Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Role of Environment During Seed Development on Subsequent Seed Quality of Cowpea (Vigna Unguiculata)
Author: The Role of Environment During Seed Development on Subsequent Seed Quality of Cowpea (Vigna Unguiculata)
Author: An-Ching Cheng TangPublisher:
ISBN:
Category : Cowpea
Languages : en
Pages : 290
Book Description
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.
Assessing successive leaf yield performance of dual-purpose cowpea (Vigna unguiculata) to decrease seasonal shortage of nutrients in resource-poor small-scale households of Tanzania and Uganda
Author: Severin PolreichPublisher: Cuvillier Verlag
ISBN: 3736937008
Category : Science
Languages : en
Pages : 170
Book Description
This study presents a method to assess yield performance of dual-purpose cowpea types for human consumption and to reveal potentials for further improvement of its use as leafy vegetable. Eleven cowpea accessions with different genetic background and sample status were chosen from AVRDC’s working collection in Arusha, Tanzania. Among them, dual-purpose cowpeas like Dakawa, Ex Iseke and Ngoji were present that the center has been distributing to local farmers. Multi-location trials in typical cowpea production environments were established both on farm and on station in the regions Arusha, Dodoma, and Kilimanjaro in Tanzania and in Eastern Region, Uganda during the short and long rainy season 2007 and 2008, respectively. Young, tender leaves were picked in successive leaf harvests about every and two weeks until the plants did not produce further leaves. Cowpea seeds were harvested when pods reached 80% maturity. Data of yield parameters were analyzed with analysis of variance (ANOVA), stability analyses were carried out according to the dynamic and static concepts. Reliability of leaf and seed yield performances were calculated based on the probability of outperformance of local check cowpeas that were previously recommended by farmers and extension workers in informal group sessions. Through NIRS, crude protein and iron contents were assessed in leaves obtained from the second leaf harvests at the different locations and from up to subsequent leaf harvests. Dual-purpose utility for smallholders was assessed through (i) an index of superiority (Si), in which reliabilities of leaf yield across repeated leaf harvests and seed yield were weighed and combined to overall yield benefit of the ith accession, (ii) effective plot length for nutritional component XY, to calculate the length of a plot (in m) that needs to be planted to sustain a five-head household for ten days with a recommended amount of nutrients, and (iii) responsiveness (Resp), reflecting changes of leaf yield (compensation) relative to changes in seed yield (sensitiveness) if harvesting frequency was intensified. Performance of single leaf yields was strongly influenced by environmental factors and, only in Arusha, accession-specific. Interactions between yield reliability and stability were site-specific. Overall, test-accessions achieved higher reliabilities in seed yield than in leaf yield. Only in the on-station trial in Eastern Region, accession IT82D-889, and in the on-farm trial in Kilimanjaro, ILRI11114 and Ex Iseke showed leaf yield reliabilities above 0.50. Iron content in cowpea leaves was highly dependent on environmental influences and varied from 157.4 mg kg-1 to 286.1 mg kg-1. Leaf CP had a broad-sense heritability of 0.87. Across accessions and environments the mean leaf CP content ranged from 37.4% of DM (IT93K-2045-29) to 33.9% of DM (Sudan). CP and leaf dry matter (DM) yield had significantly negative correlation coefficients between. Means of effective plot length for crude protein and iron varied by more than 50% across environments. Although CP, in contrast to iron, was genetically determined, its impact on differences in effective plot length was negligible as well, as differences in production of leaf DM per m2 were by far larger among accessions than those of CP contents. It was recommended to favor accessions with short effective plot lengths and higher CP contents in leaf yields over those with short effective plot lengths and low CP contents. In contrast to determinate cowpeas, indeterminate types increased their DM gain in aerial plant parts of leaf-harvested plants relatively to unharvested plants. Indeterminate cowpeas responded with high leaf yield increases if leaves were picked twice a week. Consequently yields of total edible DM of these plant types, comprising added seed and leaf yields, increased with intensification of leaf-harvesting frequency from once to twice a week. Determinate plant types yielded highest in total edible DM when only seed was harvested or in less intensive leaf-harvesting scenarios. Accessions with favorable responsiveness, reflecting leaf yield changes relative to seed yield changes under intensified leaf-harvesting frequency, were Sudan, ILRI11114, and IT93K2045-29. In contrast, Resps of SAM45 and ILRI15742 were poorest. Traits have to be identified that could explicitly improve Resp of cowpea types. Improving quantitative yield parameters should not result in quality decrease. The dual-purpose characteristics of local checks were mainly superior to the eleven test-accessions pointing to a demand on improved leaf yield performance that is not merely total leaf yield amount but also the continuance during repeated leaf harvesting. By the proposed method the status quo of a defined location, i.e. site-specific demands on germplasm, can be included in the analysis, serving as benchmark for improvement if the local check is chosen carefully. Since single leaf yields are the results of fairly complex and dynamic interactions between plant physiological processes and environmental conditions it is essential to conduct participatory variety selection and plant breeding trials for dual-purpose assessments in target environments and not ex situ.
Basic and Applied Aspects of Seed Biology
Author: R.H. EllisPublisher: Springer Science & Business Media
ISBN: 9401157162
Category : Science
Languages : en
Pages : 808
Book Description
The Fifth International Workshop on Seeds was held at the University of Reading, UK, from 10 to 15 September, 1995. Some 230 seed scientists, from a wide range of disciplines (botanists, biochemists, ecologists, agriculturalists, foresters, and commercial seedsmen), from 31 countries (Europe, the Americas, and Asia) participated in the workshop. A large number of oral and poster presentations was made during the workshop and we are pleased to publish so many of them in these Proceedings. The papers herein are listed by the sessions in which they were presented but, as is often the case, many papers cover a broader range of topics than the session titles imply. For seed physiologists, ecologists, and technologists, this book collates much of the current research on seeds.
Dissertation Abstracts International
Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 830
Book Description
American Doctoral Dissertations
Author: Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 776
Book Description
Relationship Between Seed Density and Quality of Cowpea (Vigna Unguiculata (L.) Walp) Seeds
Author: Edson Herculano Neves VieiraPublisher:
ISBN:
Category : Cowpea
Languages : en
Pages : 172
Book Description
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.
Comprehensive Dissertation Index
Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 752
Book Description
Effect of Plant Growth Regulators on Growth, Yield and Seed Quality in Cowpea (Vigna Unguiculata (L.) Walp)
Author: GANAGER TAMMANNA SEffects of Field Weathering on Seed Quality of Cowpea (Vigna Unguiculata)
Author: Patsy WorrellPublisher:
ISBN:
Category : Cowpea
Languages : en
Pages : 104
Book Description