Effect of Different Chemicals on Eliminating the Dormancy Period of Freshly Harvested Seed Potatoes

Muhammad Junaid Zaghum^1-3*, Ali Zohaib^1,3, Muhammad Nouman Khalid³, Ghulam Muhy Ud Deen¹, Armaghan Ahmad¹ and Syed Sajid Hussain Zaidi⁴

¹Seed Science and Technology, Department of plant breeding and genetics, University of Agriculture, Faisalabad, Pakistan
²Seed physiology Laboratory, Department of Agronomy, University of Agriculture Faisalabad, Pakistan.
³Department of plant breeding and genetics, University of Agriculture, Faisalabad, Pakistan
⁴Plant Virology Section, Plant Pathology Research Institute, Ayub Agriculture Research Institute, Faisalabad, Pakistan

*Corresponding Author: Muhammad Junaid Zaghum, Department of plant breeding and genetics, University of Agriculture Faisalabad, Pakistan.

Received: December 26, 2020; Published: February 15, 2021

Citation: Muhammad Junaid Zaghum., et al. “Effect of Different Chemicals on Eliminating the Dormancy Period of Freshly Harvested Seed Potatoes”. Acta Scientific Agriculture 5.3 (2021).

Abstract

  A study was conducted to investigate the response of freshly harvested seed potatoes treated with Sugar (C12H22O11), Gibberellic Acid (C19H22O6), Thiourea (CH4N2S), and Ethanol (C2H5OH) to find out which chemical treatment has more effectiveness for the elimination of dormancy period. Freshly harvested seed potatoes were collected from Plant Virology Section Research Area, Ayub Agricultural Research Institute, Faisalabad. Solanum tuberosum is a perennial because it is commercially propagated from tuber. In seed potato the normal dormancy period is 7-19 weeks. Results shows that treatment of 300g sugar powder in 600ml water eliminates the dormancy within 12-16 days at open light condition. Treatment with 600g sugar powder in 600ml water breaks the dormancy within 17-18 days at open light. Treatment with 300g sugar powder dry coating on wet surface of tuber eliminate the dormancy within 18-24 days at dark condition. Treatment with 1% TU and 1g GA3 in 1000ml solution can eliminate the dormancy within 18 days at open light and dark conditions. 250ml solution of EtOH can eliminate the dormancy period within 24-26 days at open light and semi dark condition. The application of dormancy breaking chemicals such as sugar, gibberellic acid, thiourea and ethanol induces metabolic changes that lead to dormancy elimination and also from those occurring when dormancy is eliminate naturally. The present study exposed that under open light condition treatment of 300g sugar powder in 600ml water solution gave best results of tubers sprouting as compared to other treatments.

Keywords: In vitro; Perennial; Dormancy; Growth Regulators

Abbreviations

S: Sugar; GA3: Gibberellic Acid; TU: Thiourea; EtOH: Ethanol; C: Control.

  Seed Potato is a primary storage organ of starch and one of the major human food sources [1]. It belongs to family Solanaceae. Potato crop is ranking at 4th number of vegetable crops [2]. The potato family includes mainly herbaceous plant species and contains 70% water, 18% starch and 2% protein, whereas a 1% vitamin, mineral and trace element have been recorded [3]. Potatoes are rich in protein, calcium, vitamin C and have an especially good amino acid balance [4]. Potatoes are also a valuable source of nutrition in many developing countries, contributing carbohydrates, vitamins and minerals to the diet of millions [5]. In potato tubers, there are three phases of dormancy. The first phase of dormancy is called endodormancy where, even under ideal conditions, endogenous factors limit the development of sprouts. During the second stage of dormancy, the growth is restricted by external physiological factors, called paradormancy. The third stage of dormancy refers to ecodormancy during which external environmental factors interrupt meristematic development [6]. Tubers are endodormant immediately after harvest and do not produce sprout if kept at temperatures 3˚C [7]. Dormancy is known as a condition for survival. The life cycle of a potato tuber is characterized by the initiation and growth followed by a period of dormancy and finally sprouting resulting in the next generation [8]. The time of tuber initiation is until the breakdown of dormancy of potato tuber. As might be predicted from a developmental feature that gives a protective effect, the ancestry trend in tuber dormancy is complicated and regulated by nine different loci [9].

  Endogenous hormones have been proposed to play a significant role in potato tuber bud dormancy regulation [10]. There are following methods that are used to eliminate seed dormancy. These methods are scarification, stratification, temperature treatment, light treatment and treatment with growth regulator i.e., gibberellic acid, thiourea, ethanol, cytokines, ethylene and other chemicals [11]. After the breakdown of dormancy, gibberellins help trigger bud activation, but the maintenance of dormancy may not be related to endogenous concentration [12].

  Plant growth hormones have been suggested to play a prominent role in the control of tuberization [13]. Sprouting is one of the most physiological processes affecting postharvest tuber quality. This process is accompanied by other physiological and biochemical changes, including increases in respiration, water loss, reducing sugar content and glycoalkaloid content [14]. Potato tuber dormancy, which is considered to be a condition of physiological rest, is reported to start at the beginning of tuber initiation and continue until 6 to 12 weeks after harvest, depending on varietal characteristics [15].

  Potato dormancy depends according to genotypes. It can also differ from a specified location or year in a tuber lot of one cultivar [16]. The genetic component, the tuber dormancy genetic basis, is complicated and many loci regulate it. The natural development of dormancy exists in many potato cultivars over a span of several months [6]. Typically, in early varieties, the dormancy period is shorter than in later cultivars, although this relationship is not very formal [17]. Furthermore, prolonged tuber dormancy is usually observed in populations of wild potatoes, while the alternative also exists in lines of potatoes produced through conventional breeding [18]. The duration of the dormancy cycle relied on the inherited history and influenced by the conditions pre- and post-harvest [19]. A variety of exogenous compounds that eliminate dormancy from field growing tubers, but specific micro-tuber assessments have been minimal. The dormancy duration and sprouting behavior are major criteria for the quality of a particular potato clone that should be recorded before any successful clone produced. Evident faint white buds distinguish the earliest detectable sprouting stage [17]. Whether it had some sprouts of 2 mm in length, a tuber considered sprouted, counted as peeping tuber with clear sprouts < 2 mm in length [20].

Material and Methods

  Freshly harvested seed potatoes are obtained from Plant Virology Section Research Area, Ayub Agricultural Research Institute Faisalabad. This experiment was conducted in the green house of Plant Virology Section, Ayub Agricultural Research Institute Faisalabad. In vitro take 180 freshly harvested seed potatoes. Use 30 seed potatoes for each treatment. Apply recommended dose of chemicals to freshly harvested seed potatoes according to treatment table. After treatment use dark envelop and muslin cloth to cover potatoes and place under three different conditions at 22-25^oC. Daily observe it and start to take data on first number of potato sprout of any treatment. When 100% sprout complete stop to take data after the completion of sprouting the varieties of potato tubers were sown in earthen pots measuring 30 x 40cm containing garden soil and sand. The plants were watered on weekly basis.

Table of treatments

Treatments	No of Potatoes	Dose of Chemicals			Duration	Condition 22-25oC
Thiourea (TU) + Gibberellic acid (GA3)	30	1% solution + 1000ppm solution			Dipped for 1 hour in thiourea. After thiourea dipped for 15-20 minutes in gibberellic acid	Dark
						Semi Dark
						Open Light
Ethanol (EtOH)	30	250ml solution			Dip for 30 seconds in Ethanol	Dark
						Semi Dark
						Open Light
Sugar (S)	30	T1	Thick Solution of Sugar Powder	400g in 600ml	Dip for 5-10 minutes in Thick Solution	Dark
						Semi Dark
						Open Light
	30	T2	Spray of Sugar Powder	300g in 600ml	Spray till 2-3 minutes	Dark
						Semi Dark
						Open Light
	30	T3	Dry Coating of Sugar Powder on Wet Tuber Surface	300g	Placement of Tubers in open light for 30 minutes after coating	Dark
						Semi Dark
						Open Light
Control (C)	30					Dark
						Semi Dark
						Open Light

Table a

Results and Discussion

Results of different treatments in table form are given below.

Condition	Treatment	D-O-T	Tubers	12D	14D	16D	18D	20D	22D	24D	S.P
Dark	Thiourea + Gibberellic Acid	14/3/19	10	1	1	1	1	4	4	7	70%
Semi Dark		14/3/19	10	2	2	2	2	3	4	5	50%
Open light		14/3/19	10	2	3	3	4	4	6	6	60%

Table 1: Result of Thiourea and Gibberellic acid Treatment.

  Treatment with 1% thiourea and 1g gibberellic acid in 1000ml solution gave 70% sprout percentage at dark condition, 50% sprout percentage at Semi dark condition and 60% sprout percentage at open light condition within 12 days. The first number of sprout are start after 12 days of treatment.

Condition	Treatment	D-O-T	Tubers	12D	14D	16D	18D	20D	22D	24D	S.P
Dark	Ethanol	14/3/19	10	0	0	0	0	2	3	6	60%
Semi Dark		14/3/19	10	0	0	0	0	2	4	6	60%
Open light		14/3/19	10	0	0	1	1	2	2	2	20%

Table 2: Result of Ethanol Treatment.

  Treatment with 250ml ethanol solution gave 60% sprout at dark condition, 60% sprout at Semi dark condition and 20% sprout at open light within 24 days. The first number of sprout treated with ethanol are start after 15 days at open light and 20 days at dark and semi dark condition.

Condition	Treatment	D-O-T	Tubers	12D	14D	16D	18D	20D	22D	24D	S.P
Dark	Spray	15/3/19	10	0	2	2	2	4	4	5	50%
	Thick Sol.	15/3/19	10	0	1	1	1	2	2	2	20%
	Spray + D.C.	15/3/19	10	0	1	1	1	3	6	6	60%
Semi Dark	Spray	18/3/19	10	2	2	2	3	3	5	5	50%
	Thick Sol.	18/3/19	10	0	0	1	1	3	3	3	30%
	Spray + D.C.	18/3/19	10	0	0	0	0	3	4	4	40%
Open light	Spray	18/3/19	10	4	7	7	7	7	7	10	100%
	Thick Sol.	18/3/19	10	2	4	4	4	4	6	6	60%
	Spray + D.C.	18/3/19	10	0	2	2	2	3	3	4	40%

Table 3: Result of Sugar Powder Treatment..

  Sugar powder can be use by 3 different modes of replication. Sugar powder solution spray, sugar powder thick solution and sugar powder solution spray and dry coating. Treatment with 300g sugar powder in 600ml water solution gave 50% sprout percentage at dark condition, 50% at semi dark condition and 100% at open light within 12-16 days. The sprouts are started after 6 days of treatment. Treatment with 400g sugar powder in 600ml water as thick solution gave 20% sprout at dark condition, 30% sprout at semi dark condition and 60% sprout at open light with in 24days. The sprouts are started after 8 days of treatment. Treatment with 300g sugar powder in 600ml water and 300g dry coating gave 60% sprout percentage at dark condition, 50% sprout percentage at semi dark condition and 40% sprout percentage at open light condition. The first number of sprouts are start after 14 days of treatment.

Condition	Treatment	D-O-T	Tubers	12D	14D	16D	18D	20D	22D	24D	S.P
Dark	Control	14/3/19	10	0	0	0	0	0	0	0	0%
Semi Dark		14/3/19	10	0	0	0	0	0	0	0	0%
Open light		14/3/19	10	0	0	0	0	0	0	0	0%

Table 4: Result of Control Treatment.

Treatment with control gave 0% sprout percentage at dark, semidark and open light condition.

Graphs of sprout percentage

Graph indicate the different treatment results at different conditions. Best results are given by.

Figure 1

  At dark condition the number of percentage of sprout of treatement with 1g gibberellic acid and 1% thiourea in 1000ml solution is 70%, 250ml ethanol solution is 60%, 300g sugar powder and 600ml water is 50%, 400g sugar powder and 600ml water as a thick solution is 20% and 300g sugar powder solution and 300g dry coating is 60%. The control treatment is 0% until the treatment ends.

Figure 2

  At semi dark condition the number of percentage of sprout of treatement with 1g gibberellic acid and 1% thiourea in 1000ml solution is 50%, 250ml ethanol solution is 60%, 300g sugar powder and 600ml water is 50%, 400g sugar powder and 600ml water as a thick solution is 30% and 300g sugar powder solution and 300g dry coating is 40%. The control treatment is 0% until the treatment ends.

Figure 3

  At open light the number of percentage of sprout of treatement with 1g gibberellic acid and 1% thiourea in 1000ml solution is 60%, 250ml ethanol solution is 20%, 300g sugar powder and 600ml water is 100%, 400g sugar powder and 600ml water as a thick solution is 60% and 300g sugar powder solution and 300g dry coating is 40%. The control treatment is 0% until the treatment ends.

Conclusion

Yield performance of the varieties

  It is concluded that in vitro 30 seed potatoes treated with 300g sugar powder in 600ml water in open light condition at 25oC gave good results with in minimum number of days as comparison with gibberellic acid, thiourea and ethanol. In Pots it also gave good germination response and also improve vigor. It is cheap chemical and easily available and applicable by the farmer’s community and potato growers for potato crop production.

Conclusion

Authors Contribution

  Conceived and design the experiment by Syed Sajid Hussain Zaidi and Muhammad Junaid Zaghum. Perform the experiment, record the data and wrote the paper by Ali Zohaib and Muhammad Junaid Zaghum.

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Copyright: © 2021 Muhammad Junaid Zaghum., et al. 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 credited.