ABSTRACT
A simple and efficient protocol for recurrent somatic embryogenesis and plant regeneration is one of the prerequisites for genetic improvement of guava. An efficient reproducible regeneration somatic embryogenesis protocol was developed in four genotypes of Psidium guajava L. using immature zygotic embryo as starter explant. Somatic embryogenesis induction was obtained on MS basal medium supplemented with 2.0 mgL-1 2, 4-D, 400 mgL-1 L-glutamine, 6% sucrose and 500 mgL-1 Malt extract. Following SE induction different developmental stages of somatic embryos (Globular, heart-shaped, torpedo, cotyledonary) was directly obtained and further recurrent embryogenesis also obtained upon prolonged incubation in induction media. Addition of polyethylene glycol (50 mgL-1) significantly improved the embryos maturation in MS supplemented with and 3% sucrose. The regeneration in MS medium supplemented with BAP (0.5 mgL-1), NAA (0.2 mgL-1), casein hydrolysate (100 mgL-1) and 3% sucrose. High plant regeneration frequency and intensity of somatic embryos (58.5%) obtained. Plant maturation on MS medium supplemented with BAP 2.0 mgL-1 with 2% sucrose. The rooted plants was successfully acclimatize in the greenhouse with a survival rate of 85%. This somatic embryogenesis protocol developed would be helpful in establishment of genetically modified guava aimed at seedlessness, increased shelf life and wilt disease.
ABSTRACT
ABSTRACT Fusarium mangiferae (=F. subglutinans) isolates collect from malformed samples from major mango-growing area of North India. Molecular identification and characterization of eleven most virulent isolates of F. mangiferae, based on pathogenicity tests used for the present study. Species-specific, genus specific ITS-PCR and PCR-RFLP performed for the accurate and easy detection of F. mangiferae. The rDNA-ITS 28S region sequences used for phylogenetic analysis of Fusarium isolates from India and other countries for homology search between them. The phylogenetic tree divided the isolates into three clades (i.e., American, Asian and African) and showed the high level of sequence based similarity (69-99%) among all Fusarium sequences from Asia. Thus, claimed Fusarium mangiferae as dominant pathogen of mango malformation. Furthermore, we conclude that exploiting the nested PCR coupled with PCR-RFLP will help in rapid and accurate detection of F. mangiferae pathogen of mango malformation.