Resistance to groundnut rosette disease in wild Arachis species

One hundred and sixteen accessions representing 28 species in the genus Ara chis were evaluated for resistance to groundnut rosette disease using an in fector row technique during the 1996/97, 1997/98, 1998/99 and 1999/2000 gro wing seasons at Chitedze, Malawi. Of these, a total of 25 accessions belong ing to Arachis diogoi (1 accession), A. hoehnei (2), A. kretschmeri (2), A. cardenasii (2), A. villosa (1), A. pintoi (5), A. kuhlmannii (2), A. appre ssipila (3), A. stenosperma (5), A. decora (1), and A. triseminata (1) show ed resistance to the groundnut rosette disease. No visible disease symptoms were observed in several accessions belonging to A. appressipila, A. carde nasii, A. hoehnei, A. kretschmeri, A. villosa, A. pintoi, A. kuhlmannii, an d A. stenosperma. Some accessions in A. appressipila, A. diogoi, A. stenosp erma, A. decora, A. triseminata, A. kretschmeri, A. kuhlmannii, and A. pint oi were resistant to all three components of rosette, Groundnut rosette ass istor virus (GRAV), Groundnut rosette virus (GRV) and its satellite RNA (sa t. RNA). Two accessions in A. stenosperma and one accession in A. kuhlmanni i showed the presence of all three components of the rosette disease. Sever al wild Arachis accessions were resistant to GRAV. All the accessions of A. batizocoi (4), A. benensis (2), A. duranensis (46), A. dardani (1), A. ipa ensis (1), A. magna (1), A. monticola (3), A. oteroi (1), A. pusilla (4), a nd A. valida (2) were susceptible to rosette disease. In all these accessio ns, infected plants were chlorotic and severely stunted. The value of explo itation of the resistance in wild Arachis species in rosette resistance bre eding programmes is discussed.