

total free amino acid content while inducing dormancy.

Nagarjun et al. (1980) conducted a field trial with bunch groundnut to study the

optimum stage and concentrations of MH for foliar spray on the seed quantity and

subsequent growth of seedlings. They reported that there was a reduction in seed

moisture content due to foliar spray of 250 ppm MH in the early stage of crop growth (60

days). However, the MH application did not show any effect on seed purity, seed

viability and seed protein content and seedling growth, while MH at concentrations

greater than 500 ppm increased oil content significantly. Nagarjun and Radder (1983a)

observed that foliar spray of maleic hydrazide (MH) after 60 days of sowing was found to

be superior in inducing seed dormancy compared to later stages of MH application (75

and 90 days of crop growth). The concentrations ranging from 250 to 1000 ppm

remarkably enhanced the seed dormancy to the extent of 60-80 per cent. However,

application of MH in lower concentrations (250 ppm) but at an early stage of crop growth

(60 days) was found to be as good as that of higher concentrations in inducing seed

dormancy. Reduction in moisture content and the rate of catalase enzyme activity were

in association with increase in the degree of induced seed dormancy.

Gupta et al. (1985) have reported that a foliar spray of MH @ 15 x 103 or 20 x 103

ppm applied to groundnut variety (T-64) at 90 days after sowing induced the seed

dormancy. Bhapkar et al. (1986) revealed that a foliar application of MH-30 at different

concentrations viz., 5000 ppm at 70 DAS, 10000 ppm at 90 DAS induced seed dormancy

ranging from 30 to 40 per cent. Abrar and Jadhav (1991) reported that the seed

dormancy period was increased from 5 to 25 days in cv. PI-139915 and PI-169292 by

200 ppm MH applied as foliar spray one month before harvesting. Jagatap (2000) studied

the induction of seed dormancy in bunchy groundnut genotypes viz., RHRG-12, TAG-24,

RHRG-16 and SB-XI. He revealed that seed dormancy could be induced upto 30, 10, 30

and 20 days, respectively by foliar application of MH @ 250 ppm than other

concentrations of MH applied viz., 500 and 750 ppm. He also noticed that reduction in

seedling vigour index and seedling dry weight due to dormancy induction. The 100

kernel weight (g) was increased and seed viability remains unaffected due to MH spray

@ 250, 500, 750 ppm in all the genotypes. Nautiyal (2004) studied the induction of seed

dormancy in non-dormant groundnut cultivars using foliar spray of MH at various

concentrations and reported that foliar spray of malic hydrazide @ 1000 ppm, 60 days

after crop emergence was found to be superior in inducing dormancy in Spanish

groundnut cultivars.

Seed dormancy period in bunch groundnut varieties

Kramer and Kozlowski (1960) reported that the dormant nature of seed appears to

vary according to the geographic spread of species or genera. Gavrielith (1962) reported

that the dormancy period of a variety changes from year to year. Varisai and Dorairaj

(1968) screened 206 groundnut varieties under irrigated condition for dormancy. Only 6

bunch varieties had a dormancy period of about 15-20 days. None of the bunch varieties

studied was completely dormant. Bailey et al. (1972) reported that the Spanish and

Virginia genotypes showed as much as 70 per cent seed dormancy and one Virginia

genotype as little as 3 per cent. Narasimha Reddy and Swamy (1977) studied

gibberellins and germination inhibitors in viable and non-viable seeds of peanut and

reported that the more acidic and basic germination inhibitors were present in viable

seeds. Loss of viability is associated with presence of inhibitors and absence of

gibberellin like substances.

Reddy et al. (1985) studied 17 groundnut varieties belonging to Spanish and

Valencia botanical groups reported that the derivative of the cross, J-11 x Robout-33-1

was found to possess seed dormancy for a period of about 35 days. Pandya and Patel

(1986) studied seeds of 4 Virginia and 73 Spanish bunch varieties and 5 Spanish x

Virginia hybrids for percentage germination after 3-50 days of storage at room

temperature. Virginia types and their crosses, particularly G-201, ICGS-6, Robout-33-1

and (TMV 10 x Robout-33-1)-2, were more dormant than most of the Spanish types

tested. Among the Spanish varieties, RSHY-6, ICGS-21, ICGS-30, ICGS-57, TG-9 and

TG-17 were identified as sources of dormancy for breeding. Kamala et al. (1987)

reported that the germination percentage (pre-harvest sprouting) was scored 105-140 days

after sowing in 15 bunch varieties of 105 days duration. TG-9, TG-17 and TG-15

showed the lowest germination percentage (8-10 % after 140 days), followed by CGS-1-

19 and Dh-8. Reddy et al. (1987) observed that CGC-7, also known as CGS-1-19

possesses a seed dormancy period of 5 weeks. The F8 of CGC-7 shows differential

germination, indicating variation for dormancy period.

Kumar et al. (1991) reported that the cultivars of subsp fastigiata generally lacked

dormancy while those of subsp hypogea were characterized by long dormancy periods.

Varman and Raveendran (1991) observed that varieties of bunch groundnut Arachis

hypogaea subsp. Fastigiata, show little seed dormancy, with a result that 20-50 per cent

of pods germinate in situ due to rains at the pod maturity stage. With a view of

identifying seed dormancy, some 55 high yielding genotypes of subsp. Fastigiata were

grown in the field during kharif 1988 at the agricultural research Station, Aliyarnagar.

Pods were collected at maturity and evaluated for seed dormancy. ICGV-86011

possessed seed dormancy, with pods sprouting 18 days after harvest compared with 2-4

days for the other genotypes. Seed dormancy was also observed in pods of ICGV-86011

subjected to water stress at pod maturity. Nautiyal et al. (1993) reported that the degree

of maturity, position of kernel in the pod and the storage period all had a confounding

influence on the seed dormancy.

Anonymous (1995) reported that relationship between dormancy and viability,

fourteen dormant and non-dormant groundnut genotypes were raised during the rabi-

summer 1995 and pods after through drying were placed in cotton bags and stored inside

the galvanized bins. The viability of the seeds was monitored at different storage periods.

Dormant genotypes maintained higher germinability than the non-dormant types. The

germinability of the dormant genotypes viz., ICGS011, ICGS-44, TG-22 was > 99 per

cent even after eight months storage. Venu et al. (1995) studied that the relationship of

seed moisture content with dormancy and seedling vigour in Spanish and Virginia

genotypes of groundnut. It was observed that the whole seed dormancy was higher in

both Spanish and Virginia types as compared to embryo dormancy. The genotype Dh-3-

30 indicated dormancy period of 20-30 days with whole seeds but did not show embryo

dormancy, indicating the presence of dormancy factors in seed coat. On the contrary, the

removal of seed coat in ICGS-30, EDR, Bidar local and Mardur local improved the

germination but failed to release the dormancy completely, thereby indicating that the

factors responsible for dormancy might be residing both in seed coat and embryo. The

embryo of Dh-3-30 which had no dormancy exhibited higher seedling vigour index

values than the whole seeds of the same genotype as well as whole seeds and embryo’s of

the other dormant genotypes.

Nautiyal et al. (1996) screened about 200 Spanish germplasm lines for fresh seed

dormancy during rabi/summer 1995. Revealed that genotypes showed variation in

germination percentage. During rabi/summer 1995, the crop was harvested at 110 DAS

and most of the genotypes showed more than 60 per cent fresh seed dormancy, finally

they concluded that the dormancy period of most of the genotypes was laid between 30-

40 days. Anonymous (1999) reported that three mutants of cv. Girnar-1 (non-dormant)

namely PBS-30021, 30109 and 30163 were found to possess fresh seed dormancy about

1-4 weeks. Joshi and Nautiyal (1999) conducted an experiment at NRC, Junagarh

(Gujarat) on groundnut to screen about 180 Spanish type germplasm accessions

alongwith the cultivars having fresh seed dormancy viz., ICGS-11 and ICGS-44 as

checks, were screened both under field and laboratory conditions. They reported that the

genotypes NRCG-7197, NRCG-7186 and NRCG-835 had 23, 24 and 28 per cent pods

were sprouted, respectively in the field. They concluded that these genotypes had 8, 1

and 5 per cent fresh seed dormancy.

Upadhyay and Nigam (1999) conducted an experiment to determine the fresh

seed dormancy index (FSDI) percentage in 200 groundnut germplasm accessions and 21

cultivars belonging to the Spanish group and revealed that, large variation in pod loss due

to in situ sprouting of seed, the fresh seed dormancy was found among the accessions and

cultivars. Fresh seed dormancy index varied from 2 per cent in chico to 88 per cent in

ICGS-44 (check), concluded that cultivars with an FSDI value of less than 10 per cent,

showed more pod loss in situ than the cultivars with high FSDI. Thus, pod loss due to in

situ sprouting increased with a decrease in FSDI. Cultivar SB-XI did not show any in

situ sprouting or pod loss. Mathur et al. (2000) stated that two cultivars of groundnut viz.,

PBS-12115 and PBS-12126 were found to be higher yielder and PBS-12115 possessed

fresh seed dormancy of 21-28 days, while PBS-12126 possessed fresh seed dormancy of

about 14-21 days and suggested to use these two genotypes as donar parents for

incorporation of fresh seed dormancy in breeding programme. Swain et al. (2001) studied

17 erect, 8 semi-spreading and 5 spreading varieties to analyse the nature of variation of

seed dormancy in different varietal forms of groundnut and revealed that dormancy

period of the varieties ranged from 33 to 107 days. Most erect varieties showed short to

moderate dormancy period and most semi-spreading and spreading varieties possessed

longer dormancy period coupled with strong intensity of dormancy and seeds of kharif

showed the highest degree of dormancy followed by rabi and summer. Finally they stated

that TG-26 had the longest dormancy period of 107 days.

Swain and Sahoo (2001) studied the duration of seed dormancy in different bunch

type groundnut cultivars and reported wide variation in their duration ranging from 5.4

days to 106.6 days. Manonmani (2002) studied both dormant and non-dormant cultivars

of groundnut, reported that dormant cultivars maintained higher seed germinability in

storage for a longer period than the non-dormant cultivar of groundnut varieties. Singh et

al. (2002) screened 5 different cultivars of groundnut for detection of dormancy periods,

revealed that all the cultivars possess dormancy period ranging from 4 to 5 months.

Minimum dormancy of 4 months was observed in non-dormant bunch type groundnut

cultivars viz., Chitra, Prakash and Kaushal whereas in spreading type groundnut cultivars

viz., Chandra and Amber possessed 5 months dormancy period. The results indicated that

bunch type varieties had less dormancy in comparison to spreading type of cultivars.

Asibuo James Yaw et al. (2008) conducted an experiment at Ghana (Africa) to

determine the heritability of fresh seed dormancy in groundnut and to transfer this trait

from dormant exotic lines (ICGV-86158 and ICGV-87388) into two non-dormant

groundnut varieties (Shitaochi and Aprewa), they reported that seed dormancy is

controlled by monogenic inheritance with dormancy dominant over non-dormant, as the

results showed that more than 90 per cent of the freshly harvested seeds of the non-

dormant parents germinated before 14 days, whereas less than 10 per cent of the seeds of

the dormant parents germinated during the same period.

###############

Add abstract and introduction properly suitable to review article.

Delete the references from literature cited, if it is not appeared in text.

Submit the said article to any journal who is publishing the review article.

What is about first article? Try to submit / publish at an earliest possible.

**************

REFERENCES:

Abdul Baki, A.A. and Anderson, J.D. 1973. Crop Sci. 13 : 630-633.

Abdul-Rahman and Issenberg, F.M.R. 1974 J. agric. Sci. Comb, U.K. 82 : 113-116.

Abrar, A.K. and Jadhav, B.B. 1991. Ann. Pl. Physiol. 5 (1) : 64-69.

Agarwal, R.L. 1995. Seed Technology (2nd Edn.). Oxford and IBH Pub.Co., New Delhi : 583-590.

Amen, R.D. 1968. Bot. Rev. 34 : 1-31.

Anonymous. 1979. AICRP on Oil Seeds, 12th Annual Workshop (Kharif). pp. 19.

Anonymous. 1995. Annual Report, NRC for Groundnut, Junagarh-362 001, Gujarat, India.

Anonymous. 1999. Annual Report 1998-99. NRC for Groundnut, Junagarh-362 001, Gujarat, India. pp. 35.

Anonymous. 1999. Seed Sci. and Technol. 13 (2) : 299-513.

Anonymous. 2007. Agriculture Research Data Book, Indian Council of Agriculture Research, Krishi Bhavan, New Delhi – 110 001, India. pp. 215-216.

Anonymous. 2007a. Economics Survey of Maharashtra, Directorate of Economics, Planning Department, Govt. of Maharashtra, Mumbai, India. pp. 197-198.

Appalanaidu, B. and K.S. Murthy. 1961 The Andra Agric. J. 8 : 168-175.

Ashok Kumar, T.S. 1989. M.Sc. (Agri.) thesis, Univ. Agric. Sci., Dharwad, pp. 1-188.

Asibuo James Yaw, Akromah Richard, Safokantanka, Osei, Adu-Dapaah, Hanskofi Obemeng-Dapaah Seth and Agyeman Adelaide. 2008. African J. Biotechnol. 7 (4) : 421-424.

*Bailey, W.K. and John, E. Bear. 1972. J. American Peanut Res. And Edu. Assoc. 5 (1) : 40-47.

Bewley, J.D. and Black, M. 1982. Physiology and biochemistry of seeds. II.. Springer-Verlag Berlin Heidelberg, New York. pp. 88-101.

Bhapkar, D.G., Patil, P.S. and Patil, V.A. 1986. J. Maharashtra agric.Univ. 11 (1) : 68-71.

*Cleland, R. 1963. Nature. 200 : 908.

El-Maghraby, O.M.O. & Mohammed, El-Maraghy. 2007.Mycopathologia.98(3):165-170.

Gavrielith, G.H. 1962. Proc. Int. Seed Test. Assoc. 27 : 357-372.

Gulek, J.A., Clark, L.E. and Smith, O.D. 1977. Crop Sci. 17 : 777-782.

Gupta, R.K., Singh, S.S. and Verma, M.M. 1985. Indian J. agric. Res. 19 (2) : 82-86.

Hansen, C.M. 1949. Agricultural Engineering. 30 : 377-378.

http://www.icrisat.org/text/cool stuff/crops / g crops 4.html. groundnut, L’ arachide

Hull, F.H. 1937. Fla. Arg. Exp. Station Tech. Bull. pp. 314.

Jackson, M.C. 1967. Soil chemical analysis, Prentice Hall of India Pvt. Ltd., New Delhi. pp. 498.

Jagatap, P.B. 2000. M.Sc. (Agri.) thesis, PGI, MPKV, Rahuri. pp. 1-85.

Javeed, M.S., Abdul-Wahid, S., Idrees, M. and Salem, A. 1998. Pakistan J. Phytopath. 10 (1) : 53-55.

John, C.M., Seshadri, C.R. and Rao, M.B.S. 1950. Madras agric. J. 35 : 159-167.

Joshi, Y.C. and Nautiyal, P.C. 1999 Research Accomplishments, Deptt. of Plant Physiology : 54-62.

Kamala, T., Sadasivan, R. and Rathnam, N.N. 1987. Madras agric. J. (1987). 74 (2) : 114-115.

Karivaratha Raju, T.V. and Rao, J.S. 1972. Madras Agricultural Journal. 59 : 257-261.

Karivartharaju, T.V. and Rao, J.S. 1972 Madras agric. J. 59 : 257-261.

Ketering, D.L. and Morgan, P.W. 1969. Pl. Physiol. 44 : 326-330.

Ketring, D.L. 1977. Agron. J. 69 : 110-114.

*Khan, A.A. 1977. The Physiology and biochemical of seed germination. North-Holland Pub. Co. Amersterdom. pp. 26.

Kramer, P.J. and Kozlowski, T.T. 1960. Physiology of trees. McGraw Hill, New York.

Krishnamurthy, K. 1969. Indian Journal of Agricultural Sciences. 37 : 33-36.

Kumar, T.S.A., Gowda, M.V.C. and Nadaf, H.L. 1991. J. Oil Seeds Res. (1991), 8 (2) : 166-172.

Lakon, G. 1949. Plant Physiol. 24 : 389-393.

Leopold, A.C. 1964. Maleic hydrazide as an antiauxin in plants. Pl. Sci. 114 : 9.

Lin, H. and Lin, C.Y. 1971a. J. Taiwan Agric. Res. 20 : 42-48.

Lin, H. and Lin, C.Y. 1971b. J. Taiwan agric. Res. 20 : 49-53.

Loeffler, T.M., D.M. Tekromy and D.B. Egli. 1988. Journal of Seed Tech. 12 (1) : 37-53.

Manon Mani. 2002. Seed Res. 30 (1) : 158-160.

Mathur, R.K., Manivel, P., Samdur, M.Y. and Bandopadhyay, A. 2000. J. Oilseeds Res. 17 (1) : 181-182.

Matthews, S. 1976. Seed in relation to ecology in Advances in research and technology of seeds (Thompson, J. Red.) part II. Centre for Agricultural Publishing and Documentation, Wageningen. pp. 92.

Mikkelsen, D.S., Griffeth, R.B. and Pririe, D. 1952. Agronomy Journal. 44 : 533-536.

Nagarjun, P. and G.D. Radder. 1983. Seed Res. 11 (1) : 24.

Nagarjun, P., G.D. Radder and V.S. Patil. 1980. Seed Res. 8 (2) : 121-126.

Nagarjun, S.S. and Gopalkrishnan, S. 1957 Madras agric. J. 44 : 672.

Nagarjun, S.S. and Gopalkrishnan, S. 1958. Curr. Sci. 27 : 29-30.

Narasimhareddy, S.B. and Swamy, P.M. 1979. J. Expt. Bot. 30 : 37-42.

Nautiyal, P.C. 2004. Groundnut Research in India : 321-338.

Nautiyal, P.C., Bandyopadhyay, A. and Ravindra, V. 1993. J. Oilseed Res. 10 : 271-276.

Nautiyal, P.C., Ravindra, V. and Misra, J.B. 1996. Research accomplishments, Deptt. of Plant Physiology, NRC on groundnut, Junagarh (Gj), India : 63-69.

Naylor, A.W. and Davis, E.A. 1950. Bot. Gaz. 112 : 112-126.

Pandey, S.N. and Sinha, B.K. 2006a. Plant growth regulators. Plant Physiology. 4 th Edn. Vikas Publishing Pvt. Ltd., New Delhi: 446-484.

Pandey, S.N. and Sinha, B.K. 2006b. Biology of dormancy, Plant Physiology. 4th Edn. Vikas Publishing Pvt. Ltd., New Delhi: 531-537.

Pandya, R.B. and Patel, V.J. 1986. J. Oilseed Res. 3 (1) : 19-27.

Paterson, D.R., Wittwer, S.H., Willer, L.F. and Sell, H.M. 1952.Pl. Physiol. 27 : 135-142.

Patil, S.H. 1973. Indian J. Agric. Sci. 43 : 370-376.

Patil, S.H. and Chandramouli. 1978. Indian J. Agric. Sci. 48 : 351-358.

Patil, V.K., Quadar, M.A. and Shinde, V.S. 1991. Agric. Situation India. 46 : 401-407.

Ramachandran, M., Loganatham, N.S., Sridharan, C.S., Chandrasekheram, N.R. and Krishnaswami, P. 1967. Indian J. agric. Sci. 37 : 429-436.

Randhawa, K.S. and Nandpuri, K.S. 1966 Indian Journal of Agronomy. 11 : 238-242.

Rao, N.G. 1976. Paper presented at the Workshop cum Seminar of All India Coordinated Research Project on Oilsseds (Kharif crops). pp. 1-51.

*Rao, S.N. and Wittwer, S.H. 1955. Amer. Petste. J. 32 : 51-59.

Rasheed, S., Dawar, S., Ghaffer, A. and Shaukat, S.S. 2004. Pakistan J. Botany. 36 (1) : 199-202.

Reddy, P.S., Basu, M.S., Tiwari, S.P., Devidayal and Radhakrishnan, T. 1987. Curr. Sci. India. 56 (8) : 368-369.

Reddy, P.S., Zade, V.R. and Deshmukh, S.N. 1985. J. Oilseeds Res. 2 :103-106.

Roberts, E.H. and Roberts, D.L. 1972. In viability of seeds (Roberts, E.H. Ed.), Chapman and Hall Ltd., 11 New Fetter Lane, London EC-4. pp. 424-429.

Schoene, D.C. and Hoffman, O.L. 1949. Science, 109 : 588-589.

Singh, C.B., Verma, R.K., Khan, A.A., Singh, N.B. and Uttam, A.K. 2002. Seed Res. 30 (2) : 211-214.

Snedecor, G.W. and Cochran, W.G. 1967. Statistical methods chapter 12.

Sreeramulu, N. and Rao, I.M. 1971. Aust. J. Bot. 19 : 273-280.

Suryanarayana, N., G.H. Sankara Reddy and T. Bapi Reddy. 1976. Oilseeds J. 6 : 54-58.

Swain, S.K., Sahoo, P. and Patnaik, M.C. 2001. Seed Res. 29 (1) : 13-17.

Swain, S.K. and P. Sahoo. 2001. J. Res., Orisa Univ. Agric. Tech. 19 (1,2) : 40-44.

Swain, S.K., Sahoo, P. and Patnaik, M.C. 2002. J. Oilseeds Res. 19 (2) : 223-225.

Tai, Y.P. and Young, C.T. 1974. Crop Sci. 14 : 227-229.

Toole, V.K., Bailey, W.K. and Toole, E.H. 1964 Pl. Physiol. 39 : 822-855.

Upadhyay, H.D. and Nigam, S.N. 1999. Crop Science.

Vaithialingam, R. and Rao, J.S. 1973a Madras agric. J. 1973. 6 (9-12) : 1862-1863.

Vaithialingam, R. and Rao, J.S. 1973b. Madras agric. J. 60 (9-12) : 1864-1865.

Varisai, M.S. and M.S. Dorairaj. 1968 Indian J. agric. Sci. 28 (1) : 73-75.

Varman, P.V. and Raveendran, T.S. 1991. Curr. Res. University of Agricultural Sciences, Bangalore. 20 (11) : 237-238.

*Vavilov, N.I. 1951. Chronica Botanica. 13 (1/6) : 1949-1950.

Venu, P., Chetti, M.B., Uppar, D.S., Doddamani, M.B. and Mummigatti, U.V. 1995. J. Oilseeds Res. 12 (1) : 103-108.

Weiss, E.A. 1983. Groundnut in : Oilseed Crops. Longmann Group Ltd., London. pp.111.

Wittwer, S.H. and Hansen, C.M. 1951. Agronomy Journal. 43 : 340-341.

Wittwer, S.H. and Paterson, D.R. 1952. Quarterly Bulletin, Michigan Agricultural Experiment Station. 34 : 3-8.

Zukel, J.W. 1950. Agric. Chem. 5 : 35-36.

*Original not seen.