Classes and importance of leguminous crops

1. Classification of Legumes

2. Legumes (Pulses)
• Latin word “legere” = to gather
• family Leguminosae ( Fabaceae)
• consist of :
- 750 genera
- 19,000 species of herbs, shrubs,
trees, and climbers

3. • Four (4) subfamilies:
▫ Papilionoideae
▫ Caesalpinoideae
▫ Mimosaideae
▫ Zwartzioideae (small subfamily of about
80 species and relatively unimportant
economically)

4. 3 Subfamilies:
Mimosaceae
Caesalpiniaceae
Papilionoidae

5. Characteristics
a) pod-bearing plants;

6. b) Dicots –leaf veins are netted;

7. • leaves divided into leaflets
trifoliate pinnate

8. Leaf shapes & arrangements

9. 1. oblong;
2. cuneate;
3. cordate;
4. linear;
5. lanceolate;
6. ovate;
7. oval
Fig . Different leaf shapes of legumes

10. 8. bi-pinnate;
9. pinnate;
10. palmate;
11. simple;
12. trifoliate;
Fig . Different leaf shapes of legumes

11. 13.branch of Pisum
showing (a) five-
branched tendril and
(b) stipule;
14.(c) bi-pinnate leaf
showing position of
pulvinus;
15.Acacia seedling
showing (d) simple
phyllodes, and (e) true
compound leaves
Fig. . Some leaf arrangements of legumes

12. c) have nodules on roots;
soybean

13. • But not all produce nodules
Ex. Subfamilies of: Caesalpinia, Cassia,
and Bauhinia
• Highest incidence of nodulation appears in
Papilionoideae followed by Mimosoideae

14. Bauhinia sp

15. c) Distinctive flowers
and pods
-Flowers are bilaterally
symmetrical
-Seeds rich in oil (up
to 50%) and protein
(e.g. 15-50%)

16. • Best identified by their reproductive structures
1.front view of flower of Pisum sativum
(pea);
2. petals of P. sativum;
3. flower of Psophocarpus tetragonolobus
(winged bean);
4. flower of P. tetragonolobus in
longitudinal section. a-posterior or
standard petal; b-lateral petal; c-keel
petals (carina); d-sepals; e-stigma;
f-style; g-anther; h-filament; i-ovary wall;
jovule
Figure 2-1. Subfamily Papilionoideae

17. Legume – Papilionoid flower

18. Legume – Papilionoid flower
Banner petal

19. Legume – Papilionoid flower
Banner petal
wing

20. Legume – Papilionoid flower
Banner petal
keel
wing

21. Legume – Papilionoid flower
Banner petal
keel
wing
Stamens: 9 + 1

22. Legume – Papilionoid flower
Banner petal
keel
wing
Stamens: 9 + 1

23. Figure_.Subfamily Caesalpinoideae.
1. bud of Cassia sp.;
2. flower of Cassia sp.;
3. longitudinal section of Delonix regia
(Flame of the Forest or Poinciana)
a-petal;
c-stigma;
e-filament;
b-sepal;
d-style;
f-anther;
g-anther of staminoid;
h-posterior or standard petal;
i-ovary wall;
j ovule.

24. Delonix regia
Cassia acutifolia
Cassia alata (Akapulko/asunting)

25. Figure _. Subfamily Mimosoideae
1. Floret of Adenanthera pavonina;
2. inflorescence (globose head) of
Leucaena leucocephala in longitudinal
section showing arrangement of florets
on torus;
3. floret of L. leucocephala (side view);
4. (top view). a-petal;
b-sepal; c-stigma; d-anther;
e-filament; f-style; g-ovary

26. 1. Strongylodon lucidus;
2. Tamarindus indica;
3. Acacia farnesiana;
4.Parkinsonia aculeata;
5. Prosopis pallida;
6. Lablab purpureus;
7. Pisum sativum;
8. Psophocarpus tetragonolobus;
9. Arachis hypogaea;
10. Cicer arietinum;
11.Leucaena leucocephala
Figure _ . Legume pods

28. Legume examples
Foods
▫ Peanuts
▫ Mungbean
▫ Soybeans
▫ Cowpeas
▫ Winged bean
▫ Peas
▫ kidney beans
▫ green beans
▫ fava beans
▫ lima beans
▫ chick-peas (Garbanzo
beans)
▫ black-eyed peas
▫ lentils
Forage
▫ alfalfa
▫ red clover
▫ white clover
▫ sweet clovers
▫ vetches
Trees
•Ipil-ipil
• madre de cacao
•Acasia
•narra

29. Peanuts

30. Adjuki bean, Phaseolus mungo

31. soybean

32. Beans, Beans, Beans
varied in seed
size and color
Kidney bean Black bean Pinto bean

33. Kidney beans

34. lentils

35. Cowpea ( Vigna unguiculata L.)

36. peas

37. Fava Beans

38. Lima beans

39. Grain Legumes
Vigna umbellata – Rice bean - Tahuri

40. Mungbean – Vigna radiata . Wilzeck

41. Tamarindus
indica,
tamarind

42. Important uses:
• Human food
• Animal feed
• Fuel wood
• Soil improving components of agricultural
& agroforestry systems
▫ Intercrop
▫ Rotation crop
▫ Relay crop

43. ▫ Trap crop
▫ Green manure crop
▫ Cover crop
▫ Hedgerow crop
▫ Sustain soil fertility because of its N-
fixing ability

44. Soybean products

45. Nutritional value
• Legumes rich in protein (20-30%) N
• contain some fats but usually less
starches than cereal grains
• Has more amino acid composition
which differ from cereal grains

46. Nutritional value
• High fiber levels
• Isoflavones –lower cholesterol levels
• Seeds of almost all legumes are toxic if
eaten uncooked due to proteins or
peptides that inhibit digestive enzymes
(Alkaloids, cyanogens)

47. A Poisonous Legume
Abrus precatorius – Precatory Bean
Abrin – toxin, one of most
toxic substances known
1 crushed seed can be
fatal if ingested

48. feeds

49. Forage Legumes
Alfalfa – Medicago sativa
- king of forage crops
being associated with
horse husbandry
Clovers – Trifolium
Sweet Clovers - Melilotus

50. Ipil-ipil
For agroforesty, fertilizer,
fuel, landscape, & timber
narra

51. For cropping systems
Fig. _. Corn-legume intercropping
Crop rotation

52. Important points
• Legumes fix nitrogen
• Legumes rich in protein
• Legumes easily stored and harvested

53. Nitrogen fixation
• Roots form associations with bacteria that
fix atmospheric nitrogen
• Rhizobium species live in root nodules
• provide “free” fertilizer (N)
• Atmospheric N can’t be used unless
absorbed in the form of:
- nitrate (NO3-) or
- ammonium (NH4+)

54. • Assignment:
1. Read Nitrogen Cycle and Nitrogen
Fixation in Legumes

55. Mungo -24 % protein & rich in
vitamins (e.g. thiamine, ascorbic acid
& mineral salts esp. calcium and
sodium)
• feeds, ornamentals, timber, fuel,
medicine, green manure
• components of farming/cropping
systems
• restores soil fertility

56. • Constraints to Food Legume Production:
1. Social & economic factors
- poverty, tradition, fashion, social status,
ignorance or lack of experience;
- lack of demand/poor prices;
- only a subsidiary crop (less priority)

57. 2. Physical and biological factors
-adaptation ( grown in marginal areas)
-agronomic/management (lack of available
improved cultivars)
-poor land preparation (competition of weeds)

58. - growing crop at inappropriate season of the
year (especially if fitted into cereal-based
cropping system
- pest and diseases
- biological N-fixation
- flower shedding and embryo abscission

59. Characteristics:
1. pod - dehiscent (splits into two)
- indehiscent (called loments)
- others have single seed
ex. Winged seed of narra, dispersed by
wind

60. 2. Ability to fix N or convert atmospheric
N into usable form
- through symbiotic relationship
(bet. legume and bacteria)
- host specific

61. Cross
Inoculation
Group
Rhizobium species Legumes
included
Host genera
Alfalfa group R. melitoti Alfalfa/ sweet
clover
Medicago/Melilotus
Clover group R. trifolii clovers Trifolium
Pea group R. leguminosarum pea Pisum
vetch Vicia
Sweet pea Lathyrus
Bean group R. phaseoli Beans Phaseolus
Lupine group R. lupini Lupines Lupinus
Soybean
group
R. japonicum Soybean Glycine
Table . Host specificity of Rhizobium-legume associations

62. Cross
Inoculation
Group
Rhizobium
species
Legumes
included
Host genera
Cowpea
group
R. sp cowpea Vigna
Lespedeza Lespedeza
Crotolaria Crotolaria
Kudzu Pueraria
Peanut Arachis
Lima beans Phaseolus

63. • Symbiotic relationship between
macrosymbiont (usually a legume) and a
microsymbiont (Rhizobium)
• Nodules –site of N fixation
But some legumes fail to nodulate due to:
1. unsuitable condition
2. absense of endophyte (microsymbiont)

64. Table _. Legume species and the amount of
atmospheric N fixed/assimilated per hectare
Legume Species Amont of N fixed
(kg/ha/year)
alfalfa 50-350
peas 30-140
peanuts 88
soybean 100
Forage legume 10-550

65. Biological N fixation:
- microbes fixes 150-250 lbs of N/acre/yr
-Bacteria trap atm. N and transformed to
NH3;
- NH3 combines with organic compounds to
form amino acids and proteins;
- In turn plant supplies CHO and energy for
their metabolism

66. • Biological N fixation pathway:
N = N (atmospheric N)
nitrogenase enzyme
+ 2H
NH = NH (diamide)
+ 2H
NH2 = NH2 (hydrazine)
+ 2H
2NH3 (ammonia)
+ alpha-ketoglutaric acid
amino acids
+ other amino acids
proteins