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Selection of Novel Cowpea Genotypes Derived through Gamma Irradiation.

Horn LN, Ghebrehiwot HM, Shimelis HA - Front Plant Sci (2016)

Bottom Line: Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought.Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors.The selected promising mutants' lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments.

View Article: PubMed Central - PubMed

Affiliation: School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-NatalPietermaritzburg, South Africa; Directorate of Research and Training, Plant Production Research, Ministry of Agriculture, Water and ForestryWindhoek, Namibia.

ABSTRACT
Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought. Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors. The objective of this study was to identify agronomically desirable cowpea genotypes after mutagenesis using gamma irradiation. Seeds of three traditional cowpea varieties widely grown in Namibia including Nakare (IT81D-985), Shindimba (IT89KD-245-1), and Bira (IT87D-453-2) were gamma irradiated with varied doses and desirable mutants were selected from M2 through M6 generations. Substantial genetic variability was detected among cowpea genotypes after mutagenesis across generations including in flowering ability, maturity, flower and seed colors and grain yields. Ten phenotypically and agronomically stable novel mutants were isolated at the M6 each from the genetic background of the above three varieties. The selected promising mutants' lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments. The novel cowpea genotypes selected through the study are valuable genetic resources for genetic enhancement and breeding.

No MeSH data available.


Variation among Shindimba mutant lines. (A) coiled pods, (B) semi-coiled pods observed at Mannheim during the M2 generation, (C) white flower with semi-coiled pods, and (D) Purple flowers observed at Omahenene during the M5 generation.
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Figure 5: Variation among Shindimba mutant lines. (A) coiled pods, (B) semi-coiled pods observed at Mannheim during the M2 generation, (C) white flower with semi-coiled pods, and (D) Purple flowers observed at Omahenene during the M5 generation.

Mentions: Variable number of individual plants was available for selection during M3 to M5 generations, because of the strength of irradiation treatment and segregation. The following doses allowed successful selections of mutants during the M3 to M5: 300, 450, and 600 Gy (Bira), 100 and 150 Gy (Nakare), and 100 and 200 Gy (Shindimba). Surviving and phenotypically stable individuals were advanced at each selection generation at Omahenene and Bagani Research Stations. Qualitative traits had limited variation during M3 to M5 (Table 3). Bira mutants displayed purple FC irrespective of doses and test generations, while Nakare and Shindimba segregated for white and purple FC (Figures 3 and 5). Both Bira and Nakare mutants had straight PS similar to the controls. However, Shindimba segregants had straight and coiled pod types (Figure 5). Variable SCs including white, brown, red, cream, speckled, chocolate, light and dark brown, black and mixed were observed during the M3 to M5. Bira mutants had smooth SCT, while Nakare and Shindimba had mainly rough and smooth seed texture. Bushy, erect and spreading GHs were detected during the M3 to M5 (Figures 3 and 5).


Selection of Novel Cowpea Genotypes Derived through Gamma Irradiation.

Horn LN, Ghebrehiwot HM, Shimelis HA - Front Plant Sci (2016)

Variation among Shindimba mutant lines. (A) coiled pods, (B) semi-coiled pods observed at Mannheim during the M2 generation, (C) white flower with semi-coiled pods, and (D) Purple flowers observed at Omahenene during the M5 generation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834446&req=5

Figure 5: Variation among Shindimba mutant lines. (A) coiled pods, (B) semi-coiled pods observed at Mannheim during the M2 generation, (C) white flower with semi-coiled pods, and (D) Purple flowers observed at Omahenene during the M5 generation.
Mentions: Variable number of individual plants was available for selection during M3 to M5 generations, because of the strength of irradiation treatment and segregation. The following doses allowed successful selections of mutants during the M3 to M5: 300, 450, and 600 Gy (Bira), 100 and 150 Gy (Nakare), and 100 and 200 Gy (Shindimba). Surviving and phenotypically stable individuals were advanced at each selection generation at Omahenene and Bagani Research Stations. Qualitative traits had limited variation during M3 to M5 (Table 3). Bira mutants displayed purple FC irrespective of doses and test generations, while Nakare and Shindimba segregated for white and purple FC (Figures 3 and 5). Both Bira and Nakare mutants had straight PS similar to the controls. However, Shindimba segregants had straight and coiled pod types (Figure 5). Variable SCs including white, brown, red, cream, speckled, chocolate, light and dark brown, black and mixed were observed during the M3 to M5. Bira mutants had smooth SCT, while Nakare and Shindimba had mainly rough and smooth seed texture. Bushy, erect and spreading GHs were detected during the M3 to M5 (Figures 3 and 5).

Bottom Line: Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought.Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors.The selected promising mutants' lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments.

View Article: PubMed Central - PubMed

Affiliation: School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-NatalPietermaritzburg, South Africa; Directorate of Research and Training, Plant Production Research, Ministry of Agriculture, Water and ForestryWindhoek, Namibia.

ABSTRACT
Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought. Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors. The objective of this study was to identify agronomically desirable cowpea genotypes after mutagenesis using gamma irradiation. Seeds of three traditional cowpea varieties widely grown in Namibia including Nakare (IT81D-985), Shindimba (IT89KD-245-1), and Bira (IT87D-453-2) were gamma irradiated with varied doses and desirable mutants were selected from M2 through M6 generations. Substantial genetic variability was detected among cowpea genotypes after mutagenesis across generations including in flowering ability, maturity, flower and seed colors and grain yields. Ten phenotypically and agronomically stable novel mutants were isolated at the M6 each from the genetic background of the above three varieties. The selected promising mutants' lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments. The novel cowpea genotypes selected through the study are valuable genetic resources for genetic enhancement and breeding.

No MeSH data available.