effect of hydro and osmo priming on quality of chickpea (cicer arietinum l.) seeds

Effect of hydro and Osmo priming on quality of Chickpea (Cicer arietinum L.) Seeds

IJPBCS


Abebe Sori Researcher at Fitche Soil Research Center, Oromia Agricultural Research Institutes, Addis Ababa, Ethiopia. Email: abebesori@ gmail.com; Tel: +25111111351209

Laboratory and lath-house experiment were carried out at National Seed Quality Control Laboratory Center, and at Debre Zeit Agricultural Research Center lath-house, Ethiopia, respectively with the objectives to determine the effectiveness of seed priming and variety on seed quality and stand establishment. Experimental factors were three priming media [H2O, 0.5% KH2PO4, unprimed)] and six Chickpea varieties (DZ-10-4, Arerti, Habru, DZ-10-11, Akaki and Natoli) arranged in CRD with four replications. The laboratory results revealed significant differences (p<0.01) for all parameters except vigor index II, which was significant at (p<0.05) among different priming treatments and variety in seed germination, all seed vigor tests. The interactions of the main effect were significant (p<0.01) for all quality parameters excluding vigor index II, seedling shoot and root length and seedling dry weight. Significant correlations were also observed between emergence index and most of the vigor parameters. Moreover, water priming enhanced the germination and vigor index I of all varieties except DZ-10-4 and Habru; speed of germination of Arerti and electrical conductivity of all varieties tested. Hydropriming decreased electrical conductivity of seeds by 20% as compared to osmopriming. Therefore, it can be concluded that hydro priming can step-up economical benefit of chickpea growing farmers.

Key words: Chickpea, emergence index, hydropriming, osmopriming, seed quality, vigor index INTRODUCTION Chickpea (Cicer arietinum L.) is 98-99% self pollinated (Singh, 1987); diploid species having basic chromosome number of 16 and belongs to family Leguminasae (Poehlman and Sleper, 1995). It is cultivated over a vast geographical range, from South-East Asia, across the Indian subcontinent, the Near East, Southern Europe, the Balkans, the Mediterranean basin to East Africa (Abbo et al., 2000).It is one of the cool season food legume crops of Ethiopia which is mainly grown in the central, Northern and Eastern high land area of the country where the mean annual rainfall and altitude, respectively range from 700-2000mm and 1400-2300 m.a.s.l. (Geletu, 1994). Two types of chickpea namely Desi and Kabuli are grown in Ethiopia at the same time as unimproved local

Desi variety being to the most widely grown in all places. Among improved varieties currently grown in Ethiopia , DZ 10-4, DZ 10-11, and Dubie were developed from local breeding materials whilst Mariye, Worku, Akaki, Shasho, Chafe, Arerti and Habru were developed using breeding materials improved from abroad (Muehlbauer and Abebe,1997). In Ethiopia, Chickpea seed can be eaten as green vegetable (eshet), roasted (kollo), boiled (nifro) and dry vegetable. The flour of chickpea is also used to make „shimbra asa’, popular dish during fasting time. Flour of roasted chickpea seeds (shiro) are used to make shiro wot (sauce) and taken with injera (bread). Chickpea can also improve the soil fertility through biological

International Journal of Plant Breeding and Crop Science Vol. 1(2), pp. 028-037, November, 2014. © www.premierpublishers.org. ISSN: 2167-0449

Research Article

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Table1. Description of chickpea varieties used for the study.

SN Chickpea varieties Year of release Seed color Type/category

1 DZ-10-4 1974 White Kabuli

2 Arerti 1999 White Kabuli 3 Habru 2004 White Kabuli 4 DZ-10-11 1974 Light Brown Desi 5 Akaki 1995 Golden Desi 6 Natoli 2007 Light Golden Desi

Source: (MoAD, 2008; Menale et al., 2009).

nitrogen fixation and intercropped with cereals. Despite this fact, however, the yield of chickpea in Ethiopia is still low which can be attributed to biotic and abiotic factors (Geletu and Yadeta, 2002). Constraints to good establishment are also including low quality seed in addition to lack of soil moisture (Gurumu and Naylor, 1991).These conditions result in poor emergence that may subsequently cause sparse plant stands (Saxena et al., 1997). Despite chickpea plant can produce extra vegetative growth (in a favorable moisture regime) to cover available space, poor plant stands and stunted growth are often a major cause of low seed yields in semiarid environments (Saxena, 1987). One way of improving productivity of chickpea in drought prone area is seed priming. The seed priming process simply involves soaking the seed overnight (for about 8 hrs), surface drying them and sowing within the same day (Musa et al., 2001) to hasten germination, enhances crop establishment and promotes seedling vigor (Harris et al., 1999). It includes soaking seed in water or osmotic solution, and intermixture with porous matrix material (Ghana and William, 2003). Humidification is also method of seed enhancement when seeds are hydrated at a high relative humidity (Van Pijlen et al., 1996). On-farm priming of seeds of a range of tropical and sub-tropical crops have been tested as a means to promote rapid germination and emergence and to increase seedling vigor and hence yield (Harris, 2004). Therefore, the present study was initiated with the objectives to determine the effectiveness of seed priming treatment and variety on seed quality and stand establishment of chickpea varieties. MATERIALS AND METHODS EXPERIMENTAL MATERIALS, TREATMENTS AND DESIGN The experiment was conducted in laboratory and lath-house on six chickpea varieties released at different year (Table1).

The six chickpea varieties produced in the same production year were used for this study. The seed used for the test varieties was obtained from the National Chickpea Improvement Program, Debre Zeit Agricultural Research Center. The varieties were selected based on their production under Ethiopia conditions. LABORATORY AND LATH-HOUSE EXPERIMENTS The experiment was laid out into two factorial arrangement (six chickpea varieties and three priming treatments: water, 0.5% KH2PO4, and control) in complete randomized design (CRD) with four replications. Standard Germination Test (%) In the laboratory 400 chickpea seeds in four replications for every treatment were tested for standard germination by keeping the seeds in germination box filled with moist sand at a temperature of 25

oC. The final count was made on the 8

th days.

At the end of the test, the seedlings were evaluated and clustered into normal, abnormal, and dead seed. The normal seedlings including hard seeds were considered as standard germination and their respective percentages were calculated for all the four replications (ISTA, 2004). Germination %= Number of normal seedlings x100

Number of seeds sown Speed of Germination To determine the rate of germination, which is an expression of vigor, four replicates of 100 seed per replication of the primed and non primed samples were planted and kept at a temperature of 25

oC.

For each replicate, the numbers of germinated seeds were counted daily until there was no further germination to take place. Each day normal seedlings were removed at predetermined size and until the time all the seeds capable to prouce normal seedlings were germinated. An index was calculated by dividing the


Int. J. Plant Breeding Crop Sci. 029 number of normal seedling removed each day by the number of days in which they were removed (Maguire, 1962). Germination index (GI) =Σ (Gt/Dt), summation of mean number of normal seedlings germinated per day for t days. 𝑮𝑰 =𝑵𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒏𝒐𝒓𝒎𝒂𝒍 𝒔𝒆𝒆𝒅𝒍𝒊𝒏𝒈𝒔+⋯+𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒏𝒐𝒓𝒎𝒂𝒍 𝒔𝒆𝒆𝒅𝒍𝒊𝒏𝒈𝒔 𝒂𝒕𝒇𝒊𝒏𝒂𝒍 𝒄𝒐𝒖𝒏𝒕

𝒅𝒂𝒚𝒔 𝒐𝒇 𝒇𝒊𝒓𝒔𝒕 𝒄𝒐𝒖𝒏𝒕 𝒅𝒂𝒚𝒔 𝒐𝒇 𝒇𝒊𝒏𝒂𝒍 𝒄𝒐𝒖𝒏𝒕

Seedling Shoot and Root Length The seedlings shoot and root lengths were measured after the final count in standard germination test. Ten normal seedlings were selected randomly from each replicate. The shoot length was measured from point of the attachment of the cotyledon to the tip of the seedling. Similarly, the root length was measured from the point of attachment to the tip of the root. Average shoot or root length (cm) was computed by dividing the total shoot or root length by total number of normal seedlings measured (Fiala, 1987). Seedling Dry Weight Seedling dry weight was measured in grams after final count in the standard germination test. Ten seedlings selected randomly from each replicate were cut free from their cotyledons and placed in envelopes and dried in an oven at 80±1

oC for 24 hours. The dried

seedlings were weighed to the nearest grams and the average dry weight was calculated. Vigor Index Seedling vigor index I: This was calculated by multiplying the standard germination with the average sum of shoot length (cm) and root length (cm) on the 8

th day of germination (Islam et al., 2009).

Seedling vigor index II: It was calculated by multiplying the standard germination with mean seedling dry weight (Fiala, 1987). In both indices 10 randomly selected seedlings were used. Conductivity Test The experiment was conducted in complete randomized design with four replications. After washing in distilled water, four replicates of 100 seeds each were weighted at 2 decimal place and seeds (primed as well as unprimed) were soaked in 100ml distilled water in a 150ml flask. Flasks were then be stirred and held at 20

oC for 24 hours. Conductivity of leachates was

measured with conductivity meter and the results were expressed in µscm

-1g

-1. The dip cell was rinsed in

distilled water after each measurement. Hard seeds in each sample at the end of the test were examined

following (ISTA, 1999), removed, surface dried and weighted. This weight was subtracted from the initial weight of each replicate of seeds for the variety included in the study for calculation of leachates electrical conductivity (Wang et al., 2004). In addition, one treatment was kept as a control by using unprimed seeds. Conductivity per gram of seed was then calculated. The conductivity of the control was also measured. Emergence Index Emergence index was studied in lath-house on Agricultural soils by taking 400 seeds in four replications of an entry. The counted 100 seeds per replication were sown in every pot. The pots were placed in lath-house to monitor seedling emergence. For each replicate, seedling emergence was counted daily until there was not further germination. The emergence index was worked out as per Wang et al. (2005). The emergence index was correlated with other seed vigor tests for all entries. Emergence index =Σ (Et/Dt), summation of mean number of emerged seeds per day for t days. Data Analysis The collected data were subjected to statistical analysis as per the design using Statistical Analysis System (SAS, 2001) computer software. Where significant differences were detected, the mean separations were carried out using the least significant differences (LSD) at 0.05 level of probability. Linear correlations between emergence index and other seed vigor tests were calculated using SAS computer software. RESULTS AND DISCUSSION LABORATORY AND LATH-HOUSE EXPERIMENTS Analysis of variance revealed that seed invigoration technique had influenced seed quality significantly. The effects of priming treatments on percentage of standard germination, speed of germination, electrical conductivity, seedling vigor index II, emergence index, shoot length, root length , seedling dry weight and seedling vigor index I were significantly different. In addition, all these parameters showed significant differences over varieties at p<0.01.There were also significant differences in the interaction of priming treatment and variety for all parameters (p<0.01).

Standard Germination (%) Significant differences among varieties were obtained for standard germination percentage across the priming treatments. Comparing the varieties, the lowest and the

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Table 2. Interaction Effect of Priming Medium By Chickpea Variety on Standard Germination (%)

Priming media

Varieties Control Water KH2PO4 (0.5%) Mean

DZ-10-4 84i 80

j 69

k 78

e

Arerti 96bcd

100a 99

ab 98

a

Habru 94def

88h 82

gij 88

d

DZ-10-11 91gf 98

abc 90

hg 93

b

Akaki 91gf 95

cde 91

gf 92

bc

Natoli 89hg

93ef 90

hg 91

c

Mean 91a 92

a 87

b 90

Variety Priming Variety x priming

LSD(5%) 1.87 1.32 3.24

CV(%) 2.54 Means with the same letters are not significantly different from each other at p<0.05.

highest germination percentage under laboratory condition were recorded for DZ-10-4 (78) and Arerti (98) respectively. However, germination percentage of DZ-10-11 and Akaki as well as that of Natoli and Akaki were not significantly different from each other. Differences in the response of the varieties to priming media also had been reported by other workers. Nascimento (2003) forwarded that differences in the response of seeds to priming has been found to be dependent on the osmotica (priming), duration of priming, seed maturity, variety, and environmental conditions. Higher germination percentage was found for water treatment though it was behaved similar with that of the control. Whereas the application of phosphorous at p 0.5% from the source solution of KH2PO4 through seed priming could not show better result as compared to water priming . The present results are in accordance with the observations of Umair et al. (2010) who reported that osmopriming like PEG-6000 was found to reduce germination percentage of mungbean. There was highly significant difference between variety by priming treatment interaction for the standard germination at p<0.01, providing evidence that priming treatments affected germination percentage of chickpea varieties differently (Table 2). In general, effectively higher percentages of standard germination were recorded for all varieties by soaking the seeds in water except DZ-10-4 and Habru. In addition, significantly lower germination percentages were obtained from all the varieties that were treated with osmo priming as compared to water priming except Arerti. In the contrast, DZ-10-11, Akaki and Natoli that were osmoprimed had similar results for standard germination as compared to the control. The

seeds primed with water effectively improved the germination percentage of all varieties other than DZ-10-4 and Habru. This is supported by observations of Harris et al. (1999) who reported that under normal conditions, hydro-priming is effective for germination and later growth of chickpea. Nascimento (2005) also reported that primed seeds had higher germination percentage compared to unprimed seeds. Moreover, Umair et al. (2010) found that hydro priming significantly improved final germination percentage of chickpea. The same author also reported that osmopriming using P at 0.6% applied in the form of KH2PO4 significantly improved final germination percentage. Speed of Germination A statistically significant difference of treatments and interaction were found among the varieties for speed of germination at p<0.01(Table 3).Speed of germination was affected by the varieties in which significantly different responses were obtained between Arerti and the other varieties except DZ-10-11. Habru and Akaki were also significantly different from the remaining varieties but not from each other. The least speed of germination was recorded by Natoli where as the maximum speed of germination were obtained from statistically similar Arerti and DZ-10-11. Looking in to the effect of priming treatments on speed of germination, water treatment was effectively increased the speed of germination over the control and the osmopriming. However, osmopriming was not significantly effective in increasing the speed of germination over the control. The variety x priming treatment interactions on the speed of germination was significant at p<0.01(Table 3). Trend of speed of germination in different varieties


Int. J. Plant Breeding Crop Sci. 031

Table 3. Interaction Effect of Priming Medium By Chickpea Variety on The Speed of Germination

Priming media


DZ-10-4 23.03cdef

24.09c 20.00

gh 22.37

b

Arerti 23.47cd

27.84a 24.65

bc 25.32

a

Habru 20.84fg 21.07

efg 18.92

ghi 20.27

c

DZ-10-11 23.26cde

24.61bc

26.86ab

24.91a

Akaki 21.20defg

19.96gh

19.20ghi

20.10c

Natoli 16.09j 17.99

hij 16.93

ij 17.00

d

Mean 21.32b 22.59

a 21.09

b 21.66


LSD (5%) 1.38 0.98 2.39

CV (%) 7.78

Means with the same letter are not significantly different from each other and means not sharing the same letters are different

significantly at p<0.05.

revealed that the greatest speed of germination in Arerti occurred when the seeds primed with water, while DZ-10-11 primed with 0.5% KH2PO4 caused the highest speed of germination compared to the control despite it was at par with water priming .Water treated seeds showed increased speed of germination as compared to unprimed seeds for all varieties except for Akaki. However, only Arerti demonstrated significant improvement in the speed of germination when the seeds were primed in water. Germination rate of Habru with Akaki as well as Natoli with Akaki showed similar statistical scenario due to hydro priming. On the other hand, all the varieties found to show lesser speed of germination while, significant reduction in the speed of germination was observed in DZ-10-4 only when the seeds were osmoprimed. Improvement in the speed of germination of seeds of chickpea varieties subject to hydro priming is in conformity with result reported by Mohamadi (2009), who observed a significant improvement in the germination rate of soybean seeds due to hydro priming over unprimed one and Ghassemi-Golezani et al. (2008) reported that germination rate was increased significantly from 0.34 in unprimed seeds to 0.52 in hydro primed chickpea seeds. In addition, increased in germination rate of primed seeds over unprimed seeds is also in accordance with the findings of Afzal et al. (2005). Bove et al. (2001) reported that faster germination is associated with earlier activation of metabolism and preparation of the embryo axis for elongation during the germination process. Priming also causes to reduce the

adherence of seed coat due to imbibitions, which may permit to emerge out radical without resistance (Nascimento and West, 1998). So this may also contribute for an increase in the rate of germination due to pre sowing seed treatment as indicated in (Table 3). Seedling Vigor Index I When the varieties averaged across the priming treatments, larger seedling vigor index I was recorded for variety Arerti (2657.9) as compared to the other varieties that were used for tests despite it was showed similar effect with that of DZ-10-4, DZ-10-11 and Akaki. Natoli and Habru were also significantly different from the remaining varieties but not from each other. Variety Habru (1997.3) having lesser seedling vigor index I was at par with Natoli (2042.1) (Table 4). Seedling vigor index I of the 8 days old seedlings were significantly differing among priming media/treatments at P < 0.01 (Table 4).The priming medium water had produced the highest seedling vigor index over the varieties followed by 0.5% KH2PO4.The minimum seedling vigor index I was in control where non-primed seeds were used. Water priming increased seedling vigor index I by 14% and 5% respectively as compared to the control and osmopriming. Moreover, osmopriming also improved seedling vigor index I by 9% over the control. Water and 0.5% KH2PO4treatments exhibited more vigor index I over the control. At the same time, these treatments improved shoot length and root length (Figures 2 and 3). This parameter depends on germination percentage, shoot

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Table 4 .Interaction Effect of Priming Medium By Variety on The Vigor Index I

Priming media


DZ-10-4 2683.7a 2744.3

a 2400.8

c 2609.60

a

Arerti 2438.0bc

2731.4a 2809.70

a 2659.70

a

Habru 1871.3g 2125.5

def 1995.2f

g 1997.33

b

DZ-10-11 2240.4cde

2851.1a 2735.0

a 2608.83

a

Akaki 2354.8cd

2793.8a 2652.5

ab 2600.37

a

Natoli 1910.7gf 2122.5

def 2093.0

gef 2042.07

b

Mean 2249.82c 2561.43

a 2447.70

b 2419.65


LSD (5%) 137.05 96.91 237.38

CV(%) 6.67 Means with the same letter are not significantly different from each other and means not sharing the same letters are different significantly at p<0.05.

length and root length. However, in the current investigation enhancements of vigor index contributed by shoot and root length because these treatments didn‟t improved germination percentage effectively over the control. Results of the present study suggested that seed priming was effective tools for seed invigoration in chickpea. This is supported by Thakare et al. (2011) observed that oxygenated peptone chickpea seed treatment exhibited more vigor index I. This finding also was endorsed with Umair et al (2010) who reported that both hydro priming and osmo priming 0.6% KH2PO4

improved vigor Index I of mungbean (Vigna radiata L.). He also concluded that the application of P in the form of seed treatment resulted in increased seedling vigor. The increased vigor of P-enriched seed might be due to increased P content both inside the seeds and on the seed surfaces which leads to better establishment of seedlings (Ros et al., 1997).The reduction in the seedling vigor has also been reported by (Basra et al., 2003). There was significant difference in variety x priming medium interaction for seedling vigor index I at p< 0.01.When the seeds were water treated, all the varieties performed effectively for seedling vigor index I over the control except DZ-10-4 and Natoli. But water priming couldn‟t significantly improve seedling vigor Index I of DZ-10-4 and Natoli over the control. When the seeds were primed with the solution of 0.5%KH2PO4 all varieties showed improvement for seedling vigor index I over the control except DZ-10-4 that had the least vigor index I at osmopriming. However, statistically significant increase in seedling vigor index was revealed by Arerti, DZ-10-11 and Akaki as compared to the control (Table 4). Still the seedling vigor index I of osmopriming and unprimed were the same for the varieties Habru and Natoli. On the other hand, both hydro priming and osmopriming were not

effectively improved the seedling vigor. Index I of DZ-10-4 and Natoli varieties as compared to the control. Comparing hydro priming with that of KH2PO4 (0.5%), other than DZ-10-4 all the varieties had similar seedling vigor index I for the two priming media (Table 4). Seedling Vigor Index II The mean values for seedling vigor index II that indicate the main effect of variety and priming treatment are presented in Figure 1. The analysis of variance revealed significant differences in seedling vigor index II due to variety effect (p<0.01) and due to priming treatment effect (p<0.05) but there was no significant difference for variety x priming treatment interaction. Looking at the effects of varieties on the seedling vigor ndex II, they responded differently to the priming treatments for seedling vigor index II (Figure1A).Natoli had the highest seedling vigor index II and then followed by Arerti. However, the lowest seedling vigor index II was produced by DZ-10-11 but it was at par with DZ-10-4.Furthermore, there was similar seedling vigor index II between Akaki and Habru varieties statistically. Regarding the effect of priming treatments on seedling vigor index II, priming treatment KH2PO4 (0.5%) was the most effective treatment in increasing the seedling vigor index II over the control where priming treatment of water also gave values significantly different from that of the control. Priming treatment 0.5% KH2PO4 and Water treatment resulted in21% and 15% increase in seedling vigor index II, respectively as compared to the control despite there was no significant difference between water priming and Osmopriming (Figure 1B). Therefore, invigoration made by osmopriming on seedling vigor index II was better than water priming as far as it improved vigor index II by 5% over the hydro


Figure 1. Effect of varieties on seedling vigor index II(A) and Effect of priming medium on seedling vigor index II(B) Bar graphs designated by the same letters are not significantly different from each other at p<0.05

priming despite they were at par. At the same time, osmo priming and hydro priming treatments exhibited more seedling dry weight over the control (Figure1B). This parameter is depends on germination percentage and seedling dry weight. However, the data indicating that for the present study it was the seedling dry weight that brought most enhancement in the vigor index II because germination percentage was not improved by the osmopriming including water priming that was at par with control. This is in close agreement with Dornbos‟s work (2002) who concluded that seedling dry weight represents a logical and relevant estimate of seed vigor. What is more, seedling dry weight was affected by shoots and root length of the seedling, so increased shoots and root length due to water and osmopriming in turn could enhance vigor index II. Electrical Conductivity Test A highly significant difference (P < 0.01) in electrical conductivity reading was observed among the varieties tested as a result of seed treatments (Table 5). The data indicated that primed chickpea seeds with water and 0.5% KH2PO4hadthepotential to reduce seed leachates in all chickpea varieties. Variety Arerti was significantly recorded the lowest electrical conductivity whereas Natoli demonstrated the highest electrical conductivity reading compared to other varieties but it had no significant difference from that of variety DZ-10-4. Next to Natoli and DZ-10-4, higher electrical conductivity was produced by Akaki. Statistically, Habru and DZ-10-11 had also alike electrical conductivity. The

variations amongst varieties in their response to priming might be related to genetic differences. Statistically significant differences in the electrical conductivity readings were also noted for the different priming media (P < 0.01) (Table 5). Electrical conductivity decreased with both hydro and osmo priming treatments as compared to the control, and even more effectively decreased with hydro priming treatment. When averaged across the priming media, electrical conductivity decreased by 31% with water treatment and 14% with osmopriming as compared to unprimed. This means leachates from the seeds decreased by 31% and 14% as a result of water and 0.5% KH2PO4 priming respectively as compared to the control. Moreover, the seeds primed in water decreased electrical conductivity by 20% as compared to that of osmo primed seeds (Table 5). Priming treatment by variety interaction was highly significant for the electrical conductivity at p<0.01. When seeds primed with water, all varieties exhibited a decrease in electrical conductivity over the control and the degree of reduction in the seed electrical conductivity was the highest (54%) for variety Arerti and the lowest (9%) for variety Natoli, whereas there was an intermediate decline for the other varieties that could range from 16% to 44%(Table 5). On the contrary, as comparing to hydro priming with 0 .5% KH2PO4 solution, all the varieties displayed an increment in the electrical conductivity other thanDZ-10-1.When seeds were primed with solution of 0.5 % KH2PO4; all the varieties demonstrated significantly reduction in the

Table 5. Interaction Effect of Priming Medium By Variety on The Electrical Conductivity (µscm-1

g-1

).

Varieties Priming media Mean

Control Water KH2PO4 (0.5%)

DZ-10-4 115.86a 64.70

e 90.86

c 90.47

a

Arerti 58.79ef 27.28

h 43.79

g 43.29

d

Habru 59.70ef 42.84

g 54.61

f 52.38

c

DZ-10-11 65.10e 54.77

f 46.24

g 55.37

c

Akaki 89.45c 60.94

ef 74.17

d 74.85

b

Natoli 88.95c 80.55

d 102.43

b 90.64

a

Mean 79.64a 55.18

c 68.68

b 63.27

Variety Priming Variety x Priming

LSD(5%) 4.04 2.85 6.99

CV(%) 7.27

Means sharing the same letters are at par and those sharing different letters are differed significantly at p<0.05.

electrical conductivity as compared to the control but Habru and Natoli. However, increases in electrical conductivity in Natoli occurred when the seeds primed with 0.5% KH2PO4 solution while in Habru similar result appeared as compared to dry seeds. Prediction of seedling performance in relation to electrical conductivity test is based on nutrient leaching from damaged seeds (McDonald, 1975). Loss of membrane integrity is a key physiological symptom of seed damage and it is measured by the conductivity of seed leachates (Karta, 2009).Kausar et al. (2009) reported that seed priming presumably allowed some repairs of damage to membrane caused by deterioration. Therefore, seed that may deteriorate during maturation and/or storage and thus undergo repair of damaged parts during imbibitions (Copeland and McDonald, 1995) indicates that seeds could benefit more from priming treatments. The lower electrical conductivity of seed leachates treated seeds may be due to beneficial effect of priming in strengthening the cell membrane integrity and permeability (Kurdikeri, 1991). On the other hand, the decrease in leachates as a result of priming treatment has been suggested to come from membrane repair mechanisms that occur during soaking (Steiner, 1990). Seedling Shoot and Root Length, and Seedling Dry Weight The varieties showed significant differences for shoot and root length (cm) as well as for seedling dry weigh (g) at p<0.01(Figure 2, Figure 3 and Figure 4, respectively). However, interaction between variety x priming were not significant for these traits .The data regarding mean number of shoot length, root length

and seedling dry weight has been presented in the Figures 2 and 3.The longest shoot and root length were demonstrated by variety DZ-10-4. However, there was similar result between DZ-10-4 and Arerti for root length. Akaki and DZ-10-11 failed to show significant differences between themselves for shoot length. There was no significant difference between Habru and Natoli for shoot length. Furthermore, the data depicted that similar effects were obtained among Habru, DZ-10-11, Akaki and Natoli for root length under laboratory condition during germination test (Figures 2A and 2B). Variety Natoli produced the highest seedling dry weight followed by Arerti. However, variety DZ-10-4 produced the lowest seedling dry weight but it had similar dry weight with that of DZ-10-11.The seedlings from the chickpea varieties Habru, DZ-10-11 and Akaki had accumulated identical dry weight( incubated in the growth chamber for 8 days at an average temperature of 25

oC( Figure 4A).

There were also significant (p<0.01) differences due to priming media for all the three traits. Different seed priming treatments affected the vigorsity of chickpea variety significantly in terms of shoot length, root length, and seedling dry weight respectively as indicated in Figure 2, Figure 3 and Figure 4.As it can be seen, shoot length, root length (Figures 2B and 3B) and seedling dry weight (Figure 4B) followed a trend similar to seedling vigor index II. Seeds primed in solution of 0.5% KH2PO4 had the maximum shoot length, root length and seedling dry weight, followed by water treatment despite similar results were exhibited for the shoot length, root length and seedling dry weight due to hydro priming and osmopriming. KH2PO4 (0.5%) treatment enhanced both shoot and root length by 14%


Figure 2. Effect of variety on seedling shoot length (A) and Effect of priming medium on seedling shoot length (B) Bar graphs designated by the same letters are not significantly different from each other at p<0.05.

Figure 3. Effect of variety on seedling root length (A) and Effect of priming medium on seedling root length (B)

(Figure 2B and 3B) and seedling dry weight by 17% compared to the control. There were similar effects between hydro and osmo priming for shoot length, root length and seedling dry weight (Figure 4B). The minimum shoot and root length as well as minimum seedling dry weight was in the control where non-primed seeds were used (Figures 2B, 3B and 4B, respectively). Umairet al. (2010) reported that priming mungbean (Vigna radiata L.) with water and 0.6%KH2PO4 for five hours improved the growth of shoot and root length and also increased seedling dry weight under laboratory

conditions. Grandi et al. (1999) also found that P enrichment by soaking in 0.2% KH2PO4 solution improved the seedling establishment of common bean. The increased vigor of P-enriched seed might be due to increased P content both inside the seeds and on the seed surfaces which can lead to better establishment of seedlings (Ros et al., 2000). Similarly, the increase in seedling vigor may be due to enhanced oxygen uptake and the efficiency of mobilizing nutrients from the cotyledons to the embryonic axis (Kathiresan et al., 1984) and decreased catalase and peroxidase levels as recorded in pea seedlings (Srivastava and Dwivedi, 1998).Root and shoot lengths are the most important

Figure 4. Effect of Variety on seeddling dry eweight(A) and Effect of Priming medium on seedling dry weight (B) Bar graphs designated by the same letters are not significantly different from each other at p<0.05

Table 6. Interaction effect of priming media x varieties on the Emergence Index

Varieties Priming media Mean

Control Water KH2PO4(0.5%)

DZ-10-4 6.41

ij 5.94

ij 5.18

j 5.84

d

Arerti 8.59fgh

10.61abc

9.43cdef

9.37b

Habru 8.38efg

9.12def 7.30

ihg 8.27

c

DZ-10-11 9.66bcde

11.61a 10.82

abc 10.7

a

Akaki 10.89ab

10.25abcd

6.35ij 9.16

b

Natoli 8.38efg

8.21fgh

6.78hi 7.79

c

Mean 8.63b 9.29

a 7.64

c 8.52

Variety Priming Variety x Priming

LSD(5%) 0.824 0.583 1.427

CV(%) 11.81

Means with the same letters are not significantly different from each other. And those means designated by different letters are

differed statistically at p<0.05. parameters because roots are in a direct contact with soil to absorb water and shoots supply it to the rest of the plant (Thakare et al., 2011). Furthermore, rapid embryo growth resulted when the obstacle to germination was removed as a result of changes taking place during seed priming. These changes include macromolecular synthesis, several enzymes activities, increase germination power and vigor and overcoming dormancy (Khan, 1992).

Emergence Index Effect of variety revealed significant difference for emergence index at P < 0.01. When averaged across the priming treatments, DZ-10-4 and DZ-10-11 showed lowest and the highest emergence index respectively. Arerti performed significantly greater emergence index than Habru, Natoli and DZ-10-4, but not from that of Akaki (Table 6).Next to DZ-10-4, Natoli had the smaller emergence index where as Arerti and Akaki took the


Table 7. Linear correlation Coefficients(r) between emergence index and vigor parameters tested in the

laboratory at 5% and 1% level of significance.

SGP SG VI VII SL RL DW EC

SGP 1.00

SG 0.26 ** 1.00

VI 0.22 0.59** 1.00

VII 0.35** -0.32** -0.15 1.00

SL -0.43** 0.39** 0.70** -0.55** 1.00

RL -0.22 0.28* 0.59** 0.01 0.48** 1.00

DW 0.08 -0.57** -0.43** 0.69** -0.53** -0.15 1.00

EC -0.43 ** -0.53** -0.23* 0.01 0.16 -0.08 0.39** 1.00

EI 0.60** 0.40** 0.20 -0.04 -0.15 -0.25* -0.14 -.50**

*, ** designated significant difference at p<0.05 and p<0.01 respectively. SGP= Standard germination percentage, SG= speed of germination, VI= Vigor index I, VII= Vigor index II, SL= Shoot length (cm), RL= Root length (cm), DW= Seedling dry weight (g), EI= Emergence index; EC= Electrical conductivity (μscm

1g

-1).

second place in the value of emergence index. With the same planting date, emergence index of the variety displayed significant variation across the priming treatments at p<0.01. In reference to seed invigoration treatments, osmopriming performed the least as compared to that of both water treatment and control. As a result, there was an increase in emergence index by 8% for hydro priming as compared to the control. However, there was a sharp decline in the emergence index by 18% upon using osmopriming as compared to water and also decreased by 11% as compared to the control. Therefore, water treatment performed better than both osmopriming and the control. In consistence with present result, Brar and Stewart (1994) reported that seed priming by soaking in water for 10 hours and some more hours followed by surface drying and sowing markedly improved the seedling emergence of sorghum. Associated with such greater seedling emergence were faster crop development, earlier flowering, maturity and higher yields. Harris (1996) also reported that soaking sorghum seeds for 10 hours advanced seedling emergence from the soil by 12 hours. Analysis of variation indicated that an interaction of variety x priming medium was significantly different for emergence index (P < 0.01). Trend of emergence index in different varieties revealed that upon priming the seeds with water, only Arerti and DZ-10-11 showed significant increase in the emergence index over the control by 24% and 20%, respectively, while that of

DZ-10-4, Habru, Akaki and Natoli were not different significantly from the control. When osmopriming was used instead of hydro priming, Habru and Akaki demonstrated significant decrease of 20% and 38%, respectively in the emergence index compared to water. So these two varieties performed better for this parameter with water priming than with osmo priming. However, the rest of the varieties showed similar response statistically for emergence index with water treatment and 0.5 % KH2PO4 solution. Comparing osmopriming with that of unprimed seeds, Natoli and Akaki varieties resulted in a sharp decline in emergence index whereas other varieties had similar responses to both osmopriming and the control. According to Taylor et al. (1998) the physiological basis for increasing seedling emergence of primed seeds might be due to early DNA replication, increased RNA and protein synthesis, greater ATP availability, faster embryo growth, repair of deteriorated seed parts, and reduced leakage of metabolites compared to the control. In addition to initiating metabolic events, hydro priming may also leach germination inhibitors from the seeds (Taylor et al., 1998). Such a removal of germination inhibitors may reduced the germination time so that increased seedling emergence index of primed seeds with respect to the control. Correlations between Emergence Index and Other Vigor Tests. Linear correlation analysis between emergence index and other vigor parameters showed that significant

associations were observed between emergence index and other vigor parameters tested in the laboratory such as speed of germination, root length, and electrical conductivity of seed leachates. Moreover, there was also positive and significant correlation(r=0.60) between standard germination and emergence index (Table 7). There was considerable positive (r = 0.40) and significant (P < 0.01) relationship between speed of germination and emergence index. While root length was correlated with emergence index (r = - 0.25, p=0.05) and their correlation was negative. Furthermore, there was also substantial significant (P < 0.01) and negative correlation (r = -0.50) between seedling emergence index and seed leachates electrical conductivity. In general, correlation comparison results showed that primed seeds with high rate of germination also resulted in high emergence index while a negative relationship was demonstrated by root length and electrical conductivity. A significant correlation between seedling emergence index and other vigor tests was reported by Kausar et al. (2009). Similarly, a significant correlation between seedling emergence index and vigor tests of speed of germination, root length and electrical conductivity was also reported by Karta (2009). However, different finding was reported by Tekrony and Egli (1991) who stated that some vigor tests such as conductivity test was not correlated with seedling emergence. CONCLUSION Farmers and researchers have recognized that poor crop establishment is one of the major bottlenecks for crop production. This is particularly a problem for post rainy crops like chickpea mainly grown in such a sub-optimal environment. Seed priming (pre-sowing soaking) has been offered as a solution to this problem that will maximize the probability of obtaining a good stand of healthy and vigorous plants. It is logical to propose that seed priming has low cost and low risk that would be appropriate for all farmers and it is a key technology to improve the livelihood of resource-poor farmers in the marginal environments. Therefore, in present study, it can be concluded that hydro priming can step-up economical benefit of chickpea growing farmers. ACKNOWLEDGEMENT The first and the foremost gratitude and praise goes to the Almighty God, who is helping me in every sect of my life to pass through the whole challenges and reach at this endeavor. My profound thanks are also extended to my younger sister Mrs. Gete Sori for unreserved financial and moral support and encouragement throughout the study.

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Accepted 5 November, 2014. Citation: Sori A (2014). Effect of hydro and Osmo priming on quality of Chickpea (Cicer arietinum L.) Seeds. International Journal of Plant Breeding and Crop Science, 1(2): 028-037.

Copyright: © 2014. Sori A. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

effect of hydro and osmo priming on quality of chickpea (cicer arietinum l.) seeds

Education

soaking seed

low quality seed

seed priming process

chickpea plant

chickpea varieties dz

yield of chickpea

productivity of chickpea

method of seed enhancement