Phytopthora, Fusarium and Ralstonia diseases of Horticulture & Agricultural Crops

Abstract

Not AvailableTrue-hybrid nature of F1 of crosses between Nira and wild species was confirmed through morphological and cytogenetic studies. Two types of F1 hybrids: true and partial were obtained in Nira x C.lanatus, Nira x C.creticus, Nira x C. turkestanicus, Nira x C. glaucus crosses. True hybrids were male-female sterile due to cytogenetic abnormalities while partial hybrids resembling mostly C. tinctorius were fertile with perfect meiosis. These were segregated into wilt resistant and susceptible in F1 and F2. Wilt resistance in these crosses confirmed introgression of wild species’ genome into susceptible C. tinctroius (Nira). F2 generations of the interspecific crosses viz., Nira x C. oxyacantha, Nira x C. palaestinus, Nira x C.lanatus, Nira x C.creticus, Nira x C. turkestanicus and Nira x C. glaucus were phenotyped for Fusarium wilt resistance in wilt sick plot along with F2 of the cross between wilt susceptible C.tinctorius x wilt resistant C.tinctorius (Nira x 96-508-2-90).Wilt resistance was found to be controlled by monogenic dominant gene in Nira x C.oxyacantha and Nira x 96-508-2-90 whereas it was by two complementary genes in other crosses. A total of 107 ESSR markers out of 306 were found to polymorphic between cultivated and wild species. Of which, 43 ESSRs were polymorphic between Nira and C. oxyacantha, 17 were polymorphic between Nira and C. palaestinus, six were polymorphic between Nira and C. lanatus,11 were polymorphic between Nira and C. creticus, nine were polymorphic between Nira and C. glaucus,seven were between Nira and C.turkistanicus,11 were between Nira and 96-508-2-90 (C. tinctorius). Bulk segregant analysis (BSA) was done in F2 generation of Nira x-C. oxyacantha and Nira x 96-508-2-90. ESSR markers co-segregating with wilt resistance in Nira x C. oxyacantha and Nira x 96-508-2-90 were identified. A total of 288 F2 plants of Nira x 96-508-2-90 were screened with the identified markers. The markers have amplified in all the resistant F2 plants of this cross. The markers data and phenotypic data were in association with each other.