PLT 132 Plant Propagation Seeds – part 3: Seed Technology
Transcript of PLT 132 Plant Propagation Seeds – part 3: Seed Technology
PLT 132 Plant Propagation
Seeds – part 3: Seed Technology D. W. Still
Seeds – Part 3 Chapters 6 & 7
1. Harvesting and Processing Seeds
a.) Standard germination test (% normal seedlings) b.) Excised embryo test (woody plants, dormant seeds) c.) tetrazolium test (measures respiration – i.e., viability) d.) vigor test - “seed vigor comprises those seed properties which determine the potential for rapid, uniform emergence and development of normal seedlings under a wide variety of field conditions”. - includes accelerated aging, controlled deterioration, cold test, cool test, electrolyte leakage, seedling growth rate, high temperature tests, light tests, etc.
2. All (commercial) seeds will be tested
a.) All seeds must be collected, dried, cleaned, and stored. b.) Fleshy fruits (watermelon) or dry (lettuce, maize, etc.)
Seeds – Part 3
4. Seeds must be stored: a.) Orthodox vs. recalcitrant b.) Moisture content and temperature are key components. - vigor > normal germination > viability c.) Seeds are genetic resources.
3. Seed treatments serve several purposes: a.) Seed protectants: chemical trts, heat trts, innoculation. b.) Aid in planting: pellets, film coating. (Figs. 6-18, -19) c.) Aid in germination under stress: Priming
National Center for Genetic Resources Conservation – Ft. Collins CO
ca. 1958
Cryopreservation in liquid N2
“Noah’s Ark” Svalbard Global Seed Vault, Norway 26 February 2008
http://news.nationalgeographic.com/news/2008/02/photogalleries/seedvault-pictures/index.html
Seeds – Part 3
1. Seed transition from seed development to germination
a.) Germination with respect to water uptake (see figure 7.3)
Phase
II III I
Wat
er u
ptak
e
Time
Lag
Seeds – Part 3
1. All seed germination is based on water relations
i.) Matric potential = ψm
ii.) Osmotic potential = ψπ
iv.) ψcell = ψm + ψπ + ψp
a.) Water potential = ψcell
iii.) Pressure potential = ψp
Seeds – Part 3
b.) Priming i) alleviate thermo- and photo-dormancy
1. Environment affects seed germination
c.) Water potential i) Embryo must generate force
a.) Temperature i) Max, min, optimum
b.) Light i) red light promotes, far-red or dark inhibits
Seed Technology
• Pelleted or coated seeds – Coating (diatomaceous earth) – Binding (inert materials)
• Change size and shape of seeds – Uniform size
• Precision planting (tractors)
Seeds – Part 3
b.) Primary: dormancy that is initiated during seed development
1. Dormancy
a.) definition: the inability of a seed to germinate when environmental conditions are favorable for germination to occur.
i. Exogenous – external to embryo ii. Endogenous – embryo specific
Seeds – Part 3
1. Dormancy
b.) Primary: dormancy that is initiated during seed development
i. Exogenous 1) Physical – e.g., seed coat, fruit parts Scarification may be needed
2) Chemical – chemicals produced by seed or fruit Leaching may be needed
ii. Endogenous
A) non-deep, intermediate, deep 2) Physiological – including: 1) Morphological – embryo is not fully developed
B) e.g., photodormancy, after-ripening, stratification
Seeds – Part 3
1. Dormancy
b. Secondary dormancy – seeds may lose primary dormancy and subsequently re-enter dormancy again. This is secondary dormancy.
i. Thermodormancy – seeds exposed to high temperatures fail to germinate when returned to a permissible temperature.
2. Release from dormancy
a. Hormonal balance is key to germination
b. GA promotes germination, ABA prevents germination
Seeds – Part 3
http://www.psy.ritsumei.ac.jp/~akitaoka/sun.jpg
Red light (660 nm)
Pr
Pfr
Seeds – Part 3
Filtered light (far-red) 730 nm
Pfr
Pr
18
X
F1
Recombinant inbred line (RIL) ‘Diplomat’ (Iceberg) X ‘Margarita’ (Butter)
Improvement of germination in lettuce through genetics and breeding
19
Recombinant Inbred Line (RIL) F1
F3
….. ….. ….. …..
F4
….. ….. ….. …..
F5
….. ….. ….. …..
F6
….. ….. ….. …..
F7
….. ….. ….. ….. Single seed descent
RIL population with 131 families (Dip x Mar)
F2 ….. ….. ….. …..
F8
0
10
20
30
40
50
60
70
80
90
100
178.2 24
311
6.2 139
218
177 88 10
118
9 83 173
124 92 16
324
022
1 410
.3 55 81 244 65 18
822
220
2 41 43 3D 89 130
138
217.2 11
119
4 28 93 12 193 3L 23
314
.1 54
Family Number
Fina
l ger
min
atio
n (%
)
Distribution of germination response after exposure to FR-D among RIL (D X M)
Dormant
Non-dormant
Far-red light can induce dormancy of lettuce seeds. Ability to germinate in FR24-D environment is a complex (quantitative trait).
E33M59D870.0E35M55D3463.7
E33M48D19915.7E45M59D23522.2E45M49M26524.2
E33M48M34832.2E33M54M49435.9
E33M61D43247.5
E33M59D24568.0
E33M62D8379.4
E45M61D122104.0E36M62D522109.5
E33M49D363E33M49D108122.8
E45M49M131140.7
E36M62M61155.2
HTD
_T50_f1.1
FRD_FG
_f1.1LTR_T50_g1.1
HTR_T75_g1.1
1
E35M59D198E35M59M1990.0
E49M60D230E45M48D15813.2
E35M59D31418.3E35M55D7523.4E35M55M22826.2E45M59D27929.0E33M59M25934.5E35M55M26639.8E35M59D17744.1
E45M59M38154.3
E33M49D9266.9
E45M61M32884.4E33M59D19486.8
E36M62M63109.4E33M54M239110.2E45M48D587111.0E45M48D603115.6
E35M55D506130.2E33M48D434131.4E33M49M456132.2E33M54M539135.5E45M61M453140.6
E33M54M549155.2
FRD_T25_f2.1
HTD
_T75_g2.1
HTD
_T75-25_g2.1
2
E33M49M3840.0
E45M61M37929.5E49M49D10440.9E33M61M31851.1E33M54D16368.5E33M59D256E33M59M25872.7
E45M48M6475.1E33M48D27876.7E45M61M86E36M62M37678.7
E45M48D9085.2E49M60M34692.7E33M49M28895.1E33M59D282E33M54D26596.7
E35M59M48397.5E49M60M21997.9E49M49M140102.0E49M60D409E49M60M405104.4
E49M60M468E35M59M180104.8
E33M61D101106.4E45M59D262113.9E33M62M249116.7E49M60M249127.5E45M61D326129.9E33M61M329141.3E45M49D425144.1E36M62D221145.7E35M59M326146.1E33M62M260149.4E45M49D202151.8E33M62M73154.2
HTR_T75_f3.1
HTR_T75_f3.2
HTR_T75-25_f3.1
HTD
_T75_f3.1H
TR_T50_g3.1
HTD
_T25_g3.1
3
E59M60D1540.0
E45M59D47026.0
E45M48M8846.8E49M60D10648.0E45M61M19853.1E33M61D25554.7E36M62D39457.5E33M61D6760.3E33M61M35563.6E45M48M7767.7E33M48M444E45M59M28770.1
E45M61D33178.7E35M59M14183.3E35M59M32584.5
E33M59M103107.1
E45M59M397123.9
E45M59D238130.9
LTR_T25_f4.1
LTR_T50_f4.1H
TD_T75_f4.1
HTD
_T75-25_f4.1LTR_T25_g4.1
4
E33M49M177E45M48M2180.0
E49M49D18613.9
E35M55D8921.9E49M60D8026.5
E33M54M38139.2
E35M59M29751.9E45M48D30354.3E45M59M45155.5E33M54M35257.1
E33M59M20673.9
E33M54D28291.4
E59M60M115115.3
HTR_T75-25_g5.1
HTD
_T50_g5.1
5
E45M49D4120.0
E49M49D18218.3
E49M60D39128.0E36M62M44233.5E45M59M32434.3E36M62D118E36M62M11735.6
E33M62M24646.9E35M59D15252.0E35M55M25153.6E33M48M28456.9
E33M49D521E33M49M51572.2
E33M59M21574.2E45M59D26577.9E33M54D42581.6E33M59D46684.4
HTD
_T75-25_f6.1
FRD_FG
_f6.1
FRD_T50_f6.1
FRD_FG
_g6.1
6
E45M61D1530.0
E35M59D43813.9
br20.9
E33M61M26627.9
E33M54M39438.3
HTR_FG
_f9.1
HTR_T50_f9.1
HTR_T75_f9.1
HTR_T75-25_f9.1
FRD_FG
_f9.1
FRD_FG
_f9.2
FRD_T25_f9.1
HTR_FG
_g9.1
FRD_FG
_g9.1
FRD_FG
_g9.2
FRD_T25_g9.1
FRD_T75_g9.1
FRD_T75-25_g9.1
9
E45M59D3180.0
E35M59M33713.9
E33M61M38728.5
10
E49M60M465 0.0
E33M54D552 26.7
E35M59M81 41.3
E45M61D319 51.5 E45M61M132 55.6 E33M48M358 E33M62D320 60.7
E33M48M167 79.0
HTD
_FG_g7.1
7
E33M61D247 0.0 E36M62M116 5.5 E45M49M127 E45M61M385 E33M61M70
10.6
E33M48D247 E49M60D321 E45M49D387 E33M62D220
11.0
E45M48D345 12.2 E49M49D144 15.0 E33M59D184 25.2 E35M59D377 42.7 E45M48D67 46.8 E35M55D184 49.6
E59M60D181 70.3
LTR_T50_g8.1
8
(Hayashi et al. 2008)
Determining the location of the genes that confer ability to germinate
Genetic mapping
Chromosome DNA markers
QTL
Introgression of alleles from wild species improves high temperature germination in lettuce