xt751c1tg76t https://exploreuk.uky.edu/dips/xt751c1tg76t/data/mets.xml   Kentucky Agricultural Experiment Station. 1939 journals kaes_circulars_003_336 English Lexington : The Service, 1913-1958. Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Circular (Kentucky Agricultural Experiment Station) n. 336 text Circular (Kentucky Agricultural Experiment Station) n. 336 1939 2014 true xt751c1tg76t section xt751c1tg76t 9   I
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1 Lessons on F arm Crops i  
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CIRCULAR NO. 336 “ ,    
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[ UNIVERSITY OF KENTUCKY I  
 s COLLEGE OF AGRICULTURE  
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 . Extension Division   {
  THOMAS P. COOPER, Dean and Director    
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 i Lexington, Ky.   F,’ 15
Q  June, 1939 “  
 Q Published in connection with the agricultural extension work carried on by  
 Q €¤¤D€F¤t10n of the College of Agriculture, University of Kentucky, with the U. S.  
 ` Pevartmcnt Of Agriculture, and distributed in furtherance of the work provided fur  
 § ln the Act of Congress of May 8, 1914.  
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. [ PREFACE
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.— 1 These lessons are intended for the use of stud1 rou s 111 4-H
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I   and other agricultural clubs in Kentucky. As a rule, such groups
    meet but once a week, and each lesson, with a few exceptions, is j
l tl intended as a weekl 1 stud 1 assi nment. However, it ma 1 be desir- J‘ 
, _._ l l 8 l Z
f _f W; able to spend more time on the study of certain crops — tobacco, for ·
§   example — in which the group is particularly interested, and less T
i,   time on crops not important in the community. It is usually im  1
  _   possible to cover the lessons fully at the weekly meetings, and the 1
E. jj leader should go over each lesson carefully in advance and select T
  for discussion the most important points. ‘
E. -v i This edition 11as been revised and made more complete than 1` 
H Y I . . . . . .  1
  previous editions. Considerable information on plants and plant
  activities has been added Lesson l . This is information that 4-H
  . l ... 
  I club members should have, especially those interested in plant ,
Y;   breedin · or the rod11cti0n of farm seeds. For ’OLll]¤`€I` `rou as of 1
P`; L 8 P l ¤ S I ,
tz  g students the more difficult portions of the lesson 1nay be omitted. T
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  The lessons on tobacco should be particularly useful because this =
  cro > is not disc11ssed full 1 in most textbooks on cro s. ’
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Lesson I. Importance of plants. Variety in plants. Photosynthesis.   .
L The growth of plants. Species and varieties. Botanical classification.   ~
~ Plant names. Annual, biennial and perennial plants. Reproduction in l *
Seed plants. Self pollination and cross pollination in plants. How plant A    
chal·aetel·s are transmitted. Questions. ..................................................,............_ 5 `   Q
Lesson II. Beginning of plant culture. History of crop plants. Crop   P
improvement. Introduced crops. Crops of the United States. Production F l
V statistics of important crops in the United States and world production. ` E.  
Questions. ........................................................................................................................ 15 1 . `    
{H  . conn   V   §
U ls I Lesson III. Importance of corn in the United States. The corn plant. I  
IQ   suckers or tillers. The root. The leaves. The flowers. The corn ear. ` , I l
I 15  ‘ classification of corn. Varieties of corn. Questions. ...................................... 24 V ~ q l
rslr-     J ‘ 3
{Or _` Lesson IV. Climate and soils for corn. Rotation of crops. Fertili- . |  
; zers. Varieties for Kentucky. Corn breeding and hybrid corn. Impor- ~ ‘ '  
l€$$ Q tance of a good stand. Care of seed. Testing germination. Shelling and ,  
ima  L grading seed corn. Questions. .................................................................................. 31   , -V  
.; , (
the   Lesson V. Plowing. Planting. Cultivation. Harvesting. Questions. 44 ‘ ”  
tec:  Q . J
  TOBACCO S f.````  
lan VZ  Lesson VI. Introduction to the studv of tobacco. Origin of tobacco . . {  
am   and early history. American types of tobacco. Fire—cured types. Dark g r ·*
[H  { air-cured types. White Burley tobacco, Other types. Amounts of types !· ' 1
`   grown in Kentucky. Questions. .............................................................................. 48 `   Q
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Of _‘  Lesson VII. Soil and soil management for tobacco. Fertilizing , i yi
d  - tobacco. Raising the plants. Preparation of land. Transplanting. Culti- .    
C ‘ ‘ vation. Topping and suckering. Questions. .................................................... 60 ‘ ig;
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  Lesson VIII. Harvesting tobacco. Curing. Stripping and sorting. `    
 _ Marketing. Questions. ............................................................................................ 66 ] p T  
  Lesson IX. Rehandling tobacco. Raising seed. Insect pests. Tobacco  
  diseases, Questions. ........................................................................................ 76 `  
 I THE POTATO I  
 ` Lesson X. Importance and production. Description. Varieties. Soils, .  
  fertilizers and rotations. Applying fertilizers. Planting. Cultivation.  
  Diseases. Insects. Harvesting and storing. Questions. .................................. B6  
 ‘ };,  
 ; COTTON  
  Lesson XI. The importance of cotton. The cotton plant. History and    
Q;  ¤§€S of cotton. Soil and climatic requirements. Production methods.  
RE  Picking. ginning and ballng. Insects and diseases. Production figures.  
 i QUESUOHS. ............................. . ......,............,..,..........,.......................... . ........................... 94  
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_ _ rl THE SMALL GRAINS
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  Y Lesson XII. The value of wheat. Wheat crop of the world. Wheat »
5   in the United States. Kentucky’s wheat crop. Spring and winter wheat.
E " :5; The wheat plant. Gluten. Questions ................................................................ 102 °
7 (
i   ‘`._   Lesson XIII. Kinds of wheat. Varieties of wheat. Seed wheat. Pre-
  Q ~ al paring the seed bed. Fertilizers. Seeding. Harvesting. Diseases of wheat. r
  ji Insects. Questions. ...................................................................................................... 106
;— {J
  Wl Oats 4
?~   Lesson XIV. History and adaptation. Oats in Kentucky. The oat
   ___i plant. Varieties of oats. Uses of oats and oat straw. Soil requirements. `
L. f [ Preparing the seed bed. Time and rate of seeding. Harvesting and
i *2 gi threshing. Diseases and insect pests. Questions. ............................................ 112
¥PQx“i Rye ' 
t·_C-Q7 Lesson XV. Production. Rye and wheat compared. Uses. Rye in
K   _
  fl Kentucky. Varieties. Seeding practices. Questions. .................................... 118
Q   Barley and Buckwheat ;
  Lesson XVI. Barley: history and characteristics. Production and
i   uses. Varieties. Soils. Advantages and disadvantages of barley for Ken-  .
[-,   tucky. Cultural methods. Diseases and insects. Buckwheat: Importance g
if`- and uses. Culture. Questions. ................................................................................ 123 Y
LQ   HAY AND PASTURE CROPS {
; `»*,   Lesson XVII. Alfalfa in America. History. Where alfalfa can be  .
;_   grown. Varieties. The alfalfa plant. Flowers and seeds. Soils. Starting  
‘j.  YQ the crop. Inoculation. Cutting and curing. Cultivation. Alfalfa and soil ·
E _;_ improvement. Questions. ................................i......................................................... 130 _·
  Lesson XVIII. Red clover: Importance and adaptations. Varieties. _:
  Strains of common red clover. Seeding. Pasturing and clipping young
  ST clover. Making clover hay. The seed crop. Alsike clover. White clover. '
    Crimson clover. Questions. ...................................................................................... 138  `
  SWVEET CLOVER, LESPEDEZA AND VETCH
  Lesson XIX. Sweet clover: Description. Adaptation and uses. Lime  T
  and phosphate for sweet clover. Seeding. Inoculation. Pasturing sweet
  clover. Sweet clover for hay. Saving the seed. The lespedezas. Varieties. · ‘
  Importance and uses. Seed and seeding. Seed production. Hay. Vetch.
  ~ Questions. .................................................................................................................... 145 ‘
  SOYBEANS AND COWPEAS `
  Lesson XX. Soybeans: History and description. Uses. Importance.
  Climatic and soil adaptations. Varieties. Land preparation. Inocula-
  tion. Seeding. Cultivation. Stage of maturity for harvesting. Curing
  soybean hay. Producing soybean seed. Fertilizing. Cowpeas: Impor- ‘
  tance and adaptation. Varieties. Culture. Questions. ................................ 154  ·
  rm: GRASSES  e
  Lesson XXI. Important grasses for America. Timothy. Kentucky
  bluegrass. Orchard grass. Redtop. Bermuda and Johnson grass. Sudan __
  i grass. Pastures and pasture management for Kentucky. Questions ....   164 ;
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Circular N0. 336 i ·
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LESSONS ON FARM CROPS FOR 4-H CLUB MEMBERS  
By E. J. KINNEY   {  
106 { M    
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_ 1 LEssoN 1    
° The Importance of Plants. Man is entirely dependent upon y . '   »» 
. plant life for his food supply. His diet consists partly of animal . y    
H2 P )y()(lii(;[$ but the animals which furnish these nroducts feed on ` Y l  
i 1 . . . I 1
5 plants or on other an11nals which subsist on plants. Plants are not T  
H8  j only the primary source of our food but, directly or indirectly, they y A  
· furnish most of our clothing and the fuel necessary to warm our 5 }  
% houses, cook our food and develop power. Much of t11e material · i
 ; from which houses and other buildings are constructed and from i  
f which thousands of articles indispensable to civilized people are - 1 I-Z.; 
123  T- made, are products of plant life. Clearly ll12ll'1,S existence would be  `gg
 s very brief indeed if plants were to suddenly disappear from the ,  
 ?‘ earth.   A j
’·  Variety in Plants. Plant life is exceedingly varied. There are ’ l   Ji
130   thousands of forms so small that individual plants can be seen only   · ;
Q by the aid of powerful microscopes. At the other extreme are the y y l -4
  great trees of the forest. Between the two extremes there is endless    
  variation in size and structure. Plants differ not only in size and .  
138  » structure but in the kind of food the are able to use. Those which T if 
 t . . Y . .  
 _ contain chlorophyll, the green pigment which gives leaves and t pl
Q stems or other plant parts their green color, obtain their food from    
V- simple chemical compounds taken from the air and soil. From T E .»___.  
1 these simple compounds are manufactured the complex compounds F Vilv E
145 Q —the foods—necessar* to sustain life. Tl1e other rou of Jlants Y  
I _ l S P l .  
g consists of those which lack chloro >h tll and as a result are unable   P
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3 to manufacture food. They are either parasites dependent upon  
c livin· ulants for their food snail * or sa Jro h ttes which obtain y lin
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. their food only from products of plants and animals. Some utilize  
154   both sources. Among parasites are the rusts and sniuts of grain  
 _ crops, mildews, the bli hts and wilts affecting various cro s and  
_ g 0 P  
ji  hlilldreds of other organisms which cause disease in plants afld  
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164   ' This circular is intended to take the place of Kentucky Extension Circular 56, Less0¤S `  
·;_  on Farm Crops. I.;
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    6 Kentucky Extension Circular N0. 336 °
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Q   animals. The best known of the saprophytes are the common toad.
    stools, and the yeasts. In addition are the numerous kinds of bac.
    teria decomposing organic matter. The latter are of great value for
  T.   as a result of decomposition by different forms there are produced
l_   finally the simple nitrogen and mineral compounds which are the V
  Y   food of the chlorophyll—forming plants. _
) ,. `   ·Photosynthesis. The- staple food from which green plants 4
E ‘ 1 build their tissues and obtain energy for the plant activities 1S starch.
E —`   Starch is manufactured in the leaves or other green parts of the
  *1 plant as a result of a process known as photosynthesis, which means
  ‘`__.°   "building with the aid of light." The materials from which starch
  is made are carbon dioxide (CO2), a compound of 12 parts (l atom)  
    of carbon with S2 parts (2 atoms) of oxygen, and water (H20), 1
) (fi ) which is composed of two parts (2 atoms) of hydrogen and 16 parts .
p   (l atom) of oxygen. The carbon dioxide which is present in small l
l “) amount in the air enters the leaves thru tiny openings known as L
P -—’r   stomata. In the plant cells the carbon is united with the hydrogen
tf;   and oxygen of WEit€1` to form starch. The energy necessary to bring ,
ff  about this chemical change is the energy of light. The chlorophyll _
)   ) enables the plant cells to use this energy. It is important to remern- ~
  _ ‘)) ber that photosynthesis takes place only in the presence of light and T
    only in plants supplied with chlorophyll. V
li V _ . I The Growth of Plants.* As explained, the starch manufactured ;
  in the leaves is the all-important building material of plants. How- ,
  Q ever, it is insoluble, and only soluble material can be transferred to T
    i the various parts of the plant where it is needed. Plants have the  
  · remarkable ability, however, of changing starch into sugar and other
  related materials and back again into starch. Since sugar is soluble, i
f  _ it is easily transferred and is used as the basic material for building
)   ( the other compounds produced by the plant—cellulose, protein, fats,
  and mineral compounds. Proteincompounds contain sulfur and _,
  s nitrogen taken from the soil, and the mineral compounds also com€
  from the soil. All the food manufactured from the simple com-
  pounds taken from air and soil is hrst used in the growth of the t
  plant. Later, as it approaches maturity, the energies of the plimf V 
    are devoted more and more largely to reproduction. In seed-bearing  
  plants, blossoms develop, followed by the fruits and seeds. X/Vithili  ·
  *Unless otherwise stated, seed—bearing plants are referred to in the discusSi0¤ A
(,5-: _·_. Eg Y following.
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_ Lessons on Farm Crops for 4-H Club .Members 7 ,    
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>ad- each seed is an embryo plant around which is stored concentrated T i i
bac, [Cod material—starches, sugars, proteins, fats, and mineral com- i   ;
for Pounds. This food supply supports the young plant which develops   Q
reed [mm the seed until it becomes established and is able to manufac- [  
the ture its own food supply. lt is the concentrated food material in l i    
y Seeds that makes them such a valuable source of animal {ood, l    
1nts 4 , Species and Vllfleiies of Plants. The term sj2ecies as used by    
yd, . botanists means a distinct or special kind of plant. F or example, red t ,    
the Clover, Kentucky bluegrass, corn, black locust, common ragweed, j '    
mm 3 the cocklebur and the potato; each is a species. The individuals in {      
rych  ` gt species are all very much alike in appearance. They interbreed or y    
Dm) _  ean be interbred, and their offspring differ from the parents only . ]  
,0),   in minor respects, as a rule. No two plants, even in the same species, Q {  
am  ` are exactly alike, however, and sometimes forms appear which are ' j  
my ? quite different from the common form, particularly in size, color of T l (  
I ,1, Q?  blossoms or other parts, and length of life. Under natural conditions j i _i,’ Z1
gm  I these variant forms interbreed with the common forms and are not   i iv, poyp  
ing-  ‘ perpetuated in many instances. \/Vhen one appears in a cultivated    
llyll   species, however, it may be noticed, and if it seems to have some ' '* i,»—  
Em.  -¢ superior qualities the seed is saved and the new form is perpetuated.    
and  i Such new forms are known as varieties or, to botanists, generally as I J    
 c subspecies. In many of our cultivated crops there are hundreds of    
md   varieties, and sometimes these varieties are quite different in appear- . .    
Owl  ·. ance. They interbreed, however, or can be interbred, and are obyi—    
l U)  — ously all one kind or species of plant.   good example of   species J  
[hc   in which there are numerous varieties is corn. Corn varieties differ I  
hm  = in color of the seed and other plant parts, in height, in length of p    
my  _ time required to mature, and in many other respects. \iVe also have . r    
ing ·,  many varieties of. wheat, oats, beans, soybeans, cowpeas, and in fact " .,..=  
ats,   of nearly all our important crops except the grasses. Recentlyrplant , yp  
md } breeders have produced a few varieties of several of our cultivated ;  
» grasses.   Qi
me  
my  L Botanical Classification of Plants. By grouping or classify-  
[hl, {  ing plants according to their likenesses and differences, we are able i  
am   to get a comprehensive picture of the plant world 215 3 Wl10l€ and I0  
im  , See the relationships among the thousands of different kinds or  
lh, V,  $p€CieS. The branch of botany which has to do with classihcation is  
 F l<¤OWn as systematic botany.  
Sm  [ A Species, as we have learned, consists of similar individuals ,  
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g~   8 Kentucky Extension Circular N0. 336
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    which interbreed and produce similar individuals, so that each
    individual is the link of a chain. Most species have one or, more
  .   often, a number of close relatives as indicated by the fact that all
    essential parts—for example, the flowers, leaves and ste1ns—are com-
  structed on the same plan. Such a group is known as a genus
    (plural genera). A genus, then, is a group of closely related species,
M   Red clover, white clover, crimson clover and alsike clover are species
  .    of the clover genus. Similarly, the different kinds or species of maple `
{   ar form the maple genus; the various species of oak the oak genus; and
l J3; the dozen or more different kinds of dock form the dock, or sorrell, (
{ .   genus.
  Genera that have certain plant characteristics in common form
( `fii a. family. The genera which comprise a family 1nay be quite unlike
l- Ill in many respects, but on close examination the similarity of various
 if  plants can be easily observed. The grasses, which comprise one of
( e.I_ the largest botanical families, vary in height from a few inches to
lh   fifty feet, or more as in case of the bamboo, the largest grass. Some `
f .fV:;i varieties of corn, also a grass, reach a height of fifteen to twenty ·
  feet. However, all the grasses have the same type of leaf, jointed
l lip` il stems, and flower parts similar in arrangement and structure. lu
Epi, g‘’r ;_j{1 the mustard family all genera have a certain kind of flower, and thc 5
  juice has a sharp or pungent taste. The members of the legume
  if [ family, so important in agriculture, all bear their seeds in a pod, and
(T}  f most of them have butterfly-shaped flowers.
  Groups of families which have certain characters in common i
  i are known as orders, and groups of orders form classes. Finally, the
  plant kingdom is divided into four great divisions. These are  
  the Thallophytes, in which are included the bacteria, fungi and °
  algae, all very simple plants, most of them microscopic in size; (2)
  the Bryophytes, which include the mosses and related species; (3)
  the Pteridophytes, the most prominent members of which are thc
  ferns; and (4) the Spermatophytes, which includes all plants which `
  bear seeds. The spermatophytes are the common conspicuous plants
  of held and forest, and nearly all cultivated crops are included in _
  this division. They are by far the most numerous and highly devel-
  oped of all groups. There are two classes of spermatophytes—lh€ _
  gymnosperms and the angiosperms. In the former the seeds are
  naked; while in the angiosperms they are covered—borne in a 5216- s
  The most important of the gymnosperms are the pines, cedafs and {
 
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T Lessons on Farm Crops for 4-H Club Members 9    
each other cone—bearing plants. There are only about 450 species of gym-    
1ore A nosperms. Practically all our common plants, including cultivated   .
; all G-Ops, are angiosperms. The number of species in the angiosperm T    
Con- gi-Oup is approximately 125,000. , , i ·  
illus Plant Names. All botanical names are either Latin or Latin- ‘    
UW » ized names from some other language. Words are Latinized by giv- T I ‘
me 4 ing them Latin terminations, or endings. For example, the name I.  
1PlC j Jefferson is Latinized into jeffersonia, and Clayton into Claytonia. , ‘    
and The name of a plant—the so—called scientihc name—is the name of ,    
ML its genus followed by the name of the species. The name of the ‘ l   §
genus corresponds to the family name of a person, and the name of , r “ 
arm _ the species to the given name. The names of genera are always y l _ j
like   capitalized; those of species are not, even when derived from a prop- ;    
l0uS er name. A few examples will make the system of naming clear. The j .  
3 Of ‘ clover genus is named Trifolium (three leaves). Trifolium pra-  
5 K0 tense is red clover; Trifolium incarnatum is crimson clover; Tri- i  It
MHC y folium repens is white clover. The oak genus is called Quercus. i  
rnty T \i\’hite oak is Quercus alba; red oak, Quercus rubra; and black oak, _ l  
tted Quercus nigra. Kentucky bluegrass is a member of a genus known   Ty
hl  ` as Poa, and the scientific name of this grass is Poa pratensis. Other , l if V  
the species of bluegrass are Poa compressa, or Canadian bluegrass; and  
une Poa annua, or annual bluegrass. li ` 3
and   The common names applied to plants differ not only in the vari ` i    
ous countries of the world, but in different parts of the same T y I  
non : country. Often the common name used for a certain plant in one ·  
the V section is used for some other plant in a different section. The scien- ,    
(ly tilic name of any plant is the same, however, in every country in , if 
md l the world. This is one of the important advantages of giving each T    
(Q) ; kind of plant a scientific name. {  
(3) ; Annual, Biennial and Perennial Plants. These terms are used T  
the i to indicate the natural life period of a plant. Animals live for only  
iCll   one year, or more often part of a year, dying completely after the  
HIS   seeds ripen. Winter annuals, of which wheat, barley and C1`i1nSOl1 Q, f;}
lll €lO\Ter are examples, germinate in the fall and ripen seeds the fol—  
rel-  y lowing spring or summer. Biennials are such plants as beets, onions,  
the Q Sweet clover, and the hollyhock, which produce seed the second year  
are   after planting. Perennials are plants that live for more than twO  
sae   }'€?11`S. Some perennials, like bluegrass, may live indehnitely; while  
nd , others, such as alfalfa, live only a few years. Red clover is a peren- _  
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    10 Kentucky Extension Circular N0. 336
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    nial that lives but two years in Kentucky, as a rule, but much longer
    in certain other areas.
  g   Reproduction in Seed Plants. Sexual reproduction occurs in
  E   all seed plants (spermatophytes). The reproductive organs are
  ·   borne by the flowers. In most plants a single flower bears both the
    male and female reproductive organs. In some, corn for example,
i ‘   Z} they are borne by separate flowers in different parts of the plant. ln
] _. i still other species (dioecious) they are borne on different plants, as _
    for example, in asparagus and hemp.
i _   VVhile the flowers of all plants are formed on a somewhat similar
  ji plan, they differ greatly in many respects. The most common plan
    among the angiosperms is as follows: The outermost set of parts is
    known as the calyx, and the separate members as sepals. Usually the
    calyx is green. The next inner set is known as the corolla, and the
g, Yi separate members as petals. The corolla is the showy part of the
    flower and is usually colored or white. Inside the corolla are the
i· '-,'- Tl stamens, and in the center the pistil. The stamens and pistil are V
ty   called the essential organs, since it is in these that the reproductive
  cells are formed. The part of the stamen producing the pollen
;_   I which carries the male reproductive cells is known as the anther,
ihqffi and the slender stalk which supports it as the filament. The pistil
    consists of a basal part, the ovary, containing the ovules in which
if T i are the female reproductive cells, and a style, the stalklike portion
  above. On some part of the style, usually the tip, is a moist, naked
ifi;   surface for the reception of pollen. This is known as the stigma. ln V
  some species the style is lacking. In corn, the silk is both style and
  stigma, as the entire exposed surface is receptive to pollen.
  Neither calyx nor corolla is present in the Howers of the grasses;
  instead, the stamens and pistils are enclosed by two chaffy parts ~
  . known as glumes.
  In corn, the anthers are produced on the tassels, and the pistils
  are borne on what is known as a cob. Some flowers have a calyx and ~
  no corolla.
  The development of a seed begins with the fusion, or union, of V
  male and female reproductive germ cells, microscopic in size, H
_   process known as fertilization. The beginning of fertilization is t
  pollination, or the falling of pollen on the receptive stigma of tht y
 y pistil. In each pollen grain are two germ cells, or nuclei. One of
   j these, known as the tube nucleus, extends into the style and finHll¥
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I Lessons on Farm Crops for 4-H Club Members ll f  
er into the embryo sac which contains the egg, forming a tube. The A 7 I
. other pollen cell divides, forming two nuclei which pass thru the   T
in pollen tube, thereby reaching and fusing with the female nuclei in _   1
rc the egg. After fusion, growth occurs by cell division and the embryo, , r F ‘
he . or young plant, takes form. After a certain stage of development y   °
[C, js reached, varying with different plants, the embryo ceases growth   1   $
in and becomes dormant. The dormant embryo, together with a store l    
as of food material which usually surrounds it, is enclosed in a hard, 1 . ·    
_ protective covering. This is the seed which, when planted in warm,   f    
al. moist soil, germinates, which means that the embryo resumes growth. i E E  
an ln some instances the seed or seeds produced by a single flower I i ¤
is is contained in a pod or in a more or less fleshy fruit, as, for example, l    
he the seeds of berries, apples, peaches, melons, tomatoes, and peppers.     j  
he Self Pollination and Cross Pollination in Plants. In many   I l  
he species of plants the stigma of the flower is almost always pollinated   I gil
he 1 by pollen from the same flower or from other flowers on the same   1  
1re  I plant. This is known as self pollination, and it results, of course, i   f
V6 I in self fertilization. In other species, cross pollination usually I _    
e11 occurs, which means that the pollen which reaches the stigma of   g
er,  _ one plant is produced by another plant or other plants. In still : — {  
1til ‘ other plants, both cross and self pollination occur. A   if  
ch The important crop plants naturally self pollinated are wheat, y   ,
On . oats, barley, rice, soybeans, cowpeas, and potatoes. In some in- p    
Cd stances self pollination occurs because the anthers discharge their 1 y { tj
In pollen before the flower opens. In other species—wheat and oats, · *_, 
nd V for example—the pollen is discharged as the flower opens, and some ¥ f l L ;
of it falls inside the flower and on the receptive stigma. The flower _ 1    
CS? 1 remains open but a few minutes, so that there is little chance of i  ii?
Us ‘ pollen from other flowers getting in. However, a very small amount I  
of crossing does occur even in naturally self fertilized plants. In l f l., 
rift Crossing two varieties of self fertilized plants, it is necessary to remove  
nd ` the anthers before they open and then to cover the flower by a small V  
y bag to keep out undesired pollen. As soon as the stigma becomes jp  
Of receptive it is hand pollinated with pollen from the selected plant.  
V Ia The most important naturally cross pollinated cultivated Crop  
ls A is C0rr1. The pollen is borne on the tassel, and it is so light that it is  
[hc  . Carried away from the plant bearing it and pollinates the silks on ff  
Of Other plants. An isolated corn plant usually produces only a few  
1lll' I kernels because of lack of pollination. I  
. i a
 f1  

 E   {
    12 Kentucky Extension Circular No. 336
    lt is an easy matter to self-pollinate corn. The ear is covered
    witl1 a small paper bag before tl1e silks appear. At the same time)
    or a little later, the tassel is enclosed in a 10- or 12-pound paper bag_
    The pollen accumulates in tl1e larger bag, and when the silks are
  t   well out tl1e pollen which has accumulated is poured over the silk_
    The silk is protected from other pollen by again covering the ear
  _,   shoot with the larger bag. This is usually left on until the corn is
  ‘_pp   gathered. ‘
l   ‘`‘. Other crops wl1icl1 are naturally cross pollinated are rye, clover-, ·
l ·   and many of tl1e pasture and meadow grasses. Self pollination of  ~
    naturally cross pollinated crops usually results in reduction in size
  of plants a11d a loss of vigor. Cross pollination of naturally sell
ly   pollinated crops may result in increased vigor.
l pj Crops in which both cross and self fertilization occur include T
  tobacco, cotton, and tl1e sorghums. Complete self fertilization may `
l _,Ag   be effected by covering the flowers with a bag. This is often done
l·· Tit with tobacco to prevent any crossing with other varieties or inferior
  plants. No reduction in vigor results.
    _i,‘— How Plant Characters are Transmitted. Plant characters are
    , those qualities which identify a plant and serve to distinguish it
{jj agi from other forms. All the characters of a plant are represented in
·‘_A _ if the cells of which tl1e plant body is composed by what are called
  genes, "factors", or determiners. ln some way not clearly under:
  ° stood these factors have the power to regulate tl1e growth of the
  pla11t and produce its distinguishing features. We 11ave learned
  that plants produce germ cells especially for reproduction. Tl1e
  reproductive cells, called gametes, carry the same factors as the cells i
  of tl1e plant which produced them. If both male and female gametes
  are produced by the same pla11t as is true in self-fertilized plants, y
  1 each carries the same hereditary factors and tl1e fertilized egg which
  is the product of their fusion develops into a plant like tl1e parent.
  For example, suppose we have a variety of wheat, a self-fertilized `
  crop, witl1 long beards and red seeds. Both male and female gamet€S
  carry factors for long beards and red seeds and the plants resulting _
  from their fusion will also have long beards and red seeds as long
    as self-fertilization continues. The progeny of a self-fertilized plalli
  is known as a pure line. Suppose, however, the bearded variety with V
  red seeds is crossed with a variety which 11as very short beards and
  white seeds. One gamete will carry factors for long beards and téd _
l  
.,a. l  ;

 l
 
J i i
Lessons on Farm Crops for 4-H Club Members 13 f i  
3d Seeds and the other factors for short beards and white seeds. As a j l   f
le) result the cells of the resulting hybrid plants known as first-genera- y Q! Y
,g_ tion, or F1 hybrids, will carry factors for all four characters, namely _ [ Q
rc long beards, red seeds, short beards and white seeds. In this particu— 4 y   2
'k_ lar cross, the F1 plants will have short beards and red