EFFECT OF STORAGE TEMPERATURE ON THE ...

J lndtan Pou uo Assac 2X ( I)

147-14X (2001)

EFFECT OF STO RAGE TEMPERATURE ON THE DEVELOPMENT OF INTERNAL SPROUTS AND LITTLE POTATOES IN SOME POTATO CULTIVARS

R Ezekie l' and Vijay Paul?

'Ce ntral Potato Resear ch Institute, Shimla 171 001 (HP)

2Central Potato Research Institute Camp us, Modipuram 250 110 (U P)

Abstract: Storage of seed tubers of six potato cultivars at 4°C for six months , followed by two months at 20°C with three desproutings at 30 days interval led to the development of " litt le potatoes " in all the s ix cultivars studied. Internal sprouting and internal tubers were observed in a few tubers of Kufri Sindhuri wh ile the other five cultivars showed no internal sprouting and internal tubers . Formation of "little potatoes" was induced on dark and light grown sprouts of physiologically old tubers by giving low temperature tre atment.

W hen pota to seed tubers are stored at higher tem perature they become physiologically too old and 'little potatoes ' deve lop on the mot he r tubers (2, 4 ) During storage little potato es ca n deve lop eithe r on the sprouts or on the seed tubers the mselves (1) The aim of this inves tigation wa s to know whether little potatoes can be prod uced und er co ntro lled temperature cond itions so that they can be used as planting materia l The experiments were conducted at Centra l Potato Resea rch Sta tion, Modipuram . Five hund red seed tubers of six potato cu ltivars, viz Kufri Cha nd ramukhi , Kuf ri Jyoti, Kufr i Baha r, Kufr i Lalima , Kufri Badsha h and Kuf ri Sin dhuri were stored in cold sto re at 2-4°C from April to Se ptember, 1995 . The tubers were withd rawn from cold store on 18-9- 1995. The tubers were pre -sprou ted at room temperature for 30 days , des pro uted and stored at 20°C in a walk -in-chambe r on 19- 10-1995. Two more desprouti ngs were done at 30 da y Intervals . Deve lopmen t of little pota toes occu rred on 26 -12 -1995 . Two weeks before the devel­ opmen t of little potatoes , internal sprou ting was ob served in some tubers of Kufri Sind huri Interna l tube rs were als o observed in Kufri Sind huri during the second week of Februa ry, 1996 . In ano ther experiment, tub ers of Kufri Sindh uri and Kufri Lalima harvested in February were aged for 7 months at room tem pera­ ture either in dark or in diffuse d light and the aged tubers were shifted to GOC on '1 -10-1995. Obse rvations o n the development of little potatoes we re recorded on 12-1 2-1 995. When co ld stored tub ers were stored at 20°C afte r desproutinq , internal sprouting was observed In Kufri Smdhu ri upto an extent of ab out 1% (in six out of 500 tubers) . No internal sprouting was obs erved In the oth er five cu ltiva rs Figs 1 and 2 show that interna l sprou t growth in Kufri Sindhuri originated from an ey e w ith seve ral sprouts present in a cluster and grew into a tuber fo r about th ree cen timeters before it emerg ed o ut from a place w he re no other sprouts present. Internal sprouts are reported to ari se mostly from ax illary buds and pen etrate an intact periderm (3) Further penetration occurs du e to the sp litting action of the radial ex pan sion close to the tip of the sprout. Fig 1 shows that internal sprout had followed the path of least res istance and emerg ed at a place where there was no pre ssure of neighbou ring sprouts . Th ese possibilities can be precluded for the following reason s The apical sprout was not injured and the re wa s no mechanica l press ure fro m the nerqhbou rinq tubers because the tubers were sp read eve nly In the tray App arently , highe r temperature stora ge coup led with repeat ed desproutings has tened the develo p­ men t of Internal sp routing In Kufn Sindhu ri, w hich is susc ept ible to this disorder. Internal sprouting was not ob served In the other five cultivars Internal sprout growth IS reported to be cu ltiva r spec ific (5) . Damage to sprouts and pile pressure In the gun ny bags is also reported to ca use internal sprout growth (6) . Little pot atoes developed In all the six cu ltivars . Co nditions that accelerate physiological ageing of tubers such as repeat ed sp rout removal and prolonged storage under warm con ditions are reported to indu ce little potato fo rmat ion (4) In the sec ond experiment seed tubers of Kufri Sindh uri aged at room

temperature In dark were placed with and without sprouts at 6°C (Fig 3 A and B) and seed tubers of Kufri l.aurna aged at room temperature In dark (3C) and In diffused light (3D) were placed with sprouts at 6°C The results show that little potatoes were produced In all the cases Further, figure 3 shows that little pota toes formed can either be sessile (A) or weak thin sprouts (B) or healthy sprouts (e) or even at the trp of a healthy light grown sprout (D)

Fig 1 The up of an Internal sprout

In

Flg2 An exposed interna l sprout (measunng 3cm)

Kufri Sind hurl

Flg.3 Lit tle potatoes on aged tubers of Kufri Smd hun (A and B) and Kufn Lalima (C and 0)

The results of this Investigation clearly Indicate that the temperature can be employed as an useful too l for Inducing formation of the little potatoes on phys iologically old mother tubers under prolonged storage Kufrl Sindhuri was found to be susceptible for the development of Internal sprouts Literature cited 1

Bodlaender . KBA, C Lugt and J Marinus 1964 The Induction of second growth in potato tubers Eur Potato J 7 57-71 1989 The Potato Third edit ion, Longman, Singapore pp .742

2

Burton, WG

3

Davis. RM 1961 Ingrown sp routs in potato tubers factors accornpanymq their origin In Oruo Am. Potato J 38 411-13

4

Ezekie l, R 1997. Production of rrunitubers on physiolog ical ly old mother tubers of potato In storage In Proc Nat. Sem. Plant Physiology for Sustainable Agriculture . ISPP, IARI, New Delhi. pp.20

5

Sawyer , RL and SL Dallyn 1964 Internal sprouting of potatoes Am. Potato J. 41: 59-69 .

6 .

Tyagi , BR, PC Misra and HS Chauhan . 1981 . PhYSiologica l disorders leading to tuber formation inside the mother tuber in potato under prolonged storage. J InrJian Potato Assoc. 8: 151-54. 148