EVALUATION OF GROUNDNUT GENOTYPES FOR PHOSPHORUS USE EFFICIENCY

btdlan J. Plant PhysiQl., Vol. XXXIV. No.3, pp. 228-~34 (Sept., t99l)

EVALUATION OF GROUNDNUT GENOTYPES FOR PHOSPHORUS USE EFFICIENCY

K.B. REDDY, D. SREENIVASA REDDY AND C. MASTAN REDDY

Sri Venkateswara Agricultural College, A.P., Agricultural University, Tirupati 517 502

Received on 14 June, 1991

SUMMARY

Efficiency of P utilization was studied in 20 groundnut genotypes under conditions of very low (3.1 mg kg-I), low (6.2 mg kg-I) and optimum (62.0 mg kg-I) P supply. Significant genotypic differences were found in P use efficiency. Shoot weight was found to be sensitive growth parameter to P deficiency. ICGS-ll recorded higher PER of 1130 among the genotypes tested. Based on the'phosphorus efficiency ratio (PER). the genotypes were classified into efficient, moderately efficient and inefficient in phosphorus utilization.

INTRODUCTION

Most cultivars have been selected for high yields under optimum fertilizer conditions. The possibility of exploiting genotypic differences in absorption and utilization of P to improve efficiency of P fertilizer use or to obtain higher produc­ tivity on P deficient soils has received considerable attention in recent years (Fageria and Filha, 1982; and Sivasankar et ai., 1987). Such studies have great practical utility when low nutrient availability in soils limits crop production.

PHOSPHORUS USE EFFiCIENCV IN GROuNDNUt

Reddy, 1983 and Sivasankar et al. 1987). However, the information available on groundnut genotypic differences to P deficiency and the properties which better define P efficiency is limited. The objective of this study was to compare the differences among groundnut genotypes for growth, P uptake and phosphorus efficiency ratio (PER) (mg dry weight produced per mg of P absorbed) when grown under varied levels of P in growth medium.

MATERIALS AND METHODS

The experiment was conducted in green house at Sri Venkateswara Agricultural College, Tirupati (l3°N, 79°E) to evaluate the response of 20 groundnut genotypes to different levels of soil pho~phorus. Plants were raised in pots each containing 50 kg of sandy loam soil having an available phosphorus in traces and initial pH was 7.6. Phosphorus was applied in the form of single super phosphate at very low (3,1 mg kg-I soil), low (6.2 mg kg-1 _{soil) and optimum (62.0 mg kg-I soil) concen­}

trations. The basal application of fertilizers in each pot was 987 mg of N as urea and 1959 mg of KzO as muriate of potash. Fertilizers were mixed with the soil thoroughly before filling the pots. The experiment was laid out with 20 genotypes and 3 phosphorus levels in a factorial randomized block design with 3 replications during the year 1990.

AlI pots were watered to maintain goil moisture at approximately field capacity throughout the growing period. The plants were harvested at 70 DAS and the roots were rinsed with distilled water several times. The growth parameters like plant height, tap root length and leaf area were recorded and the entire plant was separated into shoot and root. These parts were dried to a const&.nt weight in a forced air oven at 70°C for dry matter determination. Phosphorus content of plant samples was determined following the method described by Jackson (1958).

RESULTS AND DISCUSSION

Significant differences were observed among genotypes for plant height, leaf area, dry weight of shoot and root, total dry weight and P concentration in root and shoot (Table I). Significant differences were also observed between soil P treatments and interactions between genotypes and soil P treatments for aU the above parameters.

idi. RBDD'Y

et ai.

Table I. F-values for growth parameters, P concentration and P uptake of 20 groundnut genotypes

Source of variance Plant parameter

Genotypes Treatments GxT

(G) (T)

Plant height 2.17" 0.84"· 3.76··

Leaf area 18.00" 7.00" 31.34··

Root dry weight 0.05"· 0.02" 0.09··

Shoot dry weight 0.17·· 0.07*­ 0.29*·

Total dry weight 0.29*· 0.11·· 0.51··

P cone. in root 0.01·· 0.06·· 0.018­

P CODe. in shoot 0.004·· 0.001·· 0.006··

P uptake by root 0.046·· 0.018·· 0.079··

P uptake by shoot 1.17·· 0.453·· 2.03··

---.~.--.-~.

•• Significant at both 0.05 and 0.01 probability levels.

Table II. Influence of P levels on growth parameters, P concentrations and P uptake in 20 groundnut genotypes

---~---Growth parameterI Soil P levels

Plant P status

Very low Low Optimum

(3.1 mg kg-I) (6.2 mg kg-I) (62.0 mg kg-I)

Plant height 24.9 e 29.7 b 36.0 a

Tap root length 36.6 a 27.7 b 21.0c

Leaf area (em" plant-I) 963.5 c 1293.8 b 1622.1 a

Root dry matter (g plant-I) 0.49 c 0.54 b 0.62 a

Shoot dry matter (g plnnt-I ) _{5.96 c 7.69b 10.28 a}

P cone. in root (mg g-l) 0.085 c 0.126 b 0.190 a

P co!,!c. in shoot (mg g-l) 0.116 c 0.134 b 0.348 a

P uptake by root (mg plant-I) 0.41 c 0.68 b 1.25 a

P uptake by shoot (mg plant-I) 7.57c 11.50 b 36.02 a

-.--.--~~

Values under different levels of P followed by the same letter are not significantly different at the '0.05 level.

(1980) and Narayanan and Reddy (1982) in groundnut. Such increase waS consi­ dered as an adaptive mechanism of plants for exploring larger volume of soil to

~xtract adequate P. Application of phosphorus resulted in increase in all growth

1

1

I

and P uptake parameters (Table II) indicating that the soil used in the experiment was appropriate to study the differential response of crop plants to P stress.

Genotypes differed significantly with regard to dry matter (DM) production

i e., shoot and root weight at all the P levels (Table III). ICGS 11 produced higher shoot and total DM among the genotypes at the low level of P. Genotypes such as ICGS-ll, ICGS (E) 21 and Kadiri-3 }ielded better at low level of P and JL-24, Girnar. TCG-273. TCG-1704 and TCG·1704 and TCG 1518 responded better to added P. Genotypic differences were also observed in groundnut with regard to total DM production, concentration of P in shoot and P uptake (Reddy et ai, 1980; Sivasankar et aI., 1987).

Table III. Genotypic differences in total dry matter production (g planel ) as influenced by P levels in groundnut

.._______~_~_··· ___ _______ ~ ~~_ .._. ___~M_~~_..________ ___ ~ ~_

Soil P levels

Genotype

~---Very low %ROC Low ~,~ ROC Optimum

(3.1 mg ka-I) (6,2 mg kg-I) (62.0 mg kg_I)

TCO-I 9.00 d 34.8 10.38 gh 24.7 13.80 d

TMV-2 8.20 e 41.4 10.18 h 27.3 14.00 d

TCG-3 7.88 f 35.9 9.13 k 25.8 12.30 g

JL·24 9.32 c 43.9 13.50 a 19.0 16.67 a

SVOS-5 9.79b 38.6 12.94 b 28.8 1594 b

TCO-6 6.85 h 44.3 9.76 ij 20.6 12.29 g

TCG-273 7.33 g 43.6 10.47 gh 19.5 13.00 f

Gangapuri 8.04 e 40.4 9.02 k 23.7 11.82 h

Girnar 8.05 e 44.3 12.50 c 13.4 14.45 c

TMV-1O 7.88 f 34.0 9.50 j 20.4 11.94 h

ICGS-II 10.72 a 26.2 12.11 d 16.6 14.52 c

Kadiri-2 7.35 g 46.9 10.56 g 24.0 13.85 d

Kadiri-3 9.28 cd 28.5 11.55 e 10.9 12.96 f

TeG-1704 7.59 fg 38.6 10.40 gh 15.9 12.37 g

TCG-1518 7.73 f 39.4 11.08 f 13.2 12.76 f

TCG· I 706 5.83 i 78.2 9.44 j 28.9 13.27 ef

TCG-30 6.58 h 55.2 9.46 j 35.6 14.69 c

ICGS (E)-21 9.32 c 30.2 12.23 c 28.5 13.47 e

Co-I 7.91 ef 42.9 10.65 g 23.2 13.86 d

Kadiri-l 5.87 i 52.0 7.75 I 36.6 12.22 gb

~~ansin the same column followed by the same letter are not significantly different at S%

probability.

k.B. ilEbDY et

at.

Percentage increase in growth parameters at 6.2 and 62.0 mgkg....it soil P levels as compared to low soil P is presented in Table IV. Shoot dry weight followed by leaf area showed maximum increase with addition of P. This means that the response to P deficiency in shoot weight and leaf area was maximum. ' Shoot weight is much more easily determined compared to leaf area and can be used for P screening studies of groundnut under green house conditions. Increase in shoot weight was significantly correlated with the adQition of P at both 6.2 (r= 0.66*·. y=3.88+0.63 x) and 62.0 (r=0.52*, y=7.17+0.52~) mg kg-I of soil.

,

When efficiency was considered in terms of mg of dry matter produced per mg i of P absorbed (Phosphorus efficiency ratio, PER), genotypes showed significant

,

I

differences at all the three levels of phosphorus. PER was highest at the low level

of Pand decreased with increasing level of P in the growth medium iTable V); This

J

r

indicates that higher amounts of DM was produced per unit of absorbed P at low

-

.

levels of P. As the concentration of P in the growth medium increased, P uptake ! increased, but less dry matter was produced for each additional unit of absorbed P. ... Similar results were also obtained by Fageria (1976) and Fageria et al. (1988) for ~

rice cultivars. Among all the genotypes, leGS-II (Spanish group) recorded higher

PER of 1130 followed by leGS (E)-21 and Kadiri-3 at very low level of P. Cark ~.

i..

et al. (1977) studied sorghum lines grown in P deficient soil and found differences among genotypes in phosphorus efficiency ratios. Based on the PER at very low level of P, the genotypes were classified into three categories namely efficient (PER above 850), moderately efficient (PER above 800 and below 850) and inefficient (PER below 800). Among the 20 genotypes, three were efficient {leGS-H, leGS (E)·21

r

Table IV. Per cent increase in growth parameters at 6.2 and 62.0 mg kg_I bOil P levels as compared to low level of soil P

t

1

Soil P levels Growth. parameter

6.2 mgkg-' 62.0 mg. kg-I

Plant height 19.3 44.6

Leaf area 34.3 68.4

Root dry weight 10.2 26.5

Shoot dry weight 28.8 71.9

Percentage growth increase=

(Growth at 6.2 or 62.0 mg kg-1 _{P-Growth at low P) x 100}

PHOSPHORUS USB 2FPICTENCY IN GROUNJ)NtlT

233

Table V. Mean phosphorus efficiency ratio (mg dry matter produced/mg P absorbed) of 20 groundnut genotypes

P levels

Genotype

----

---­

Very low Low Optimum

(3.1 mg kg-I) (6.2 mg kg-l) (62.0 mg kg-1)

TCG·1 795 e 780 c 349 ab

TMV·2 818 cd 730 de 330b

. TCG-3 781

e

702 e 347 ab

lL-24 835 cdc 764 ed 371 a

SVGS-5 837 cd 7l6e 330b

TCG-6 659 g 712 e 340 ab

TCG·273 804 e 693 e 323 b

Gangapuri 837 cd 724 de 346 ab

Girnar 845 be 830b 343 ab

TMV-I0 824 cde 704 e 329 b

ICGS·ll 1130 a 915 a 335 b

Kadiri·2 844 be 749 de 367 ab

Kadiri-3 871 bc 852 b 337 b

TCG-1704 839 cd 738 de 346 ab

TCG-1518 841 be 753 d 3SOab

TCG-1706 834 cde 71ge 341 ab

TCG-30 787 e 706 e 341 ab

ICGS (E)-21 881 b 851 b 356 ab

Co-I 768 f 625 f 333 b

Kadiri-l 784 e 703 c 336 b

Means in the same column followed by the same letter are not statistically different at P=0.05.

and Kadiri·3) eleven were moderately efficient (JL-24. SVGS-5, TCG·273. Gangapuri, Girnar, TMV-2, TMV-JO, Kadiri-2, TCG·17C4, TCG·) j18 and TCG-1706) and six

were inefficient (TCG-I, TCG-3, TCG-6, TCG-30. Cool and Kadiri-l).

REFERENCES

Basha, M.S.K. and Rao, G.R. (1980). Effect of P deficiency on growth and metabolism in peanut. Indian J. Plant Physiol., 3 : 274-276.

Clark, R.B., Maranville, l.W. and Ross, W.M. (1977). Differential phosphorus efficiency in sorgbum p. 1-2. In : Proc. IOtb grain sorghum Res. Util. Conf., Wicbitaks.

Fagcria. N.K. (1976). Effect of P, Ca and Mg concentration in solution culture on growth and uptake of these ions by rice. Agron. J. 68: ;26-732.

234 &:.B. ltBDDY et al.

Fageria, N.K., Wright, R.J. and Baligat, V.C. (1988). Rice cultivat evaluation for phosphorus use efficiency. Plant and soil. 111 : 105·109.

Jackson, M.L. (1958). Soil chemical analysis, Pub. Comtable and Co. Ltd., London. pp. 152. " Nimiyanati, A. and Reddy, K.B. (1982). Effect of phosphorus deficiency on the form of plant root

system. Proc. Inter Nat. Symp. on Plant Nutrition, London 1 : 414-418.

Reddy, G.H. and Reddy, A.A. (1979). (".,auses for low yields of groundnut in six districts of Andbra Pradesh. A survey report. A.P. Agricultural University pp. 44-70.

Reddy, P.R., Subba Rao" I.V. and Rao, L.M. (1980). Groundnut physiology, Progress report.-l. APAU. Hyderabad, p. 101-104.