1Past achievements and future directions of forage and pasture seed production and research for the highlands of Arsi, Ethiopia Karta K. Kalsa Kulumsa Agricultural Research Center, P.O.Box 489, Asella, Ethiopia Abstract Scarcity in varieties of well adapted forage species, shortage in seeds of highly demanded forage crops, and shortage of technical information on forage seed production have remained to be major bottlenecks in feed improvement in quality and quantity. This paper describes some findings achieved in the area of seed crop establishment and management, seed harvesting, and post harvest handling of forage and pasture crops. It also further identifies knowledge gaps on seed production and post harvest handling in potential forage species. Finally, actions are recommended for improved functioning of the forage seed production and re search system in the country. Key Words: Seed Crop, Intercropping, tropical, seed system, seed priming. Introduction Besides the slow adaptation rates by farmers to forage crops, scarcity in varieties of well adapted forage species, shortage in seeds of highly demanded forage crops, and limitations oftechnical information on forage seed production remain to be major bottlenecks in feed improvement in quality and quantity in Ethiopia. Even though the registered number ofvarieties for forage and pasture species is limited, seed productivity and seed crop management for optimum seed yield of the available varieties is rarely documented (CVR, 2010). Increasing demand for improved forage and pasture species in response to the converging grazing land area has faced seed shortage on commonly requested species such as fodder beet ( Beta vulgaris ), alfalfa ( Medicago sativa ), vetches (Vicia spp.), Rhodes grass (Chloris gayana), colored guinea grass ( Panicum coloratum), oats ( Avena sativa), etc. While forage seed production requires knowledge and skills on site selection, seed crop establishment and management, seed harvesting, post-harvest handling, and insuring of seed quality, information is limited on such issues and/or any available finding has not been well documented.
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Past achievements and future directions of forage and pasture seed
production and research for the highlands of Arsi, Ethiopia
Karta K. Kalsa
Kulumsa Agricultural Research Center, P.O.Box 489, Asella, Ethiopia
Abstract
Scarcity in varieties of well adapted forage species, shortage in seeds of highly
demanded forage crops, and shortage of technical information on forage seed
production have remained to be major bottlenecks in feed improvement in quality and
quantity. This paper describes some findings achieved in the area of seed crop
establishment and management, seed harvesting, and post harvest handling of forage
and pasture crops. It also further identifies knowledge gaps on seed production and post
harvest handling in potential forage species. Finally, actions are recommended for
improved functioning of the forage seed production and research system in the country.
Besides the slow adaptation rates by farmers to forage crops, scarcity in varieties of well
adapted forage species, shortage in seeds of highly demanded forage crops, and limitations of
technical information on forage seed production remain to be major bottlenecks in feedimprovement in quality and quantity in Ethiopia. Even though the registered number of
varieties for forage and pasture species is limited, seed productivity and seed crop
management for optimum seed yield of the available varieties is rarely documented (CVR,
2010). Increasing demand for improved forage and pasture species in response to the
converging grazing land area has faced seed shortage on commonly requested species such as
(Chloris gayana), colored guinea grass (Panicum coloratum), oats ( Avena sativa), etc. While
forage seed production requires knowledge and skills on site selection, seed cropestablishment and management, seed harvesting, post-harvest handling, and insuring of seed
quality, information is limited on such issues and/or any available finding has not been well
documented.
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At Kulumsa, forage and pasture research has been an integral component of research
activities since late 1960s. Several accessions have already been evaluated and recommended
for their adaptation areas by Chilalo Agricultural Development Unit (CADU, 1973).
Commonly recognized forage and pasture species such as alfalfa, vetches, Rhodes grass, oats,
colored guinea grass, cocksfoot, and fodder beet were amongst well evaluated species fortheir herbage productivity over several locations. While the main focus of the research during
the early period was on higher herbage yield and feed value, CADU had begun forage seed
production and research in the early 1970s. Some efforts were recorded in the areas of seed
crop establishment and management and seed harvesting and post-harvest management
certain forage and pasture species until it was discontinued in late 1980s.
Since recent years, research activities on variety evaluation for seed and herbage yield, seed
crop management, and post-harvest handling have been undertaken on selected forage and
pasture crops such as alfalfa, vetches, fodder beet, tall fescue (Festuca arundinacea), Harding
grass (Phalaris aquatic) and oats. Forage seed supply improvement has been the first priority
in the forage research and development effort at Kulumsa. Research on forage seed
production and post-harvest handling is still at its infant stage. Hence, objective of this paper
is to ascertain findings in the past, identify problem statements, and foreword future
directions for forage and pasture seed research.
Micro seed increase and distribution
Forage seed production and distribution is an integral component of the forage and pasture
research activities at Kulumsa Agricultural Research Center. In 2006/2007 about 366kg of
initial seed was produced and ca. 45% of it was distributed during the budget year to different
institutions such as Agricultural Universities, Research Centers, Farmers, Non-Governmental
organization, and Bureau of Agriculture and Rural Development from various regional states
of Ethiopia (Table 1). Seed productivity ranged from 55kg in Harding grass to 2750kg in
Tree Lucerne. In 2007/2008 a total of 4.25ha of land was covered for micro seed increase and
3154kg seed was produced. More than 80% of the seed produced the same year wasdistributed to various institutions. The largest share of total seed production is taken by oats
( Avena sativa) in both crop years.
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Table 1: Seed production and distribution status for the year 2006/2007 cropping season
Seed yielding characteristics of different forage and pasture crops
Seed yielding ability is generally affected by seed crop management practices, environment,
and genotype. Seed yield of forage crops such as alfalfa, oats, vetches, tall fescue, Harding
grass, and Rhodes grass was evaluated over locations for several years at Kulumsa. Alfalfa
varieties showed a significant variation in their seed yielding ability at Kulumsa (Table 3).
There was also variation in seed yield of varieties across seasons. Variety F-L-77 gave
highest seed yields during Belg and Meher seasons of 2005 whereas the highest seed yieldduring establishment season was registered in Sequel variety. Seed yield of all varieties in
the Meher season of 2005 was inferior as compared to the belg season of 2005. This could be
attributed to the stand age effect. Another study on seed yield performance of alfalfa
genotypes obtained from the International Livestock Research Institute (ILRI) has shown that
there is a reasonable variation among genotypes for seed yielding ability and seed yield
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components at Kulumsa (Table 4). Seed yield ability ranged from 218.4 to 1160.3kg per ha
with highest seed yield obtained from genotypes with accession numbers of ILRI7369 and
ILRI9235 gave the highest seed yield. Thousand seed weight of genotypes with superior seed
yield was smaller than that of other accessions. The two genotypes had demonstrated the
highest herbage dry matter yield such as 18755.4 and 18885.0 kg per ha, respectively(KARC, 2007).
Table 3: Seed yielding ability of alfalfa varieties over three growing seasons at Kulumsa
Forage seed production under prevailing crop culture
The crop-livestock farming system in the highlands of Arsi is part of the national cereal belt
with 73% of its cultivated area allotted to cereal production (CSA, 2009). However, the
livestock feed supply is mainly limited to crop residues and land shortage is considered by
farmers as a major bottleneck for improved forage production. To introduce forage and
pasture seed production into the existing farming system, evaluation wheat alfalfa companion
cropping was evaluated. Results showed that alfalfa seed crop can be established in
companion with dwarf and early type wheat cultivars such as KBG-01(Figure 1). Highest
alfalfa seed yield from mixed stands was obtained at 60cm row spacing. Alfalfa seed fields
have been successfully established when planted wheat at 75cm row spacing in the Middle
East (Marble, 1989). The fields are maintained as wheat field until wheat is harvested and
then as alfalfa seed fields until December. It is important to note that growing wheat with
alfalfa did not affect wheat grain yield and rather expected to increase total farm return
(Figure 2). There are important factors to consider in selecting and managing wheat as a
companion crop, including: selecting earlier maturing and shorter-stature varieties; reducing
the seeding rate; and promptly removing straw.
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Fig. 1: Effect of wheat as a companion crop on seed yield of alfalfa at Kulumsa
Fig. 2: Effect of alfalfa companion crop on wheat grain yield at Kulumsa
Fig. 3: Alfalfa intercropped with wheat cultivar
KBG-01 at Kulumsa. Wheat grain was
harvested and stubble was removed earlier when
alfalfa stands flowering.
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Fertilizer management for forage seed crops
In general, forage plants are believed to be heavy feeders and thus drain a considerable
amount of nutrients (Hazra and Sinha, 1996). In grasses the aim of fertilizing seed crops is to
synchronize production of a large number of fertile heads to get uniform ripening.
Application of nitrogen to grass seed crops is nearly always profitable since it promotes tiller
fertility (% tillers producing inflorescence) and ultimately good seed yield. Increasing
fertilizer rate up to 200kgha-1 has resulted in a rapid increase in seed yield of Rhodes grass at
the first harvest year at Kulumsa (Figure 4). Further increase in rate of urea application did
not show considerable improvement in seed yield. In the older stands seed yield was lower
than that of the first harvest but increasing fertilizer rate up to 300kgha-1 has improved seed
yield by more than 200% as compared to the unfertilized stand. Seed crops after the first
harvest require a substantial amount of N-fertilizer since nitrogen is essential to bring about
many heads and fertile spikeletes for better synchronization.
Fig. 4: Effect of rate of urea fertilizer on seed yield of Rhodes grass at different stand
ages after establishment at Kulumsa. Source: ARDU, 1983
Determination of proper time of fertilizer top dressing is an important step in fertilizer management
for seed crop. Time of urea top-dressing was studied on Rhodes grass and it observed that top-
dressing seed crop in Mid-July gave the highest clean seed and pure germinating seed yield (Figure
5). Urea top-dressing stands later than mid July continuously decreased clean seed yield as well as
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1974 1980 1983
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yield of pure germinating seed. However, urea application at any time has improved both seed yield
parameters.
Fig.5: Effect of time of urea top-dressing on clean seed yield (SY) and pure germinating
seed yield (PGS) of Rhodes grass at Kulumsa. Source: CADU, 1973.
Harvesting forage seed
Forage seed harvesting is complicated by poor synchronization of flowering/heading, seed
shattering, difficulty in attaining maximum viability at harvest. Uneven heading and seed
setting, and seed ripening of grass seed crops make the selection of harvest time difficult.
Seed harvesting on tropical grasses is usually carried out some 6-7 weeks after initial heademergence (5-10 heads plant-1) (Boonman, 1993). In Rhodes grass pure germinating seed
yield (PGS) increased until two weeks later after the first heads started to scatter the seed
(Figure 6). High clean seed yields (more that 200kgha-1) were obtained by harvesting Rhodes
grass between one and four weeks after the first heads start scattering seeds. However,
maximum clean seed yield of colored guinea grass was obtained by harvesting two weeks
later. The highest pure germinating seed yield was obtained after five weeks in colored
guinea grass. Getnet and Tadesse (1996) noted that the optimum stage of maturity for
maximum seed yield and higher viability of perennial grasses such as Rhodes grass, colored
guinea grass, and Harding grass could be obtained when harvested a month after flowering.
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Fig.6: Effect of harvesting time on seed yield of Rhodes grass and colored guinea grass.NB: CGSY and CGPGS=Colored guinea grass clean seed and pure germinating seed
yields; RSY and RPGS= Rhodes grass clean seed and pure germinating seed yields.
(Source: CADU, 1973).
Fig. 7: Beating on palm to check
scattering of first heads (Photo by
Author, 2010)
Effect of storage period and seed treatment on seed quality
Effects of adverse storage conditions on the seed vigor of various crop species have been well
documented (Hopkinson & English, 2005). When stored under prevailing temperature and
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humidity conditions, seeds of many plant species lose viability and vigor within a short
period of time; except for legume seeds with impermeable seed coats (Čupić et al., 2005).
Vigor loss is associated with biochemical losses associated during seed ageing (Murthy et al.,
2003). Seed vigor enhancement techniques such are hydro-priming are used to improve the
germination and vigor of seeds (Harris, 1996). Hydro-priming is reported to improve seedand seedling performance in soybean (Mohammadi, 2009).
Fig. 8: Speed of germination and seedling emergence index of common vetch seeds as
affected by duration of seed storage and hydro-priming. Data consists of means ±SE.
Data points followed by different letters are significantly different at α = 0.05 level of
significance. (Source: Karta et al., 2011)
Speed of germination of unprimed seeds was not affected by storing seeds for up to two years
under ambient conditions whereas emergence index has increased as seed storage duration
was increased up to two years (Figure 8). Hydro-priming significantly improved speed of
germination at all durations of storage. Emergence index was also improved by hydro-
priming common vetch seeds at zero and one year period of storage. These results are in line
with that of Mohammadi (2009), who reported that hydro-priming significantly improved
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speed of germination in soybean. Faster rate of germination of hydroprimed seeds could be
attributed to enhanced repair in the intra-cellular architecture and mobilization of hydrolytic
enzymes required for visible germination to occur (Bewley, 1997).
Problems in forage seed production and research
Problems in forage seed production
Limited number of varieties commercially registered
Shortage of locally adaptable technical information on establishment, seed
crop management, seed harvesting, cleaning, packing, and storage
Evolutionary problems such as poor seed yielding ability, seed shattering,
dormancy.
Unpredictable demand for forage seed and low priority by farmers to
cultivated forage, and weak forage seed marketing Problems in forage seed research
Priority to herbage productivity and quality improvement
Limited skill in forage breeding, agronomic management of seed crops for
seed yield and quality improvement
Limited facility for post-harvest handling research
Future directions in forage seed production and research
Forage crop improvement Data collection should consider traits associated with optimum seed yield and
quality, but without significantly affecting herbage yield and quality
Focus should be place on limited number of species with wide adaptation for
seed as well as herbage production
Forage seed agronomy
Information on seed crop establishment (seed rate, fertilizer rate, dormancy
breaking, seed enhancement, etc) should be generated for species with wider
adaptation and superior herbage yield and quality
Seed crop management (stand management for perennials, harvesting stages
and harvesting methods)
Post harvest handling
Seed cleaning and packing techniques, storage regime, duration of storage,
Čupić, T, Popović, S., Grljušić,time on alfalfa seed quality. J. C.
CVR (Crop Variety Register). 2Development, Addis Ababa, Eth
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d value chain and networking stakeholders (Fi
networking key players in the forage seed va
dations
e area of seed crop establishment and managem
ling of forage and pasture crops. However, the
n and post harvest handling in potential forage
ist in the area of forage seed production and res
ve to be taken into consideration for improved f
search system in the country.
Unit).1983. Report on survey and experimenta
ion and dormancy. The Plant Cell. 9:1055-106
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ty). 2009. Report on Farm Management PracticEthiopia Central Statistical Agency, Agricultur
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09. Crop variety register. Ministry of Agricultuiopia.
ure 9)
lue chain
ent, seed
e still is
species.
earch.
unctioning of
l results.
.
xperimental
s. Thel Sample
ct of storage
re and Rural
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