scholarly journals Experimental studies on seed production of tropical grasses in Kenya. 3. The effect of nitrogen and row width on seed crops of Setaria sphacelata cv. Nandi II.

1972 ◽  
Vol 20 (1) ◽  
pp. 22-34
Author(s):  
J.G. Boonman
Keyword(s):  
Seed Production ◽  
Experimental Studies ◽  
Rapid Decline ◽  
Tropical Grasses ◽  
Seed Crop ◽  
Row Width ◽  
Setaria Sphacelata ◽  
Seed Crops ◽  
Germinable Seed

Setaria sphacelata sown broadcast or in rows up to 100 cm apart was given 0-260 kg N/ha applied to each seed crop. 100 kg N/ha increased herbage DM yields 3-fold and yields of germinable seed 7-fold. At 130 kg N/ha yields of germinable seed were 33% higher from rows 30 cm apart than from rows 90 cm apart. Percentage and yield of germinable seed varied very greatly between seasons, though DM yield and inflorescence number varied little. The highest yield of germinable seed was 48 kg/ha for a single harvest. Rapid heading was preceded by a rapid increase and a subsequent rapid decline in tiller numbers. Herbage DM response to 100 kg N was 65 kg DM/kg N. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Experimental studies on seed production tropical grasses in Kenya. 6. The effect of harvest date on seed yield in varieties of Setaria sphacelata, Chloris gayana and Panicum coloratum.

1973 ◽  
Vol 21 (1) ◽  
pp. 3-11
Author(s):  
J.G. Boonman
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Experimental Studies ◽  
The Other ◽  
Harvest Date ◽  
Tropical Grasses ◽  
Panicum Coloratum ◽  
Setaria Sphacelata ◽  
Chloris Gayana ◽  
Late Abstract

Setaria sphacelata cv. Nandi I and Nandi III, Chloris gayana cv. Mbarara, Masaba and Pokot, and Panicum coloratum cv. Solai were grown for seed and harvested on a range of dates beginning 3-4 weeks after initial head emergence (defined as 5-10 heads/m2). Harvesting date was not very critical, and harvesting could normally be spread over 1-2 weeks. The interval between initial heading and optimum harvest date was normally 6-7 weeks. In most crops considerable shedding of spikelets (up to 30-50% in P. coloratum, rather less in the other 2 species) could be tolerated before yield of pure germinating seed fell with delay in harvesting. It was suggested that most of the spikelets which were shed early were empty. Cultivars which headed early produced nearly twice as much seed as those which headed late. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Experimental studies on seed production of tropical grasses in Kenya. 5. The effect of time of nitrogen top dressing on seed crops of Setaria sphacelata cv. Nandi.

1972 ◽  
Vol 20 (4) ◽  
pp. 225-231
Author(s):  
J.G. Boonman
Keyword(s):  
Adverse Effect ◽  
Seed Production ◽  
Rainy Season ◽  
Seed Set ◽  
Experimental Studies ◽  
Late Season ◽  
Main Adverse Effect ◽  
Setaria Sphacelata ◽  
Seed Crops ◽  
Seed Yields

Effects of date of applying top-dressings of N to early-season and late-season seed crops of Setaria sphacelata cv. Nandi were studied in 4 trials in 1967-71. Highest seed yields were obtained when N was applied as soon as possible after the onset of the rainy season; a delay of 4 weeks reduced yields of pure germinating seed by >60%. Total yields of herbage DM and number of heads were also reduced, but to a lesser extent; the main adverse effect was on seed set/head. In late-season crops, applying N 2 weeks after the earliest possible date proved beneficial in 2 out of 3 years. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Experimental studies on seed production of tropical grasses in Kenya. 1. General introduction and analysis of problems.

1971 ◽  
Vol 19 (1) ◽  
pp. 23-36
Author(s):  
J.G. Boonman
Keyword(s):  
Seed Production ◽  
Seed Set ◽  
Experimental Studies ◽  
General Introduction ◽  
Tropical Grasses ◽  
Melinis Minutiflora ◽  
Brachiaria Ruziziensis ◽  
Seed Retention ◽  
Setaria Sphacelata ◽  
Chloris Gayana

Problems in seed production of Setaria sphacelata (2 cv.), Chloris gayana (3 cv.), Panicum coloration, P. maximum, Brachiaria ruziziensis and Melinis minutiflora are discussed. Low yields and quality were due to varying combinations of prolonged heading season per plant and per cultivar, prolonged flowering within a given head, low seed set, low number of fertile tillers, low seed retention, disease and bird damage. Actual yields were only about 5% of potential yields.-R.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Effects of water and nitrogen on seed production of creeping red fescue

2008 ◽  
Vol 88 (3) ◽  
pp. 439-446 ◽  
Author(s):  
N. A. Fairey
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
N Fertilization ◽  
Festuca Rubra ◽  
Seed Crop ◽  
Red Fescue ◽  
Peace River ◽  
River Region ◽  
Seed Crops

In order to address a paucity of information, a study was conducted in the Peace River region of northwestern Canada to determine the effects on seed production of creeping red fescue (Festuca rubra L. var. rubra) of six water treatments [natural precipitation and 100, 125, 150, 175 and 200% of the average, cumulative, long-term precipitation (LTP) of 459 mm yr-1] in combination with four N-fertilization regimes (zero + 102, 34 + 68, 68 + 34, and 102 + zero kg ha-1 N for the first + second crops, respectively). The 2-yr seed yield exceeded 2900 kg ha-1 when N was supplied to just one of the two seed crops, viz. with 150 to 200% LTP when N was applied only to the first seed crop, and with 125 to 150% LTP when N was applied only to the second seed crop. Under the prevailing, long-term, moisture environment at the study site (100% LTP), total seed yield over two production years was greatest (2136 kg ha-1) with 68 + 34 kg ha-1 N. The effects of the water and N treatments on seed yield were not associated with the mass of root organic matter recovered after the harvest of the second seed crop. These results confirm, and begin to quantify, numerous visual observations in the Peace River region that seed yields of creeping red fescue are restricted by insufficient precipitation. Key words: Creeping red fescue, Festuca rubra, grass seed production, nitrogen fertility, water, soil moisture

scholarly journals Experimental studies on seed production of tropical grasses in Kenya. 2. Tillering and heading in seed crops of eight grasses.

1971 ◽  
Vol 19 (4) ◽  
pp. 237-249
Author(s):  
J.G. Boonman
Keyword(s):  
Seed Yield ◽  
Experimental Studies ◽  
First Year ◽  
Panicum Maximum ◽  
Linear Rate ◽  
Brachiaria Ruziziensis ◽  
Setaria Sphacelata ◽  
Chloris Gayana ◽  
Seed Crops ◽  
Seed Yields

Tillering in seed crops grown undisturbed for 6 months was studied over 2 years in cultivars of Setaria sphacelata, Chloris gayana, Panicum coloratum, Panicum maximum and Brachiaria ruziziensis. Tiller numbers rose to a maximum around the time of initial head emergence (5-10 heads/m2), followed by a decline and finally a levelling off. Head emergence was found to continue in some cv. for over 3 months. The weight/tiller increased at a linear rate. Tiller numbers never exceeded 1900/m2. Tillers were less numerous but were heavier in the year of sowing than in the subsequent year. Total dry weights of tillers were also highest in the first year. Seed yield was significantly correlated with degree of concentrated head emergence and percentage of heading tillers in a cultivar. It is suggested that, within cv., plants with heavier tillers may produce higher seed yields. Cv. within species can be identified according to date of initial head emergence. A type of culm branching is described in which tillers develop into flowering culms out of elevated nodes of erect parental culms. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Experimental studies on seed production of tropical grasses in Kenya. 4. The effect of fertilizer and planting density on Chloris gayana cv. Mbarara.

1972 ◽  
Vol 20 (3) ◽  
pp. 218-224
Author(s):  
J.G. Boonman
Keyword(s):  
Seed Yield ◽  
Crop Yields ◽  
Experimental Studies ◽  
Planting Density ◽  
Rhodes Grass ◽  
Clean Seed ◽  
Chloris Gayana ◽  
Seed Crops ◽  
Seed Yields ◽  
Germinable Seed

Rhodes grass sown broadcast or in rows 25-100 cm apart at 0.2-1.8 kg pure germinable seed/ha was given 0-80 kg seedbed P2O5 and 0-200 kg N/ha for each seed crop. Yields of DM in the establishment year were significantly higher at high seed rates and close spacing, whereas yields of clean seed were decreased from 145 kg/ha (50-cm rows) at the lowest seed rate to 110 kg/ha at the highest. Seed yields were highest, 160 kg/ha, from broadcast sowings at 1 kg/ha. Yields of pure germinable seed were not significantly affected by treatment. In 6 seed crops taken after establishment, the only factor of importance for seed yield was N; yields of pure germinable seed increased from 6.2 kg/ha without N to 36.7-41.0 kg/ha at 100 kg N/ha and 41.2-43.2 kg/ha at 150 kg N/ha. DM yields from these 6 crops were higher at the wider row spacings. Increased N and wider spacing accelerated the onset of heading. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Experimental studies on seed production of tropical grasses in Kenya 7. The breeding for improved seed and herbage productivity.

1973 ◽  
Vol 21 (1) ◽  
pp. 12-23
Author(s):  
J.G. Boonman ◽  
A.J.B. van Wijk
Keyword(s):  
Seed Production ◽  
Experimental Studies ◽  
Tropical Grasses ◽  
Breeding Work

The history and characteristics of the Kitale varieties of Setaria, Chloris, Panicum and Brachiaria are described, as are seed multiplication practices and current breeding work. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Sugar beet seed production and marketing in the United Kingdom

1975 ◽  
Vol 8 (5) ◽  
pp. 284-289
Keyword(s):  
United Kingdom ◽  
Sugar Beet ◽  
Seed Production ◽  
The United Kingdom ◽  
Seed Crops ◽  
The Impact

Sugar beet differs from most other farm seed crops, in that “varieties” are mixtures of hybrids from a blend of genotypes. Growing and processing are two equally important aspects of seed production. In this article, cultural and harvesting methods are described, and processing and marketing procedures are briefly outlined. The impact of EEC regulations affecting seeds is also considered.

scholarly journals Researches on the Main Characteristics of Red Clover Seedlings and their Influence in

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Marioara GREBENIȘAN ◽  
Doru PAMFIL ◽  
Dorottya Alice DOMOKOS
Keyword(s):  
Plant Breeding ◽  
Seed Production ◽  
Red Clover ◽  
Production Level ◽  
Seed Crop ◽  
Binding Process ◽  
Lower Variability ◽  
Clover Seed ◽  
Number Of Seeds

Concerning the red clover breeding, it is essential to choose as genitors those varieties that possess good characteristics. In order to identify potential genitors, two red clover varieties were studied at Cluj-Napoca: Roxana, diploid variety and Napoca-tetra, tetraploid variety. The analyzed traits comprised the number of capitula/plant, number of seeds/capitulum and the binding process, under the aspect of their contribution to the seed crop and the interaction between those components, in order to provide important clues about di-and tetraploid red clover seed production, for plant breeding. The highest variability (s%=30) presented regarding the number of flowers/capitulum, diploid variety comparatively with a lower variability (s%=26) regarding the number of flowers number/capitulum, tetraploid varieties. Several traits were compared between di-and tetraploid red clover varieties in order to find genitors which can be used for creating new genotypes with high seed production level.

scholarly journals First Report of Iris yellow spot virus on Onion and Leek in Western Oregon

Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 468-468 ◽  
Author(s):  
D. H. Gent ◽  
R. R. Martin ◽  
C. M. Ocamb
Keyword(s):  
United States ◽  
Disease Incidence ◽  
The United States ◽  
Yellow Spot ◽  
Onion Bulb ◽  
Spot Virus ◽  
First Report ◽  
Seed Crop ◽  
Onion Seed ◽  
Seed Crops

Onion (Allium cepa) and leek (Allium porrum) are grown on approximately 600 ha in western Oregon annually for bulb and seed production. During July and August of 2006, surveys of onion bulb crops and onion and leek seed crops in western Oregon found plants with symptoms of elongated to diamond-shaped, straw-colored lesions characteristic of those caused by Iris yellow spot virus (IYSV) (1–4). Symptomatic plants were collected from fields of an onion bulb crop, an onion seed crop, and two leek seed crops located in Marion County. The onion bulb crop had been planted in the spring of 2006, and the onion and leek seed crops had been planted in the fall of 2005, all direct seeded. Cultivar names were not provided for proprietary purposes. Symptomatic plants in the onion bulb crop and leek seed crop generally were found near the borders of the field. Disease incidence was less than 5% and yield losses in these crops appeared to be negligible. In the onion seed crop, symptomatic plants were found throughout the field and disease incidence was approximately 20%. Approximately 1% of the onion plants in this field had large necrotic lesions that caused the seed stalks (scapes) to lodge. The presence of IYSV was confirmed from symptomatic leaves and scapes by ELISA (Agdia Inc., Elkhart, IN) using antiserum specific to IYSV. RNA was extracted from symptomatic areas of onion leaves and scapes, and a portion of the nucleocapsid gene was amplified by reverse transcription-PCR. The amplicons were sequenced and found to share more than 99% nucleotide and amino acid sequence identity with an onion isolate of IYSV from the Imperial Valley of California (GenBank Accession No. DQ233475). In the Pacific Northwest region of the United States, IYSV has been confirmed in the semi-arid regions of central Oregon (1), central Washington (2), and the Treasure Valley of eastern Oregon and southwest Idaho (3). To our knowledge, this is the first report of the disease on a host crop in the mild, maritime region west of the Cascade Mountain Range and the first report of IYSV on leek seed crops in the United States, which complements a simultaneous report of IYSV on commercial leek in Colorado. The presence of IYSV may have implications for the iris and other ornamental bulb industries in western Oregon and western Washington. This report underscores the need for further research to determine the impact of the disease on allium crops and other hosts and the development of effective management programs for IYSV and the vector, Thrips tabaci. References: (1) F. J. Crowe and H. R. Pappu. Plant Dis. 89:105, 2005. (2) L. J. du Toit et al. Plant Dis. 88:222, 2004. (3) J. M. Hall et al. Plant Dis. 77:952, 1993. (4) H. F. Schwartz et al. Plant Dis. 91:113, 2007.

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