Effects of Field Weathering on Seed Quality of Cowpea (Vigna Unguiculata) PDF Download

Author: Patsy Worrell
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ISBN:
Category : Cowpea
Languages : en
Pages : 104

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Author: Patsy Worrell
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Category :
Languages : en
Pages : 52

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Author: Edson Herculano Neves Vieira
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ISBN:
Category : Cowpea
Languages : en
Pages : 172

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Field and laboratory experiments were conducted to evaluate the relationship between seed specific gravity, and/or seed density, to the phydiological quality, storability and seedling performance of cowpea seeds. Two methods of seed separation were used: a) separation using aqueous sucrose and b) using a table model fractionating aspirator. Seeds of different specific gravity separated by sucrose solution were compares using a standard germination test at 20-30oC and accelerated aging tests at temperatures of 40oC, 42oC, and 45oC for 48 and 72 hours. Germination responses indicated that low specific gravity seeds perform poorly when compared to high specific seeds and to the unseparated sample. However, seed vigor responses expressed by the accelerated tests results revealed significantly higher vigor for the unseparated sample than for any of the specific gravity classes, suggesting that the use of aqueous solutions for cowpea seed separation may have a detrimental effect on seed quality possibly due to water absorption during separation. Field emergence results in 1988 were not significantly different among specific gravity categories. In 1990, field emergence responses were similar to results obtained in the accelerated aging tests. The unseparated seeds were superior to the seeds which were separated using solutions. However, differences in yield in both 1988 and 1990 planting seasons were not related to seed specific gravity. The evaluation of the relationship between seed density expressed by 100 seed weight and storability of cowpea seeds was determined different density fractions obtained using a fractionating aspirator. Evaluations were conducted prior to storage and after 6, 9 and 12 months of open storage using the standard germination test, first count germination, accelerated aging test, and germination performance at low temperature. Vigor was also evaluated by comparing seedling elongation characteristics. No significant differents were observed in germination percentage for all categories prior to storage. However, tests conducted after each storage period revealed significantly higher germination for the high density seeds as well as for the unseparated control.

Author: Neville McAndrew
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Category : Cowpea
Languages : en
Pages :

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Author: VIJAYABHASKAR N
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Category :
Languages : en
Pages : 146

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Author: Thammasak Thongket
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Category : Cowpea
Languages : en
Pages : 154

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Author: E. H. N. Vieira
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Category :
Languages : en
Pages : 86

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Field and laboratory experiments were conducted to evaluate the effects of seed specific gravity, and/or seed density, on physiological quality, storability and seedling performance of cowpea (Vigna unguiculata (L.) Walp) seeds. Seed preparation was accomplished by two methods: using aqueous sucrose solutions and by means of a table model fractionating aspirator.

Author: RAVINDRA
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Category :
Languages : en
Pages : 87

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Author: GANAGER TAMMANNA S
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Languages : en
Pages : 113

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Author: An-Ching Cheng Tang
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Category : Cowpea
Languages : en
Pages : 290

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Seed yields of 'Texas Cream 40' and 'Pinkeye Purple Hull' cow peas were significantly reduced when seeds were produced under high temperature, drought stress, low light intensity, or deficient levels of N or P in the growth media, but were unaffected by variation in photo period. Seed vigor of either cultivar was unaffected by photo period or light intensity. Hard-seededness developed in 'Pinkeye Purple Hull' under shortdays. Drought stress of -4 or -8 bars during seed development reduced subsequent seedling axis growth of 'Texas Cream 40' compared to a nonstressed treatment. At seed maturity smaller embryo size and less nutrient accumulation, especially starch, in the cotyledons accounted for this reduction in seed vigor. Under similar conditions, 'Pinkeye Purple Hull' produced seeds as vigorous as the unstressed control. At day/night temperatures of 28°/20°C and 33°/25°C, seeds of both cultivars had higher vigor characteristics than seeds which developed at 38°/30°C or 23°/15°C. In 'Texas Cream 40', heat stress at 38°/30°C appeared to reduce the ability of seedlings to utilize food reserves effectively during germination. Reduced seed vigor of 'Pinkeye Purple Hull' at 38 /30 C was related to a shortage of reserve food, especially starch, at seed maturity. Vigor of seeds of both cultivars produced at 23 /15 C was less than seeds produced at 28°/20°C and 33°/25°C but was not as reduced as those produced at 38°/30°C. In nutritional experiments, seed vigor of 'Texas Cream 40' was unaffected by various nutritional treatments imposed from sowing to seed maturity. 'Pinkeye Purple Hull' plants grown on a deficient level of N, P or S had reduced seed vigor compared with those grown in complete Hoagland's solution. Seed vigor of this cultivar was also reduced by doubling the N level in the nutrient media. When imposed after anthesis, increased N and P levels in the nutrient media of the parent plant did not alter seed vigor of either cultivar. However, reducing N or P levels to one-quarter of those in a complete Hoagland's solution enhanced axis growth of the progenies of both cultivars.