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  • Author or Editor: Joanne A. Labate x
  • HortScience x
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Broccoli and cauliflower are different botanical varieties of Brassica oleracea. Mutant alleles at the loci BoCAL and BoAP1 can cause arrest at curding that is characteristic of cauliflower. These genes control early floral differentiation, necessary for the progression from a cauliflower-like inflorescence to the flower buds of broccoli. To what extent is the cauliflower-to-broccoli variation within the USDA-PGRU collection determined by mutant alleles of these genes? We surveyed the broccoli collection to examine the correlation between genotype and phenotype. Earlier work showed that BoCAL alone was not an effective predictor of cauliflower phenotype in this collection. The redundant function of BoCAL and BoAP1 in determining inflorescence arrest raises the possibilty that the combined genotype can explain the phenotypic variation. We found that not to be the case. Two accessions varied in phenotype and segregated at both loci, but the combined genotypes were not associated with the expected phenotypes. Two additional accesssion varied in phenotype and segregated at one locus, but with no association between genotype and phenotype. One line varying widely in phenotype was fixed for both loci. One line that was a stable intermediate phenotype segregated for BoCAL. A commercial broccoli cultivar had the cauliflower allele at both loci. The genetic basis of the cauliflower phenotype in the USDA B. oleracea collection is due more to alleles of genes affecting the expression of BoAP1 adn BoCAL than to variation in these alleles of the genes themselves.

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There is a growing interest by consumers to purchase fresh tomatoes with improved quality traits including lycopene, total soluble solids (TSS), vitamin C, and total titratable acid (TTA) content. As a result, there are considerable efforts by tomato breeders to improve tomato for these traits. However, suitable varieties developed for one location may not perform the same in different locations. This causes a problem for plant breeders because it is too labor-intensive to develop varieties for each specific location. The objective of this study was to determine the extent of genotype × environment (G×E) interaction that influences tomato fruit quality. To achieve this objective, we grew a set of 42 diverse tomato genotypes with different fruit shapes in replicated trials in three locations: North Carolina, New York, and Ohio. Fruits were harvested at the red ripe stage and analyzed for lycopene, TSS, vitamin C, and TTA. Analysis of variance (ANOVA) revealed that there were significant differences (P < 0.05) among tomato genotypes, locations, and their interaction. Further analysis of quality traits from individual locations revealed that there was as much as 211% change in performance of some genotypes in a certain location compared with the average performance of a genotype. Lycopene was found to be most influenced by the environment, whereas TTA was the least influenced. This was in agreement with heritability estimates observed in the study for these quality traits, because heritability estimate for lycopene was 16%, whereas that for TTA was 87%. The extent of G×E interaction found for the fruit quality traits in the tomato varieties included in this study may be useful in identifying optimal locations for future field trials by tomato breeders aiming to improve tomato fruit quality.

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