sess10 1 z.m. kinyua adaptation and improvement of the seed-plot technique in smallholder potato...
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Adaptation and improvement of the seed-plot technique in smallholder
potato production
Presentation by
Z.M. KinyuaPlant Pathologist & National Coordinator
Crop Health Programme Kenya Agricultural Research Institute
[email protected]+254 (0)733 999444
Presentation during the 9th Triennial African Potato Association ConferenceThe Great Rift Valley Lodge, Naivasha, Kenya
30 June-4 July 2013
Common sources of seed potato
Farmers commonly obtain seed potato for planting from:• own previous crop harvests• ‘neighbours’ • market places • Distant potato-producing areas (high altitude zones)
Other sources (Kenya)• KARI (e.g. Tigoni station & its sub-centres)• Agricultural Development Corporation -Molo• Individual private companies (e.g. Kisima Farm, Midlands Ltd)• Farmer groups/CBOs producing clean seed potato• Individual farmers with reputable seed potato
> 95%
< 5%
Different inputs, different expectations
Poor quality seed
Good quality seed
Bacterial wilt - a consequence of planting infected seed tubers
A devastated potato field
A healthy, promising potato crop
The principle
Improving seed potato quality through a seed-plot technique
Site selection for seed-plot establishment
Might be contaminated, especially if low-lying!
Probable sites (bush land, other crops, homestead, etc.)
Schematic presentation of seed-plot practice
Seed plot
Seed plot
Seed plot
Seed plot Main field
Main field
Main fieldMarket or
home consumption
Market or home
consumption
Market or home
consumption
Season 1
Season 2
Season 3
Season 4
(Initial multiplication)
1. Adaptation of potato seedplot technique10 seed-plot trial sites in Kenya, managed by farmer groups:• Kianthumbi - 3 seed plots • Mutethia Mbuyene - 3 seed plots • Kibaranyaki - 3 seed plots • Muchicha - 3 seed plots
Done during the 2010 long rains season (April-July) Repeated during the 2010 short rains (October-December)
5 seed plots hosted by farmer groups for three seasons (2010-2011)in Uganda:• Rushebeya • Kayanga • Kyambura • Burema • Mpangango
Productivity assessed by determining tuber yields (number & weight per unit area)
Methodology
Active participation of a farmer group in establishment of a potato seed plot
Establishing a potato seed plot
• A well-dug bed (loosened soil)
• Narrow bed marked (1.8m width) to avoid stepping in when working.
• Fertilizer applied (DAP - 18: 46: 0) and raked in.
• Furrows made and tubers placed at a spacing of 30cm by 30cm.
Methodology (cont’d)
Established potato seed plots
2. Effect of fertilizer application in potato seed plots
General informationCultivar used: Asante Trial location: Abo West Division, Meru Central District, Kenya. Seedplot size: 2.4m by 1.8mSpacing: 30x30cm
thus accommodating 8 rows of 6 tubers (48 plants) per plot.
Two fertilizer types:diammonium phosphate, DAP (18: 46: 0) Mavuno Planting (10: 26: 10)
Three fertilizer rates:no fertilizer application (0kg N/ha), DAP low level (45kg N/ha)DAP high level (90kg N/ha)
Methodology (cont’d)
CountryTrial site (Group name or host farmer)
%Small tubers
%Medium tubers
%Large tubers
Tubers/m2
Multiplication ratio
Yield (t/ha)
Kenya Muchicha (Munyugi P) 5.99 54.43 39.58 49.4 4.5 41.7Kenya Muchicha (Bundi H) 7.16 61.30 31.54 48.5 4.4 32.1Kenya Kianthumbi (Kimathi S) 10.33 70.41 12.37 54.4 4.9 28.4Kenya Kianthumbi (Kaimenyi E) 5.27 71.14 23.60 62.7 5.6 40.7Kenya Kianthumbi (Kinoti R) 5.51 60.64 33.84 44.5 4.0 45.1Kenya Mutethia Mbuyene (Wambui) 6.84 56.16 36.94 65.9 5.9 69.8Kenya M Mbuyene (Mbijiwe T) 7.45 54.02 33.69 41.5 3.7 44.6Kenya M Mbuyene (Kinya M) 5.85 67.02 26.61 60.4 5.4 40.7Kenya Kibaranyaki (Murithi I) 8.96 66.92 24.12 28.6 2.6 21.6Kenya Kibaranyaki (Agwima S) 8.52 67.41 27.58 39.7 3.6 30.9Uganda Kyambura 20.16 75.22 4.63 54.7 4.9 45.1Uganda Kayanga 26.45 66.19 7.36 69.6 6.3 74.1Uganda Rushebeya 20.35 73.74 5.91 40.0 3.6 21.6Uganda Burema 29.49 61.22 9.29 63.6 5.7 66.4Uganda Mpangango 49.35 45.86 4.79 47.2 4.3 15.1
ResultsSeed-plot potato yields in various sites in Kenya and Uganda
• Productivity of seed plots: 28.6 to 69.6 tubers/m2
• Mean multiplication ratio: up to 6 tubers per plant.
• Yield in most of the sites was above 40 tonnes/ha.
indicating that the technique was easily adaptable in many areas
• Sites that had low yields also had poor tuber multiplication ratios.
Results (cont’d)
Fertilizer regime
Number of tubers by size
Total tubers
Total tuber yield (kg)
Average weight
per tuber (g)
Tuber multiplication rate
Small Medium Large Zero 32.25a 102.50a 12.50a 147.25a 3.80a 25.82a 4.09a
DAP-Low 23.25a 163.25b 33.75ab 220.25b 10.16b 46.12b 6.12b
DAP-High 31.50a 162.00b 43.00b 236.50b 12.04b 50.93b 6.57b
Mavuno-Low
29.75a 155.75b 30.75ab 216.25b 10.35b 47.85b 6.01b
Mavuno-High
26.75a 133.50ab 49.25b 209.50b 11.14b 53.19b 5.82b
Note: The parameters are taken from plots measuring 1.8 x 2.4m (4.32m2)
Tuber productivity in seed plots with different fertilizer application regimes
Results (cont’d)
0
10
20
30
40
50
60
70
80
Small Medium Large
Seed size categories
Prop
ortio
n of
tota
l tub
ers
(%)
ZeroDAP-LowDAP-HighMavuno-LowMavuno-High
Potato tuber sizes under different fertilizer application regimes
Results (cont’d)
• Seed-size (medium) tuberslow DAP & low Mavuno more than DAP-high and Mavuno Planting-high
• Ware-size (large) tubers:high DAP and high Mavuno Planting more than DAP-low and Mavuno Planting-low
No. of tubers and corresponding total tuber yield in plots without fertilizer was significantly lower than fertilized plots.
The fertilized plots did not differ significantly across all the treatments
Results (cont’d)
ConclusionThe seed-plot technology, with improved productivity through fertilizer application, can increase the availability of quality seed potato.
RecommendationThe seed-plot technology should be widely promoted, especially in smallholder farming systems where frequent replenishment of seed stocks is hampered by financial inadequacies.
Discussions/clarifications
Seed plot measurements
Estimated amount of seed to plant in a seed plot
Size of ware potato field to be covered with seed
from a seed plotWidth
(m)Length
(m)Number of
tubersWeight (kg) Acres Hectares
1.81.81.81.81.81.81.8
4.592132436486
90180420640860
12801720
6-712-1528-3543-5358-7186-106115-143
0.10.20.5
0.751
1.52
0.040.080.200.300.400.610.81
Approximate seedplot sizes to produce adequate seed tubers for ware fields
Thank you• ASARECA• KARI and other host institutions • Participating farmer groups • Organizers, 9th Triennial APA Conference• Sponsors, 9th Triennial APA Conference• The Session Participants
Z.M. Kinyua