Screening of Psidium species and their interspecific hybrid progenies for resistance to Fusarium oxysporum f. sp. psidii and southern root-knot nematode
Pradeep Kumar Vishwakarma, C. Vasugi, R. Umamaheswari, S. Sriram, P. Nandeesha, M. Sankaran, K.S. Shivashankara
Abstract
• P. cattleianum var. cattleianum, P. cattleianum var. lucidum and P. friedrichsthalianum identified as source of resistance to guava wilt ( Fusarium oxysporum f. sp. psidii ) and root-knot nematode ( Meloidogyne incognita ) infection. • The segregation ratio of susceptible to resistant for guava wilt in interspecific hybrid progenies can provide insight into the mode of inheritance of wilt resistance in guava. • Resistant interspecific hybrid progenies have been developed and can be used as a rootstock or scion. Guava wilt ( Fusarium oxysporum f. sp. psidii ) and root-knot nematode ( Meloidogyne incognita ) are the major threats for guava cultivation in India. The disease complex of Fusarium and Meloidogyne has caused severe production losses throughout India. The present study aimed the identification of resistant sources in wild Psidium species, genotypes and F 1 interspecific hybrids. Six wild Psidium species ( P. molle, P. guineense, P. chinensis, P. friedrichsthalianum, P. cattleianum var. cattleianum and P. cattleianum var. lucidum ), P. guajava genotypes and interspecific hybrids were screened by challenge inoculation. The results revealed that P. cattleianum var. cattleianum and P. cattleianum var. lucidum were immune to both M. incognita (0 RGI score) and F. oxysporum f. sp. psidii (0% wilting). P. friedrichsthalianum was found to be resistant to both F. oxysporum f. sp. psidii and M. incognita (2 RGI score), while P. molle was found resistant only to wilt (0% wilting). A total of 40 interspecific hybrid progenies (‘Arka Poorna’ x P. cattleianum var. cattleianum, ‘H 12–5’ x P. cattleianum var. cattleianum, ‘Arka Poorna’ x P. cattleianum var. lucidum, ‘H 12–5’ x P. cattleianum var. lucidum ) combined resistance to both F. oxysporum f. sp. psidii and southern root-knot nematode. These progenies have been evaluated for various horticultural traits for its use as scion variety with inbuilt resistance to both wilt and nematode or as a resistant rootstock.