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.W .... ..
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... ... .. .... ...
M '. ......... ...w ........ .... ... ......
...: .. ... ... ..
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WM A ... ...... ... .. .. ....
... .... .....
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K! t 'Nifti 4z
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A k.o.. w
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tTO RICO AGRICULTURAL EXPERIMENT STATION,
D. W. MAY, Agronomist in Charge,
Mayagues, P. R.
BULLETIN No. 27.
Under the: supemriso of-the STATES RELATIONS SERVICE,
O' e of Experiment Stations, U. S. Department of Agriculture.
in:!.::. : "
...:.RE ..PORTO RICO.
CULTURE IN PORTO RICO.
.,.. ... 7.
.I.. .... ... .
i,i.;, ;;, .. .. .
C. F. KINMAN, Horticulturist.
Issued May 24, 1M.
. .:.'I : ... ..
. .:, ..... ...
|i| .;i ii ":x- .:
GOVERNMENT PRINTING OFFICE.
P i: :.:E .
-;;;;;; ;-~ii- -- --
:'..... .. .. .. .
; ,; :...,... ....
.l i' i. :" : "E :
i# a food crop in Porto Rico. 3 Tests of vine pruning ---_ -------- 10
lrctices in yam growing---- 4 Harvesting---------- ------------ 11
t of seed roots--- ------- 6 Varieties and cultural treatments
Sart r to plant ..------. -- 7 recommended ------------------ 11
fertiliers.------- __.-- 8 Conclusions--------------------- 21
S THE YAM AS A FOOD- CROP IN PORTO RICO.
Syam is one of the important foods of Porto Rico, and among
rot crops is second in this respect only to the yautia. The quan-
S~osmed is far greater than of either the Irish potato or the
t~ato. It is found in nearly every family garden in Porto Rico,
i is well adapted to most soils of the island and is almost en-
e from destructive insect pests and plant diseases. Notwith-
iits importance and wide local distribution, very little has
n regarding its culture, at least so far as this has a bear-
SAThe agricultural conditions of Porto Rico. Planters are so
i obtaining a fair yield that they have developed to a large
-. tendency to be content with a moderate crop from a mod-
Boutlay. Practically the entire production is for home con-
i the great increase in price of all food products, the yam,
A still among the least expensive of the food crops, is more
nd than formerly. Yet, despite the fact that high prices for
hive prevailed and the local consumption of the yam has been
. i ijai ted, its use in other countries has increased but little. If
ophrly handled however, it might be shipped to other markets
little fear of loss by deterioration. In the continental United
0 e4s thi yam is rarely purchased by any other than people from
Si Tropics, and it is still practically unknown. In the Southern
te the. name "yam is, commonly applied to a certain type of
potato, which, however, is a different plant. The high food
fi he yam, due mainly to its very large starch content, the
k.. sys in which it can be prepared for the table, and its low
i:.shop|ld serve greatly to stimulate extension of its use.
I ...A i .
-IkindaL Of 'Yftnjt_
folio ed. hey
ycla and give
--y'Vaeties m P0
-,,arp, sufficiently high t4
ac*d and ou
W46, '& root 4
of Jimsthc I ti $64
of the M
pljjjtff 't t'41 -A -4
T6 tiin, to" Paut in
prvba*,4h r6"m 114 c
Od -m&t rr
crop len M 0
and winter 'and I""
wAout, fear-'4 Ae(OdQrafioi
through a Img perW i
pending upon t6 f "I
.AM CULTURE IN PORTO RICO.
succeeding crop may be left in the soil until planting time
lowing spring. In this way good seed may be preserved from
SClean seed is an important factor in establishing a good
.. of new plants. Should a drought follow planting, the root
ions, if they are free from decay, will remain in good condition
nany weeks, owing to the thick corky covering of the yam,
s ables the seed pieces to retain for a long time sufficient
or the growth of the plant.
ough very resistant to severe drought, requires a heavy
ir its best production. The plant does not have an ex-
6 system, nor roots that work deep into the earth, yet it
eiient moisture to carry it through long rainless periods.
f... rved along the southern and western parts of Porto
Ilr : the vines make a moderate growth and show no effect
tdght which injures other vegetation.
rparing the land for planting care should be taken to
t. i -oil. into good mechanical condition. Substantial ridges
S -~1s would be made, to protect against excessive soil moisture
.. secure good aeration of the soil. An excess of water in the
b labty results in a crop of poorly developed roots. The
varieties when grown in heavy unloosened soil are rather
& irregular in shape, and the production is small.
Such results, ridges of loose earth and vegetable matter
e4~ constructed from 1 to 1i feet high, depending upon the
d the subsoil drainage. These ridges should be made
gthe land deeply and thoroughly and by opening a wide
*over Which the ridge is to be made. In this furrow a few
h t dead vegetable matter should be placed and covered with
inehei s k of earth. This should be followed by another layer
*kitable matter, the layering being continued thus until the
4~ tfnished. As the vegetable matter decays it causes-a set-
re earth. The beds should, therefore, be made a few inches
Bi otherwise would be necessary for the growth of the
i:' ridges .may be cheaply constructed with a plow, the
r diid labor :needed being in the application of the vegetable
i:and the final rounding up of the ridge with hoes. The
of manure or other vegetable matter in the ridges insure a
, will-aerated medium for the development of the roots, and
" iE"be required for their best development. ~ The ridges do not
bie large in sand or sandy loam unless the subdrainage causes
Li tiot' of the strata occupied by the roots. In these soils
wE.* %roviding material should never be omitted.
hme seed i scarBce either crowns or entire small tubers may be
esf .lly used, or a cross section of a slender, cylindrical root
of th6 iibat
Tho lower pa
4A. upperpWrt 4a]Aa 40'
Mhe "Operimm AaV
crownmid.,,P ji* 044
,pd j4o oe, (W, lo,
(W, tw 0 'r04 is I
tion with &ITereut sizpd pjg,m
tir u bm of somo pf he jsr'ajI4*XDW,,
g,*m M, YOM V woo Py lus)'P. g,.,
TRFATMP," OV SIM'R,00".
4 ,of Plauts are U sIV,
depayii* 16`46 vine gri
re the cn4l Oa
were givep. n 9f -see# piece$
the ntiame 6f vh
The' cut surla
those of anooirlotw4i.,
were tre6ted with,1346_1
cut and the offier after,
lot was Placed t6 0
. . . .............
a a WAM J LFd66 aAva%#% .
ill-rooted type of the Potato variety and a large-rooted kind
SSt. Vincent were used in this test. The yams were harvested
ys before treatment, and after treatment were stored in a
having a high humidity and temperature of probably 800 F.
oh conditions favor the rapid decay of the roots.
4wo weeks after the treatment was applied the roots were exam-
i. wias found that where the lime had been applied 40 per
pieces were decayed, although none of them was entirely
Where Bordeaux mixture was applied to freshly cut
nly 16 per cent of the pieces showed decay, and all could
dThe application of Bordeaux mixture to the lot that had
i sly dried resulted in little improvement over the check.
ated lot more than three-fourths of the pieces were con-
impaired and a few were entirely consumed by disease,
only 12 per cent were in normal condition. In all cases a per-
4..-of the decay on the cut surfaces developed from bruises on
f ; jarts- of the roots, and in some instances from infections re-
p after the roots were cut. The Potato variety was slightly less
hed than the St. Vincent.
DISTANCE APART TO PLANT.
.ti:.stance between the seed yams in planting depends much
'ti normal growth of the variety. One foot apart in the ridges
a t for varieties producing small roots, but the larger-
~Si inds require a distance of 1 to 2 feet. In Porto Rico it is the
ice td" plant much farther apart than this, sometimes twice the
i~e:. This is hardly wise, because a given area will produce
it nWore when close planting is practiced. The cost will be lower,
~ince the only cultivation required after planting is occasional
Ming and maintaining well-formed ridges. The expense involved
Iiiation consists mainly in plowing the land, securing suitable
. manitter or manure for the ridges, building the ridges, and
iig p.le .f1or the support of the vines. Any decrease in area
riFd': ibr planting results in a proportional decrease in expense,
ly' good preparation being necessary for planting at any distance.
fiE hill planting is practiced the hills should be from 3 to 4 feet
:t each way, depending upon the type of soil. The wider dis-
is "is necessary in heavy soils because the hills must be made
er than in more open soil to insure good aeration and drainage.
i slrest planting will be found convenient in light soils. The seed
i, ecovered with 2 or 3 inches of earth to prevent it from
Ag in ease drought follows, or frbm being washed out by heavy
.......... .................. 46|
Illmmloamm ba If
d hc- I
4 ..... .I ... .
I P Ji A
":i .i ii :!... ... .. 1 ;
..f.1..k k.f l j...
--I-------- -- ......
--n u siH; V.
i ... .r.... .. ..rr. ...r
l.ilkt~Jo brii ..Jt U
. .'. .i r f t. .....
I, i k o 7 7
a:.-'j t-i 1w" t
' i.w mhj. ae lied.
*' A ^ i
I *.ad .
kait o+i:::h:.. Pod. Excof- "*
m ponds per AMZ, *Me plawtja, of four vorie. ies 0
,. Hifedze4 and, 'f ertfl pdi pat4, driLfg ae years named
1 ., **E 5* Ii.;
't; CI aiCr 2:.8 2.2 1 ~2.91 3.95 2.75
8.4 7.4 65 41 7 4.8
:7, *5 & A.4 7 5.9
4.8 4,45 5. 5 6.36 5.5 4
S* *" ''' : ---. -.._-.-
-..3 3 : .9 ..6.5 9
, I ^ !S ^ii2 t ga 4.8 3.33
- .6 .4 .1 2.1 1.1 1.7
P. 6 04- -10."4 T. T
..' i W', l .( ,sj .)(i- 'b += .t ;nu
. 43.37 4 4 4.2., 4.62 4
2.2 .4. ,3 3 4.6 3.3
n;'lIfZ:il:;': 4 'Sa 14 .7', '3.b5 "-1.9
.^.ijt~- i ^T-'^ ^^ ^ ^';a' A.
:, j, A: i Nadhplat wqas about lie-twentieth acre ip size.
.. .. .. .
lsbb diias thai thoe w ja wide range in yield of each
jS the iif-rent+platks dWurig i gienl year and that large dif-
r i4~ nt. kiftOtCdldii Iallhepliiting ~a lso that the dif-
b hflir p'rodued oniy Arall differencess l the average yield
aIddi o6-fio'ps., Whae4'r all three 4h emiica! -ingredients were
I tilerkge 'prodnetio ifor tall ramietie& combined was consid-
V[thtanu irfe r .eOeflmeht -wrasr' omitted. It was also
Ilicrrn it led4 tiearte its given ii all, exept the Barba-
[W:leithli th el ,ie'roit0 btblrm-nan slightly exceeded
Wew i tkiteeliuen.tpstrWaigiwiven,: thhplat niade a gain of
lWIps!5oprrpetpfrtvivet iekmx Inlih test where nitrogen
aitl mlad inrltht ,whep~aPp la wae-omitted, the. total
Wse jiiwem saugr lessithuwhiafts febAiliers 'ere given. The
gisi vib tg tn al BeIlarledie(cdimbihedi average produce
Sny other plat except the one receiving no phosphorut:ish:
mined aveAfhb liluWd It~aY thlgit treated with stable
Oater than that of any other plit except th one re
&ewF v ;atwifi k4lit ddied b cdfnt.
D~j~I~i'i Is 4,19 1,
, e s 0#
1 I I r I
1 l( it i .l ) CIA4
41f 4 1 4-1
Qfl'lrr? CULTUREr INge POR ttO'i
ooted kinds. The ridges' for planting were' made in
l,*iy and in soil that was well adapted to the crop. The
made thrifty growth and were pruned back each week, the
.,to 6 feet and the Potato variety in one plat to 2 feet, in an-
.ito 4 feet, and in a third to 6 feet. Plats of each variety were
awe~&ifor checks. The vines of the Potato variety continued
the season, but the pruned vines of the Guinea
ofme ; of their rich color before fall and became dry
e earlieri than. the cheek plat. The harvest from the
ia the variety Guinea was only 46 per cent of the yield
the cv heckl plat. The yield from the Potato variety
8qtjI o~em the vines pruned to 2 feet, and 46 per cent
id to: 4 feet, while the yield from plants pruned to
I r cent of that obtained from the check plat.
id shows that the vines should not be pruned or injured
result are expected. Where the vine supports were in-
Si.aellowed to blow over and were not promptly replaced,
iasl a marked decrease from- the normal yield. Vines not pro-
iS. sith t.spports, but allowed to creep over the ground, made
oouw growth and gave low yields of roots.
.&i Mlalemnts~ as mattocks, heavy forks, and spades are required
e~hdtirg yams, becaUfiethe earth must be removed to the depth
bm as. T. he large roots fit rmly:in the soil and it requires great
;~ remove them without injuring them. They will be bruised if
B~r~ pried out beforeth-e soil around them is well loosened or
e~t:ij The process of digging deep-rooted types in heavy soils is
atZj n dry weather, because the roots are often enlarged near the
rm:ed and are easily injured during removal from the hard soil.
Safilli varieties of yams are subject to rapid decay if they are
hqtdtithe skti is broken. When bruised to any depth they soon
il Aittei I use.: Tah yam, like the potato, is used while it is
h~5~ryi precaution should be taken to keep it from decay-
ti~ialthent ire crop ean be;utilized.
I CU RAL TREATMENTS RECOMMENDED.
md*theif6Wing arexsind welkn6Imow varieties that have been
f y ~is J fot hom' and market codnsumption in every part of
i&eb. ISo:Eee others mentioned are not as yet well known, haI-
SIeent~ly been introduced into the island, 'ad probably into
i.B~lie .: A. wamber of the latter varieties have desirable
i.y -arete bitardered among the best in flavor and qu.ality.
Stital i. l~parts of the island. The varieties discussed in
IA I L II L
Bul. 27, Porto Rico Agr. Expt. Station.
FIG. I.-VARIETY TEST OF YAMS, RIDGE CULTURE, PORTO RICO STATION.
FIG. 2.-SPECIMENS OF GUINEA YAMS (DIOSCOREA SATIVA).
~p: c,. s r
r : I-- ~
-h ?jf:25 dP: .1.
Bul. 27, Porto.Bico Agr. Expt. Station.
.. .~i, -_ ;..
POTATO YAMS; WEIGHT, 12.5 POUNDS.
FIG. 2.-POTATO YAMS; LARGE VERSUS SMALL SEED TUBERS. PILE ON RIGHT,
SEED WEIGHED 135 GRAMS; ON LEFT, 45 GRAMS.
i|l C. E4lu fUA... i 1b %A5IJ UADA LLjL t lLu LULd @II UVO U
Ta.i.ti .6w of th city markets of Porto Rico it
ipri;.:! Te e Potato yam should be planted in all
j.i.exi: where the soil is light and sandy. It will
fhi:.riiety:Are slendt, round, of moderate growth,
tlier in the dry eason of winter than any other
iv miriety known as Congo, the vines of which grow
.i Jo o zen Iapore rshlort, strong, sharp spines
of plderg parts of .her vipe, The leaf petiole
.a few ,spes reseh"li-g: those on: the vine,
rJ0: MPu hafp 8PiTP04 Tbi hIeayeq appear alter-
""9" op "jith crown, of the plant much
I.Je M 9Ya land varyup to 8 inches .in
diameter. As they a~ pmals ad ,not easily
Ake41P r afterbeiung4 hvnested4
..la4.i.ly q 9 I pitake. for the Irish
t..~g. p4ldP4ay, pgferthingbroken, -
L*at14wp ep1si 9perryJ1ark. The
e k sty""~t~arph4t iswhite, brittle, uand
ti iif whU x iPowiA to remain too
fiAaii va Jai. f in the soil til lat
bi. .w. JwHg- a n rather strong, longi-
nir~s!4 r:,t ae fie-gr wed, tender. and
SaPIO M pM rface soil and are not hi-,
Ssoil tt.e tto tiy "y ha";.ves. best in rich
$jfli...f d, leay~ This vsriety
b,.g "".~~ nguhlar. or flattened tubers
i.':irS 0h *;wnW'd1, for, planting should be
......4...AD4. pgot vsult tion will be.unneces
waial* 'pg 4 p hiOiplant's li-fe.L
^niv ; zee :t ;..1k* made to d.tej ,
at rge~a mn B Jsa,0ot1 o4 the Potateo variety at
klastheresl ield of plaatipg oo e
^ ^iIfl t4 'lrtb.Bpl*A0 gwo.h -qqts sI^j^it-y 4 f
t E E="" ":.
Aii 1& livi,,i"
' h:AW:. J,,IULaPqE =:'1 PORTO RICO,
ti ie t a good depth, or on low ridges. As a
p, tiep lxad iq prepared more quickly and at less expense
S. .. : -. : TOIGO.
.I T ... ... ." : .:: :* : f ":'- *-
d aiei(y (Pi IV, fig. 2) was sent to the Porto Rico experi-
fii 1915 fu m No Guines through the Bureau of Plant
IiUted States Department of Agriculture. It was known
Sio.1SS1^ and wa identified by P J. J. Wester2 as Dioacorea
csIfly known as the Tongo. It has proved so satisfactory
rrecommendation as a very promising yam for Porto
so closely resembles the variety called Potato that
idil~y be distinguished by the casual observer. How-
Sav. are somewhat larger and slightly different in form.
of both is light green and does not become dry until late
.r sao. Neither of thee varieties produces as heavy a
as most other kinds. Each variety sends out a number
n s ins that are 1 to 4 fee long. They are found near
i the ground. These stems are set with long, sharp
Shicam a hindrance at harvest time
a fertile loom soil although good crops were
ma heavy clay at the station. Since the roots of this
Aj grow as deep as those of some other varieties, low
ulicimnt to enable them to attain normal development.
were made at the 1916 harvest to determine the relation
tI er. p ucd to the size of the tubers planted.
t th ubers obtained from the 235 plants grown
u IWtuheis were on the average 17 per cent larger than
fn an eual number of plants grown from small
tidible roots are larger than the Potato yam, but are
i" ared e t largest rooted yams. They are produced
eame a sweet.potatoes The roots vary in size from
to be of ae for table use to 10 inches in length and
SThey are smooth, except for numerous short
t ~ These are grayish-brown and much more
half of the root. : The skin is very thin and
iPotto yam." However, it is not as tough and
"from the inner part of the root as is the
.'... ya "The edible part of the root retains its
ifte being cooked, has an agreeable texture, is very
Sd sweet and rich in flavor.
weighing about 4 ounces gave best results in tests
.BI.u. .X':oi ... twice this size made a slightly greater yield.
hut a 2 ones yielded almost 40 per cent les than for
iiiiii iiii1.1 0)ii ......... p.
.i ..... .." .. .
Bul. 27, Porto Rico Agr. Expt. Station.
FIG. I.-RIDGES 6 FEET APART. PLANTS I TO 2 FEET IN RIDGES.
FIG. 2.-HILL PLANTING 2 BY 2 FEET APART.
POTATO YAMS; RIDGE VERSUS HILL PLANTING.
Bul. 27, Porto Rico Agr. Expt. Station.
-: .'. ,. !'
." '.. i ; .'! ":..
FIG. I.-RESULT OF EXPERIMENT
PILE ON RIGHT, 4 BY
IN SPACING PLANTINGS OF POTATO YAMS.
4 FEET; ON LEFT, 2 BY 2 FEET.
FIG. 2.-A HILL OF TONGO YAMS (DIOSCOREA ACULEATA), S. P. I. No. 31923.
: ;;;;;; :iiiiiiiiiiiii3Eiii
; :" .p. EJ
; .(.. c~Ln~
;.,, r *j~-;z~E~
develop on the vines of this variety. The edible root is
zieal or made up of two or three large round lobes. How-
koteir forms long, deep-growing roots. Usually a slight
iJ curs at the union with the rootstock. The surface of
li'roumgh, corky, and dark gray. The interior is a rich
d has some areas where the coloring is not so intense. The
itefent in the fresh root is 20.03 per cent. After being cooked,
haI. a smooth, even texture and retains its dark purple color,
H it to resemble the well-known variety locally known as
brado. Its flavor is rich and pleasing and has been highly
"eitd by all who tested it.- Unfortunately, the distribution-
i le Ceyl~ as well as the area planted to it, has been some-
is. Its edible qualities cause the entire crop to be con-
ite year, and the result is that only the rootstock is
brown at the station as S. P. I. No. 31922 has been iden-
iram specimens sent from here, by W. E. Safford, of the
^kof Plant Industry, United States Department of Agriculture,
of D. sativa This variety, originally from New Guinea,
the varieties tested the only one that produces vine tubers,
potatoes" of sufficient size to be suitable for table use. Its
S;be is suiliciently high to justify its being planted more
:The, vitnes of this yam are large and make rampant
tnlei r, normal field conditions they sometimes attain a
fe,:25 .et. The leaves appear opposite on the vine and have
i,.sl e round petioles that are 5 or 6 inches long. The blades
iua.44 to 6 inches in width and from 6 to 7 inches long. Near
ewdpf the petiole there is a purplish section which is from } to
a long and considerably larger than the remainder. The edible
are irregular in shape and usually develop from the rather long
,four to eight finger-like lobes, some of which are divided
The whole roots weigh only 1 or 2 pounds. (P. V,
iTe skin is ery thin and tough, and would be smooth were
S rous s rootlets. The inner part of the skin and
i........... : i.. ... ......
ib 0 ip
WOW Vr- Z. 7Z liifr m
riak-t vapogi Ow I bm* 4'0=5; iw*"Po,
lit Mik 1 .411.141,
ot wffft, f wo
k ijW, q
to be Jai urvd 'ut
content, of the ",,air t4
A,.tkPt P-0 t_Xf*
tt 1 f'
e 4 4'' 1 cl, f 4A Intro
tin liv*,48-somp Olt or
Mended trittl JA
aged over 5 polindsptior''
weigh-ing twice lhio
iobes. The roo
of the echibli 4on is
ish col6r, hdie ei, gm'"ifti
YAM CULTURE IN PORTO RICO. 19
the lobes are very tender and almost pure white. The skin
Lu paper portion is rough and corky; on the lower portion it is
easily broken. The roots are susceptible to injury at harvest
--because they develop well below the surface of the ground, have
e interiors, and are large and oddly shaped. So that harvesting
e:. ilitated with least possible injury to the roots, banks should
:as high as those required for the longer-rooted kinds. In-
o .s decay much more rapidly than those of most varieties,
ue1 d specimens retain their tenderness and good texture as
ul!ky j other large-rooted kinds. Upper sections of the root-
Ien vplanlted simultaneously with equal-sized pieces from the
pr.t fthe root, made an average yield per plant which was
:the same for the Aifferent plats. It would therefore seem
r -favorable conditions any part of this yam can be used for
6 Spanish name Agua, meaning water, is given to a number of
eis of Dioscorea alata, and is used to indicate one particu-
ype of yam that is probably more widely known than any
i. Porto Rico, but which is usually ranked as a second-
i". "Its popularity is in great measure due no doubt to its
H,..yield on a wide range of soils and to its peculiar keeping
after being removed from the ground a long time. The
fi the Agua are moderate growers and four-sided, having
;wide membranous wings running along their corners. The
of these wings, like the margins of the leaves, are purplish.
a blade is normally 4 or 5 inches long, and 34 or 4 inches wide,
t~~te petiole is about 5 inches long. The large cylindrical or
ii' ots are very dark, rough, and thick-skinned. While the
00w yer of the skin is tender, the inner yellow layer is exceedingly
interior of the root has at the base a marked brownish
hich decreases toward the lower end. When boiled, the root
i a lightly yellowish watery color. The edible portion contains
c:.nderable fiber, but otherwise the texture is of good quality.
;i',tis variety sells at a lower price than most yams, because it lacks
4 richflavor found in other varieties. Like all other large-rooted
I dfieties, it should be planted on high ridges. In Porto Rico the
seems general that to produce roots of marketable size, either
S.own or top of the old root should be planted. Experience has
..however, that almost identical results can be obtained from
-J bottom sections when planted in well-prepared banks.
Sstach content of this variety was found to be 16.76 per cent
e fresh, yam. This is considerably below the average for all
4c 19. ,i 4 j 14
e tf ttt
#Idn ig t
'a-verage a, P
Bul. 27, Porto Rico Agr. Expt. Station.
FIG. I.-EDIBLE ROOTS AND AIR TUBERS OF YAM (DIOSCOREA
SATIVA VAR.), S. P. I. NO. 31922.
FIG. 2.-SPECIMEN OF YAM (DIOSCOREA CHONDROCARPA), S. P. I. NO. 31920.
Bul. 27, Porto Rico Agr. Expt. Station. PLATE VI.
FIG. I.-SPECIMENS OF YAM (DIOSCOREA ALATA), S. P. I. NO. 31919.
FIG. 2.-SPECIMEN OF YAM (DIOSCOREA ALATA). S. P. I. No. 34861.
pey morado is a variety well known throughout Porto
it is considered superior in flavor to any other yam. Its
..per hill, however, is so low, unless the plant is grown
iost favorable conditions, that only a small area of land
ito it. It succeeds best on a very fertile, well-drained, and
y prepared upland. In such places it yields sufficiently well
table, because it always sells at a considerably higher price
.i. ds. The club-shaped roots of this variety develop in
: surface of the soil much the same as sweet potatoes,
to eight roots growing in a hill. The roots are 3 to
ii 'to 8 inches in their greatest diameter, and for more
.ir length taper toward the slender rootstock. The
hand corky over the rootstock and basal portion, but
teud.er over the remainder. The interior is solid, brittle,
pu ~e color, and contains 23.17 per cent starch in the fresh
When cooked these roots are of first-class texture, and
"pleasing flavor. The roots of this variety, being small, keep
Since they develop near the surface of the ground they can be
t injuring them.
yar, which is nonresistant to frost, thrives well in Porto Rico,
ere the climatic conditions favor its growth. It is one of the most
prtant root crops of the island and one of the lowest-priced foods.
grown in family gardens in all parts of Porto Rico because it is
daPted to many soil types. Practically the entire crop is grown
of well-stirred soil and vegetable matter should be made
y large when planting to enable the roots to make a normal
above the water level in the soil and above the firm subsoil.
ts should be placed from 1 to 2 feet apart in these ridges,
to conditions peculiar to the root growth of each variety.
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