EFFECT OF STORAGE TEMPERATURE OF SEED POTATOES ON GROWTH AND YIELD OF POTATO UNDER SHORT DAY CONDITIONS

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EFFECT OF STORAGE TEMPERATURE OF SEED POTATOES ON GROWTH AND

YIELD OF POTATO UNDER SHORT DAY CONDITIONS

R. EZEKIEL

Central Potato Research Institute, Shimla-171 00 I (HP)

Received on 5 Oct., 2001, Revised on 19 Sept., 2002

SUMMARY

The effect of storage temperature of seed potatoes on the growth and yield of potato under field conditions was investigated in a study conducted in the north Indian plains. Seed potatoes of four cultivars were stored in darkness at 4 and 12"C during 1995-96 and at 4, 12 and 20"C during 1996-97. Cvs. Kufri Sindhuri and Kufri Bahar aged more rapidly while Kufri Lalima and Desiree aged less rapidly. The response ofthe Dutch cultivar Desiree to ageing was similar to that of Indian cultivars. Physiological ageing of seed tubers was more rapid at 12"C than at 20"C. The plants raised from seed tubers stored at 4"C were more vigorous with more number of stem and high ground cover, and produced more number of tubers and higher yield. Storage at 12 and 20"C reduced tuber number and yield significantly. Desprouting of seed tubers before planting had no significant effect on tuber number in both the years. However, its effect on tuber yield was significant during the first year but non-significant during the second year.

Key words: Desprouted, physiological age, plant vigour, sprouted, storage temperature, yield.

INTRODUCTION

In the Indo-Gangetic plains of north India, potato is planted in October and harvested during February-March. Seed potatoes harvested in February-March are stored in cold store at 4°C until they are planted in October i.e. for a period of about 6-7 months. It is not known whether these tubers are in optimum physiological condition at the time of planting. Storage temperature affects the physiological age of the tubers, which is reflected in the sprouting behaviour of the seed potatoes and their subsequent growth pattern when planted. The physiological age of a seed tuber is reflected in its growth vigour (Zaag and Van Loon 1987). The effect of storage temperature on the physiological age of seed tubers and their subsequent growth and yield have been studied in Dutch varieties by the Dutch Working Group (1987). Such a comprehensive study has not been conducted in the sub-tropical countries. Information on the physiological age of seed tubers and their growth and yield under field conditions is totally lacking in Indian varieties. The aim of this investigation was to study the effect of storage

Indian J. Plant Physiol., Vol. 7, No.4, (N.S.) pp. 343-348 (Oct.-Dec., 2002)

temperature on the physiological age of seed tubers at the time of planting, the subsequent f,'TOwth vigour and final yield of some popular Indian cultivars. An attempt has also been made to determine whether the seed tubers stored in cold store at 4°C has the optimum physiological age at the time of planting and whether it would be beneficial to increase the physiological age of seed tubers by storing them at higher temperatures.

MATERIALS AND METHODS

The experiment was carried out at Central Potato Research Station, Modipuram, (29° 4N, 77 46' E, 237m aboveMSL). ThecultivarKufri Baharwaschosen because of its short dormancy and cultivars Kufri Lalima and Kufri Sindhuri were chosen because of their long dormancy. In 1996-97, instead of Kufri Sindhuri the Dutch cultivar Desiree which is reported to have a long dormancy (Ittersum et al. 1992) and age slowly during

storage (Hartmans and Van Loon 1987) was included in the experiment for comparison. In both the years, seed tubers weighing 50-60g were planted at a spacing of 60 x

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20 em and the plot size was 9m2

. Factorial Randomized Complete Block design was followed and replicated three times. Fertilizer was applied to the sandy loam soil at the rate of 150 kgN, 80 kg Pp5 and 100 kg K20 per hectare.

In 1995-96, the seed crop was harvested in the first week of March and stored at room temperature until 30-3-1995. The seed tubers were stored at 4 and l2°C in darkness from 1-4-1995 until planting. In 4°C treatment, the seed tubers were pre-sprouted for 10 days before planting. The field experiment was planted on 28-10-1995. At the time of planting, the seed tubers were desprouted and planted in one treatment and in the other they were planted with sprouts, i.e. undesprouted. At the time of planting the physiological age of tubers stored at 4°C and pre-sprouted for 10 days at room temperature (this is the normal practice) was 260 day-degrees and that of tubers stored at l2°C was 1688 day-degrees. Sprout number per tuber and length of the longest sprout were recorded on 30 tubers in each treatment at the time of planting. In 1996-97, the seed crop was harvested in the first week of March and the harvested seed tubers were stored at room temperature until 30-3-1996. The tubers were stored at 4°C on 1-4-1996. Half the quantity was shifted to 20°C on 25-6-1996. Tubers stored at 20°C were stored initially for about three months at 4°C in order to avoid excessive ageing. Tubers stored at 12 and 20°C had physiological ages of 15 92 and 1808 day-degrees respectively. As in 1995-96, the seed tubers were desprouted and planted in one treatment and in the other they were planted with sprouts, i.e. undesprouted. Sprout number per tuber and length of the longest sprout were recorded on 30 tubers in each treatment at the time of planting.

During the growing season, observation were recorded on plant emergence by counting the number of plants, time of tuber initiation by checking four plants per plot in border rows on alternate days, ground cover following the method ofBurstall and Harris ( 1983) and stem number by counting the number of stems per m2

. At final harvest

tuber number and yield/m2 were recorded.

RESULTS AND DISCUSSION

Tuber characteristics

At planting in 1995, in seed tubers stored at 4°C and pre-sprouted, the number of sprouts per tuber were 6.0,

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5.6 and 5.3 in Kufri Bahar, Kufri Lalima and Kufri Sindhuri respectively. The corresponding values for sprout length were 1.0, 1.1 and 0.6 em respectively. The number of sprouts decreased and sprout length increased in l2°C treatment. The sprout number per tuber were 2.0, 2.0 and 1.3 in Kufri Bahar, Kufri Lalima and Kufri Sindhuri respectively. The corresponding values for sprout length were 18, 20 and 24 em respectively. At planting in 1996 in seed tubers stored at 4°C and pre-sprouted, the number of sprouts per tuber were 7 .0, 4.2 and 5.0 in Kufri Bahar, Kufri Lalima and Desiree respectively. The corresponding valuesforsproutlengthwere 1.5, 1.3, l.Ocmrespectively. Thenumberofsproutsin l2°Ctreatmentwere 1.0, 1.0, 1.0 in Kufri Bahar, Kufri Lalima and Desiree respectively. The corresponding values for sprout length were 15, 18.5 and 24.2 em respectively. When the tubers were stored at 20°C, the sproutnumberpertuberwere 3.0, 2.0, 2.2 in the above three cultivars respectively. The corresponding values for sprout length were 10.4, 20.6 and 17.8 em respectively. The sprouts were unbranched at l2°C and branched at 20°C with 3-4 branches.

Emergence and tuber initiation

There was no significant difference between treatments in the time taken for emergence. However, emergence was delayed by about 7 days when the seed tubers were desprouted before planting. Similarly there was no significant difference in the time taken for tuber initiation between treatments but the tuber initiation was delayed by 7 days in case of desprouting.

Plant characteristics

The number of main stems in 4°C treatment was higher than that in 12 and 20°C treatments (Table 1 ). There was no significant difference in stem number due to desprouting in 4°C treatment but desprouting caused reduction in stem number in the other two treatments. When seed tubers were stored at 4°C and plante<J after desprouting, the stem girth was 3.1, 3.8 and 3.6 em in KufriBahar,KufriLalimaandKufriSindhurirespectively. The corresponding values for 12°C were 2.6, 2.9 and 2.2 em respectively. Similarly, when seed tubers were stored at4°C and planted without desprouting, the stem girth was 3.3, 3.3 and 3.7 cminKufriBahar,Kufri LalimaandKufri Sindhuri respectively. The corresponding values for l2°C

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Table 1. Effect of seed storage temperature on stem number/m2 of three potato cultivars

Cultivar

Kufri Bahar Kufri Lalima Kufri Sindhuri Mean

LSD (P = 0.05)

Kufri Bahar Kufri Lalima Desiree Mean 4•C 35.0 35.0 38.0 36.0 T: 2.7, 28.0 28.3 29.6 28.6 Desprouted 12•C 21.0 17.0 17.3 18.3

S: N.S., C:N.S., TxS: 3.8,

14.7 18.0 13.7 15.5

20'C 4'C

1995-96

36.0 33.0 33.0 34.0 TxC: N.S., SxC :N.S.,

1996-97

17.3 27.7

21.3 26.3

19.7 28.3

19.4 27.4

Un-desprouted 12'C 26.0 25.0 25.3 25.3 TxSxC: N.S.

16.7 24.0 24.0 21.6 20'C 21.7 20.0 25.0 22.2 LSD (P ~ 0.05) T: 2.9, s: 2.4, C: N.S., Interaction : N.S.

T. Temperature, S : Sprouting, C : Cultivar, N .S :Non-Significant

were 3.3, 2.8 and 2.5 em respectively. Thus seed tubers stored at l2°C produced thinner stems causing the plants to lodge earlier than that in 4°Ctreatment. Percent ground cover was higher in 4°C treatment and was not affected by desprouting (Table 2). The crop cover was less in 12°C and was poorly developed in desprouted tubers. There

was no significant difference between 12 and 20°C (Table 2).

The number of tubers produced per m2 were more in 4°C treatment when compared to the other two treatments (Table 3). There was no significant difference between 12

Table 2. Effect of seed storage temperature on ground cover(%) at 60 days after planting in three potato cultivars

Cultivar

Kufri Bahar Kufri Lalima Kufri Sindhuri Mean

LSD (P = 0.05)

Kufri Bahar Kufri Lalima Desiree Mean 4'C 71 82 93 82.0 T: 4.8, 53 5 I 56 53.3 Desprouted 12'C 29 38 22 29.7

s:

4.8, c: 5.9,

39 51 41 43.7

U n-desprouted

20•C 4'C 12'C

1995-96

84 63

79 70

93 69

85.3 64.0

TxS: 4.8, TXC: 5.9, SxV: N.S., TxSxV: 5.9 1996-97

40 58 50

48 58 45

44 53 45

44.0 56.3 46.7

LSD (P = 0.05) R: 12.4, S: N.S., c: 12.4, TxS: 12.4, TxC: 8.01, sxc: 12.4, TxSxC: 8.01

Indian J. Plant Physiol., Vol. 7, No.4, (N.S.) pp. 343-348 (Oct.-Dec., 2002)

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and 20°C treatment in tuber number. Tuber number per unit area was not affected by desprouting. Seed tubers· storedat4°C gavemaximumyield(Table4). Storage at 12 or 20°C caused ageing of tubers leading to reduction in

yield. The yield reduction was greater in l2°C treatment than in 20°C treatment.

There are conflicting reports on the effect of physiological age of seed tubers on the emergence. 0'

Table 3. Effect of seed storage temperature on tuber number/m2 of three potato cultivars

Cultivar Desprouted Un-desprouted

4"C n·c zo·c 4•C 12•c 20"C

1995-96

Kufri Bahar 94.0 40.0 98.0 78.0

Kufri Lalima 92.0 77.0 82.0 83.0

Kufri Sindhuri 146.0 77.0 128.0 98.0

Mean 110.7 64.7 102.7 86.3

LSD (P = 0.05) T: 11.4, S: N.S., c: 13.9, TxS: 16.1, TxV: 19.7, SxV: N.S, TxSxV: N.S. 1996-97

Kufri Bahar 45.0 37.0 30.0 45.0 35.0 35.7

Kufri Lalima 64.3 51.0 45.3 67.0 55.3 51.7

Desiree 47.0 36.0 34.0 40.0 38.7 32.3

Mean 52.1 41.3 36.4 50.7 43.0 39.9

LSD (P = 0.05) T: 7.2. S: N.S., C: 7.2. Interaction: N.S.

Table 4. Effect of seed storage temperature on tuber yield (t/ha) of three potato cultivars

Cultivar Desprouted U n-desprouted

12"C 20"C 4•C 12"C

1995-96

Kufri Bahar 28.9 12.8 31.3 27.8

Kufri Lalima 3.73 30.5 364 32.1

Kufri Sindhuri 38.4 13.8 43.0 32.6

Mean 34.9 19.0 36.9 30.8

LSD (P = 0.05) T: 3.2, s: 3.2, c: 3.9, TxS: 4.5, TxC: 5.5, SxC: 5.5, TxSxC · ~.S. 1996-97

Kufri Bahar 23.7 15.9 20.9 27.2 18.4 24.0

Kufri Lalima 28.9 18.9 20.6 29.5 21.9 24.0

Desiree 17.6 12.4 13.9 16.3 13.6 I 5.1

Mean 23.4 15.7 j 8.5 24.3 17.9 21.0

LSD (P = 0.05) T: 2.8, S: N.S., c: 2.8, Interactions: N.S.

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Brien eta!. (1983) found that physiologically older seeds

emerged faster than younger seeds, whereas, Loon ( 1987) observed that physiologically older seeds stored at 12°C emerged more slowly than seeds stored at 4°C. This trend was observed even when the seed tubers were desprouted before planting. In the above study there was no significant difference in the time taken for emergence and tuber initiation (data not shown) when the tubers were planted with their sprouts intact. However, emergence and tuber initiation were delayed by about 7 days when the seed tubers were desprouted before planting, when compared to those tubers planted un-desprouted. This is to be expected since well sprouted tubers lead to early emergence. Reduction in stem number, stem girth and ground cover in 12°C treatment reflected the reduced growth vigour caused by ageing of seed tubers by storing at 12°C. Shoot growth at approximately 60 days after planting (DAP) can be taken as measure of relative growth vigour (Zaag and Van Loon 1987). Ground cover measured 60 DAP reflects the size of foliage produced by seed tubers stored at different temperatures and reduced ground cover is a reflection of reduced growth vigour. My results agree with the conclusion of Zaag and Van Loon ( 1987) that the growth vigour of seed stored at 4°C is higher than that of seed stored at l2°C and higher storage temperature decreases the maximum growth vigour. The reduction in growth vigour was drastic when the tubers were desprouted. This agrees with the finding of Loon ( 1987) who also de sprouted the seed tubers before planting.

In all the three cultivars the number of stems produced per plant and therefore per unit area were more in 4°C treatment. This is in agreement with the results of Bodlaender and Marin us (1987) and Allen et al. ( 1987).

When the tubers were stored at 4°C, the apical dominance phase was passed during the storage itself, therefore, the tubers produced multiple sprouts when pre-sprouted, which in tum lead to more number of stems. On the other hand when tubers were stored at 12 and 20°C, the tubers were in their apical dominance stage when sprouting occurred, therefore fewer sprouts and hence fewer stems were produced. When tubers were planted without desprouting, there was no significant difference in the number of stems produced between 12 and 20°C treatments but when planted after desprouting, the stem number was less in 12"C than in 20°C treatment.

Indian J. Plant Physiol., Vol. 7, No.4, (N.S.) pp. 343-348 (Oct.-Dec., 2002)

The number of tubers produced differed between treatments and the number of tubers were related to the

.

number of stems produced. In 12°C treatment, fewer stems led to less number of tubers when compared to 4°C. During 1995-96, 4°C treatment produced more tubers and there was no significant difference between 12 and 20°C. Physiologically younger tubers (stored at 4°C) produced maximum yield in both the years. This is in agreement with the results oflritani (1968) and Loon ( 198 7). However, Loon (1987) did not observe significant difference in yield of Desiree between 4 and 12°C treatments. In the present study tubers of Desiree stored at 4°C gave higher yield than those stored at 12°C and 20°C and the yield difference was more marked when the seed tubers were planted after desprouting. One possible reason for this contrasting result could be that in Loon's experiment, the crop was raised under temperate, long day conditions while in this case the crop was grown under subtropical, short day conditions. The Dutch cv. Desiree is reported to age slowly unlike the cv. Jaerla, which ages rapidly, physiologically (Hartmans and Van Loon 1987). However the studies revealed that the response of Desiree to physiological ageing was similar to the other two Indian cultivars and its yield was less than that of the other two cultivars. This could be attributed to the fact that Indian cultivars were bred for the subtropical short-day conditions whereas the Dutch cv. Desiree was developed for the long-day conditions of Europe.

While the difference in tuber number due to desprouting was statistically non-significant in both the years, differences in stem number and tuber yield were significant in the first year and non-significant in the second year. But in general terms, the effect of physiological age was seen more clearly when the tubers were desprouted before planting. Zaag and Van Loon (1987) suggested that while studying the physiological age of seed tubers on crop growth, it is better to have tubers with similar sprout length at planting so that the observed differences in the crop growth and yield can be attributed to the differences in the physiological age of the tubers and not to the differences in sprout length at planting.

The results reported here are in agreement with the observation of Kawakami (1962) that when seed tubers are planted after the proper age plant development will be

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slower and yields will be sub-optimal. It should be noted here that though the tubers stored at 20"C were physiologically older in terms of day-degrees than those stored at 12"C, the reduction in growth vigour and yield were more at 12"C. The possible explanation could be that in tubers stored at 12"C, the sprout growth was excessive leading to greater exhaustion ofthe tubers. Desiree appears to be more tolerant to ageing as reflected in the per cent reduction in yield due to storage at higher temperatures. Amongst the Indian cultivars Kufri Sindhuri and Kufri Bahar were more susceptible to ageing.

ACKNOWLEDGEMENT

I thank Mr. Harvir Singh for his technical assistance. I am thankful to the Director, CPRI, Shimla and Joint Director, CPRS, Modipuram for providing the facilities.

REFERENCES

Allen, E.J., Bean, J.N. and Griffith, R.L. 1978. Effects of low temperature on sprout -growth of several potato varieties. Potato Res. 21: 249-255.

Bodlaender, K.B.A. and Marinus, J. 1987. Effects of physiological age on growth vigour of seed potatoes of two cultivars. 2. Effect on plant growth under controlled conditions. Potato Res. 30: 423-440.

Burstall, Land Harris, P.M. 1983. The estimation of percentage light interception from leaf area index and percentage ground cover in potatoes. J. Agric. Sci. Cambridge 100: 241-244.

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Hartrnans, K.J. and Van Loon C. D. 1987. Effect of physiological age on growth vigour of seed potatoes of two cultivars. l. Influence of storage period and storage temperature on sprouting characteristics. Potato Res. 30: 397-409.

Iritani, W. M. 1968. Factors affecting physiological ageing (degeneration) of potato tubers used as seed. Am. Potato J. 45: 111-116.

Jttersum, M.K., van Aben, F.C.B. and Keijzer, C.J. 1992. Morphological changes in tuber buds during dormancy and initial sprout growth of seed potatoes. Potato Res. 35: 249-260.

Kawakami, K. 1962. The physiological degeneration of potato seed tubers and its control. Eur. potato J. 5: 40-49.

0 Brien, P.J., Allen, E.J., Bean, J.N., Griffith, R.L., Susan A. Jones and Jones, J.L. 1983. Accumulated day-degrees as a measure of physiological age and the relationships with growth and yeild in early potato varieties. J. of Agric. Sci. Cambridge I 01: 613-631.

Van Loon, C.D. 1987. Effect of physiological age on growth vigour of seed potatoes of two cultivars. 4 Influence of storage period and storage temperature on growth and yield in the field. Potato Res. 30 : 441-450.

Working group, 1987. Effect ofphysiologcal age on growth vigour of seed potatoes of two cultivars. IBVL Wageningen, The Netherlands.

Zaag. D.E. and Van Loon, C. D .. 1987. Effect of physiological age on growth vigour of seed potatoes of two cultivars. 5 Review of literature and integration of some experimental results. Potato Res. 30:451-472.

Figure

Table 1. Effect of seed storage temperature on stem number/m2 of three potato cultivars

Table 1.

Effect of seed storage temperature on stem number/m2 of three potato cultivars p.3
Table 2. Effect of seed storage temperature on ground cover(%) at 60 days after planting in three potato cultivars

Table 2.

Effect of seed storage temperature on ground cover(%) at 60 days after planting in three potato cultivars p.3
Table 3. Effect of seed storage temperature on tuber number/m2 of three potato cultivars

Table 3.

Effect of seed storage temperature on tuber number/m2 of three potato cultivars p.4
Table 4. Effect of seed storage temperature on tuber yield (t/ha) of three potato cultivars

Table 4.

Effect of seed storage temperature on tuber yield (t/ha) of three potato cultivars p.4

References