Cytology and leafspot resistance in Arachis hypogaea x wild species hybrids

Company, M. and Stalker, H.T. and Wynne, J.C. (1982) Cytology and leafspot resistance in Arachis hypogaea x wild species hybrids. Euphytica, 31 (3). pp. 885-893.

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Introgression of germplasm from diploid wild Arachis species to A. hypogaea has great potential for improving pest resistance in cultivated peanuts. This investigation evaluated methods for incorporating exotic germplasm into cultivated peanuts, especially for Cercospora arachidicola Hori resistance. Interspecific hybrids between A. hypogaea (cvs. NC 2 and NC 5) and the wild species A. cardenasii Krap. et Greg. nom. nud. and A. chacoense Krap. et Greg. nom. nud. were analyzed cytologically and for leafspot resistance. All F1 hybrids were sterile, had irregular meiosis, and very few multivalents. They were highly resistant to C. arachidicola in field tests and had a 10-fold reduction of conidia per lesion in the greenhouse as compared to A. hypogaea cultivars. After colchicine treatments of F1 hybrids, hexaploids (2n=60) and aneuploids (2n=54, 56, 63) were observed. The hexaploids had up to 18 univalents per pollen mother cell and very few multivalents, indicating a low frequency of intergenomic chromosome pairing. For C. arachidicola resistance, significant differences were not found among wild species parents, F1 hybrids and two generations of hexaploids. Most hexaploids were stable at 2n=60 and embryos aborted when backcrosses with the respective wild species were attempted. However, when hexaploids were backcrossed to A. hypogaea, several fertile pentaploid (2n=50) offspring were obtained. Use of self-pollinating pentaploids is believed to be the quickest method to recover 40-chromosome hybrid derivatives in these hybrids.

Item Type: Article
Additional Information: SNNigam Collection
Uncontrolled Keywords: Arachis hypogaea, Groundnut, Peanut, Interspecific hybrids, Cercospora arachidicola, Leafspot
Author Affiliation: Dept.of Crop Science, N. C. State University, North Carolina, USA
Subjects: Plant Protection
Crop Improvement
Divisions: Groundnut
Depositing User: Mr Arbind Seth
Date Deposited: 26 Apr 2013 04:57
Last Modified: 26 Apr 2013 04:57
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