DR. Paul Njiruh Nthakanio………TUK
Dr. James I. Kanya …………………UoN
Dr. John M. Kimani ………………...KARI Mwea
Dr. Raphael Wanjogu ………………MIAD


FUNDED / COLLABORATORS
NATIONAL IRRIGATION BOARB , TUK, UoN, KARI
HYBRID RICE PROJECT

Work started in 2011 under NCST funding.

In 2012, we approached NIB which agreed to support the project
financially.

Project is being conducted in four phases
Phase one: Adaptability of breeding rice lines in Kenya at KARI
Mwea (In green house and natural conditions):-Done
Phase Two: Breeding. Hybridization between Basmatis (370 and 217
) as paternal parents and PGMS and TGMS rice lines
(Obtained from IRRI):- On going.
Phase Three: Natural sterility induction in Mombasa; On going.
Phase 4: Production of hybrid rice in Bunyala and Mwea.
Publication
Kanya J.I., Njiru P.N., Kimani J.N., Wanjogu R.K. (2013):
Evaluation of Photoperiod and Thermosensitive Genic
Male Sterile Lines For Hybrid Rice Seeds Production in
Kenya. International Journal of Agronomy and Agricultural
Research (2223-7054 (Print) 2225-3610 (Online)
http://www.innspub.net Vol. 3, No. 2, p. 21-39, 2013).
1.1 Background : Rice production in Kenya

Over 300 tonnes of rice is consumed in Kenya.

About 100 tones is locally produced.

In Kenya rice is mainly grown in Mwea, Ahero, Bunyala, West
Kano, Yala Swamp (MoA, 2011).

About 98% of Mwea rice is Basmati.

By year 2030 Kenya population is expected to be 60.0million.

Rice yield is expected to increase 600% to feed the population.
Table1. Source: NCPB and Department of Land, Crops
Development and Management, USDA
Year
Kenya Population
2006
38m
2013
40m
2030
60m
2050
??
Production (Tones) 64,840 100,00 ??
??
Area (ha)
??
23,106 ??
??
Global Concerns

High yielding varieties (HYV) dwarf rice varieties
have reached breeding plateau hence global
yield.

Green revolution technology now need reinnovation.

Low yield per hectare of Basmati rice (4.1ha)
(Ministry of Agriculture, 2010).

Rice consumption is far above production.

Rice diseases like blast continue to reduce
yields (Wanjogu and Mugambi, 2001).

Hybridization has been used to increase rice
yield per hectare (Zhang, 2010).

High yield is due to heterosis or hybrid vigour.
1.5 Measuring heterosis?
Mid-Parent (MP) heterosis
F1-MP X100
(F1 performs better than mean of two parents): MP
Better Parent (BP) heterosis
(F1 performs better than better parent):
F1-BP X100
BP
Standard heterosis
(F1 performs better than the check variety):
F1-CK X100
CK

To make a cross Male and female parents are
needed.

a) Female need to have non-viable male
gametes so that they can be crossed with
another variety.

b) Male parent: need to have viable pollen.
x
Female with
sterile pollen but
fertile ovule.
Male parent with
fertile pollen
Hybrid plant
emasculation is done to induce male sterility, a
condition in which the pollen grains are not viable to
fertilize normally to set seeds.
 Male
Methods of male emasculation
a) Environmental Genic Male sterility method (EGMS)
‣ PGMS – photoperiod sensitive genic male sterile lines.
Uses long daylight length to induce sterility
‣
TGMS - thermosentive genic male sterile lines Uses high
temperature to induce sterility
b) Cytoplasmic genetic male sterility (CMS)
Male sterility is controlled by the interaction of a
genetic factor (S) present in the cytoplasm and
nuclear gene (s).
c) Chemically induced male sterility
Male sterility is induced by some chemicals
(gametocides).
.
Temperature
high


Based on the
discovery of
P(T)GMS mutant
Reproductive Upper Limit
Sterile
F1 Seed
Production
Male sterility
controlled by 1 or 2
pairs of recessive
gene(s)
Partial Sterility
Fertile
S-line
Multiplication
low
Critical Sterility
Point
Critical Fertility Point
Reproductive Lower Limit
Model of Sterility / Fertility Expression for TGMS Rice
Use hybrid rice technology to raise yield
i)
Introduce EGMS in Kenya and test for
their adaptability.
ii) Develop Basmati with EGMS gene.
iii) Produce hybrids by crossing EGMS-Basmati
with conventional Basmati.
EGMS included; PGMS and TGMS LINES FROM
IRRI.
These are:PGMS Lines
 V1 - IR-73827-23-76-15-7S
 V3 - IR-75589-31-27-8-33S
TGMS Rice
 V2 - IR-77271-42-5-4-36S.


Basmati370
Test for EGMS adaptability
 Sowing of EGMS in KARI Mwea.

Growth at sterility conditions and spikelet
fertility assessed.

Growth under fertility inducing conditions
and spikelet fertility assessed.
a
b
Fig. a and b show EGMS and the greenhouse
respectively
a
b
c
a). EGMS under sterility inducing conditions, b).
sterile panicle and c). Pollen from sterile panicle.
a
b
C
a). EGMS rice plant, b). Panicles and c). Pollen from plants
grown under fertility inducing conditions respectively with
grains.
Evaluation of spikelet and seed fertility
Rice line
1
2
3
1
2
3
1
2
3
V1PGMS
V2TGMS
V3PGMS
Average
V1PGMS
V2TGMS
V3 PGMS
Average
V1PGMS
V2TGMS
V3PGMS
Average
Treatmen Fertile Pollen (blue
t
black staining pollen)
%
LDL + HT
0
LDL + HT
1
LDL + HT
0
0.33
NDL + HT
0
NDL + HT
0
NDL + HT
0
0
NDL + NT
64
NDL + NT
60
NDL + NT
55
59.67
Average
Seed set per panicle
%
0
3
0
1
0
2
0
0.67
45
30
26
33.67
Hybrid seeds and Anthocianin
a
b
c
a). Hybrid rice, b and c show hybrid rice with deep anthocyanin at the
base of the plant.
V1 xb370 cross
Lane 1: Rader, V1xB217, V1 xB370, V2xB217,
V2xB370, V3xB217, VxB370)
Ladder V1,V1xB217, B217
Doubled haploid
Calli from anthers of hybrid plants
Sabaki river
S/No
1
2
3
4
5
5
6
New line being tested
Remarks
V1B217P001
V13B217P002
V1B217P003
V1B217P004
V1B217P005
V1B217P006
V1B217P007
Long awns
Long awns
awnless
Short awns
Long awns
Short awns
Short awns
Line Identity
Number of lines under trial
V1XB217
52
V2X217
V3X217
V1X370
V2X 370
V3X 370
23
35
38
55
55
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

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NATIONAL COUNCIL FOR SCIENCE AND
TECHNOLOGY
M2U00022.MPG
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