Effects of phosphorus nutrition on growth, fruit abscission and seed yield of the cowpea(Vigna unguiculata L.)

Studies on genetic variability, correlation and path coefficient analysis were carried out with 38 accessions of cowpea (Vigna unguiculata L. Walp.) evaluated in two environments i. e. kharif 2013 (E1) and kharif 2014 (E2) at Research field of NBPGR, Regional Station Jodhpur, India. Analysis of variance revealed significant differences among the genotypes for all the traits. Genotypic coefficient of variation was highest for number of clusters per plant followed by number of pods per plant in both the environments. High broad sense heritability along with high genetic advance for seed yield per plant, 100 seed weight, pod length, number of pods per plant, peduncle length, number of clusters per plant, number of branches per plant and plant height indicated the presence of additive gene effects for these traits in cowpea. In both the environments seed yield per plant was positively correlated with 100 seed weight, pod length, number of pods per plant, number of clusters per plant, number of branches per plant and plant height. The highest positive direct effect registered by number of branches per plant followed by number of clusters per plant in E1 environment and by number of branches per plant followed by plant height in E2 environment. The traits like 100 seed weight, plant height, number of pods per plant number of clusters per plant and number of branches per plant were identified as selection criteria for obtaining good parental lines in cowpea breeding programmes.

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Effect of Weeds on Pre-flowering Insect Infestation and Seed Yield of Cowpea (Vigna unguiculata) in a Rainforest Area of Nigeria

Experimental Agriculture ◽

10.1017/s001447970001485x ◽

1989 ◽

Vol 25 (3) ◽

pp. 343-347 ◽

Cited By ~ 3

Author(s):

Tom I. Ofuya

Keyword(s):

Seed Yield ◽

Vigna Unguiculata ◽

Insect Infestation ◽

Insect Populations ◽

Empoasca Dolichi ◽

Ootheca Mutabilis

SUMMARYPre-flowering insect infestation of cowpea, Vigna unguiculata, was monitored in weedy and weed-free plots in 1986 and 1987 in Akure, Nigeria. Weediness generally reduced infestations of both the leafhopper, Empoasca dolichi, and the flea beatle, Ootheca mutabilis. However, seed yield was reduced in the weedy plots despite heavier pre-flowering insect populations in the plots kept weed-free.

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The role of vesicular-arbuscular mycorrhizas (VAM) in the phosphorus nutrition of cowpea (Vigna unguiculata (L.) Walp)

Australian Journal of Agricultural Research ◽

10.1071/ar9910129 ◽

1991 ◽

Vol 42 (1) ◽

pp. 129 ◽

Cited By ~ 3

Author(s):

BM Ikombo ◽

DG Edwards ◽

CJ Asher

Keyword(s):

Vigna Unguiculata ◽

Phosphorus Deficiency ◽

Phosphorus Nutrition ◽

Strong Increase ◽

Phosphorus Concentration ◽

Sequence Of Events ◽

Mycorrhizal Association ◽

Low Phosphorus ◽

Unsterilized Soil

An experiment was conducted to establish the role of VAM in the phosphorus nutrition and early growth of cowpea (Vigna unguiculata (L.) Walp.) cv. Vita 4 in a podzolic soil (Haplustult). The experiment involved four treatments: (1) plants grown in unsterilized soil adequately supplied with phosphorus (240 kg P ha-1), (2) plants grown in unsterilized soil with low phosphorus (10 kg P ha-1), (3) and (4) plants grown in methyl bromide sterilized soil with low phosphorus (10 kg P ha-1). Plants in treatments (1), (2) and (3) were inoculated with Bradyrhizobium. A series of harvests was taken from 14 to 42 days after sowing; 15 harvests at two-day intervals from treatment (2) and 5 harvests at 7-day intervals from the other treatments. Root infection by VAM did not occur in plants grown in the sterilized soil treatments (3) and (4); growth of these plants was poor, and they showed symptoms of severe phosphorus deficiency. Phosphorus concentrations in the youngest fully expanded leaf (YFEL) of plants grown in treatments (3) and (4) were in the range 0.10 to 0.16% at all harvests. Plants which were grown in the unsterilized soil with 240 kg P ha-l (treatment (1)) grew very well; they had a high concentration of phosphorus (0.3 1 to 0.75%) in the YFEL at all harvests and exhibited a delayed and reduced level of infection by VAM. Plants grown in the unsterilized soil with 10 kg P ha-l (treatment (2)) were strongly colonized by VAM; infection was apparent at 14 days after sowing and reached a maximum (85% of root segments colonized) at 36 days after sowing. A strong increase in phosphorus concentration in the YFEL of plants grown in treatment (2) commenced at 22 days after sowing, while an increase in dry matter yield and phosphorus content of the whole tops above that of non-mycorrhizal plants grown in the sterilized soil was observed at 30 days after sowing. The sequence of events leads us to conclude that the recovery of cowpea plants from early phosphorus deficiency stress resulted from increased phosphorus absorption following the development of a mycorrhizal association with the roots.

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