caa a22 4500 477135404 CHVBK 20180405111716.0 cr unu---uuuuu 170330e19970501xx s 000 0 eng 10.1023/A:1002988003402 doi (NATIONALLICENCE)springer-10.1023/A:1002988003402 Resistance to cowpea severe mosaic virus, determined by three dosage dependent genes in Vigna unguiculata L. Walp [Elektronische Daten] [Pathmanathan Umaharan, Rasiah Ariyanayagam, Syed Haque] P1, P2, F1, F2, BC1 and BC2 generations of four resistant × susceptible crosses and three resistant × resistant crosses of cowpea (Vigna unguiculata L. Walp) were screened for resistance to cowpea severe mosaic virus (CPSMV), in an insect protected screen house. The segregation ratio, at maturity, showed a 63 susceptible : 1 resistant ratio in the F2 generation indicating that resistance is governed by three major genes. The backcross tests and the F3 test confirmed this. The intermediate levels of symptoms observed in the F1 generation and the progression of symptom expression in the F2 generation suggested that resistance is gene dosage dependent. The genetic basis of immunity, tolerance, high level of resistance is discussed based on the three gene model. Delayed symptom expression was evident in genotypes with one or two susceptible alleles. The implications of delayed expression of symptoms in selection and breeding for resistance to CPSMV are discussed. Kluwer Academic Publishers, 1997 cowpea severe mosaic virus nationallicence genetics nationallicence selection nationallicence screening nationallicence resistance nationallicence tolerance nationallicence Vigna unguiculata nationallicence Umaharan Pathmanathan Department of Plant Science, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago aut Ariyanayagam Rasiah Department of Plant Science, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago aut Haque Syed Department of Plant Science, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago aut Euphytica Kluwer Academic Publishers 95/1(1997-05-01), 49-55 0014-2336 95:1<49 1997 95 10681 https://doi.org/10.1023/A:1002988003402 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1002988003402 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Umaharan Pathmanathan Department of Plant Science, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago aut NATIONALLICENCE 700 1- Ariyanayagam Rasiah Department of Plant Science, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago aut NATIONALLICENCE 700 1- Haque Syed Department of Plant Science, The University of the West Indies, St. Augustine, Republic of Trinidad and Tobago aut NATIONALLICENCE 773 0- Euphytica Kluwer Academic Publishers 95/1(1997-05-01), 49-55 0014-2336 95:1<49 1997 95 10681 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer