Genetics of fruit quality and resistance to cucumber mosaic virus in Capsicum.

摘要

Ten structural genes of the carotenoid biosynthetic pathway in Capsicum have been localized on an interspecific (C. annuum x C. chinense) F2 linkage map anchored in tomato dispersed across 7 of the 12 chromosomes. The positions of these loci were compared with known structural gene loci in Lycopersicon and loci affecting carotenoid content in Capsicum, Lycopersicon and Solanum. Our positions for these structural genes were found to overlap with phenotypic and quantitative fruit color loci controlling qualitative shifts in fruit color intensity across these genera. These results demonstrate the utility of comparative mapping for linking candidate genes with phenotypically-defined and quantitative loci in related species.;Another group of metabolites, found exclusively in Capsicum, are capsaicinoids, responsible for pungency. While individual capsaicinoids have been found to differ organoleptically, no studies have addressed the possible association between capsaicinoid content and organoleptic differences associated with some genotypes. The four major capsaicinoids from mature pepper fruit were assayed by HPLC and GC. While total capsaicinoid content was found to vary significantly, the ratios of the major capsaicinoids were found to be stable across environments. Differences in the ratios of the major capsaicinoids were identified between some genotypes assayed. No correlation could be established between the ratios of the four major capsaicinoids and different organoleptic properties ascribed to the pepper varieties 'Habanero,' 'Bermejo,' and 'Tepin.';While pepper is affected by a number of pathogens, cucumber mosaic virus (CMV) is particularly devastating, causing severe losses worldwide. Breeding efforts have been hampered due to the complex nature of CMV resistance and few well-characterized sources of resistance. A backcross breeding strategy, used to introgress CMV resistance from'French Perennial,' C. frutescens 'BG2814-6' and 'NuMex Twilight' into the Anaheim, Bell and Jalapeno types is described.;Much of the research conducted at universities is transferred to companies in the private sector. Within R&D intensive industries such as seed companies, various strategies are available to guide business decisions about how to best invest resources. An analysis of the decision making process best suited for companies with a large plant breeding component was conducted using the herbal industry as a model.