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Anna L. Testen, Delphina P. Mamiro, Hosea D. Mtui, Jackson Nahson, Ernest R. Mbega, David M. Francis, and Sally A. Miller

Tomato is an important cash crop in many developing countries. However, smallholder farmers often lack access to improved cultivars and breeding programs to develop locally adapted cultivars are limited. Participatory crop improvement (PCI) approaches can be used to increase farmer access to improved cultivars. In this project, we used the mother and baby trial (MBT) design to introduce and evaluate tomato cultivars in three villages in the Morogoro Region of Tanzania. Mother trials were conducted in seven environments within the three villages, and variance partitioning revealed significant genetic effects for all traits measured with h 2 ranging from 0.74 to 0.90 for yield and disease reaction, respectively. In baby trials, farmers provided qualitative rankings of cultivars for 16 characteristics, including vigor, yield, harvest period, diseases, insect damage, fruit quality, and salability. Results from baby trials indicated that introduced cultivars were locally acceptable to farmers, except for traits related to marketability. Outcome Mapping was used to evaluate progress in each of the three villages and results suggested that high stakeholder participation levels could predict future adoption of introduced cultivars. Our findings provide a framework for evaluating, selecting, and breeding tomato and other horticultural crops in developing countries using the MBT design for PCI.

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Heidi C. Wernett, Thomas J. Sheehan, Gary J. Wilfret, Francis J. Marousky, Paul M. Lyrene, and David A. Knauft

A broad source of Gerbera × hybrida Hort. germplasm was evaluated for vase life. Senescence mode, i.e., bending or folding of stems or wilting of ligulae was also recorded for flowers evaluated. Intensive selection was practiced to improve vase life. About 10% of the plants from a sample population were selected for having flowers with high vase life. Progeny means for vase life resulting from a topcross between these plants and `Appleblossom' were used to select five plants (about 1.5% of the sample population) whose flowers had high vase life. A diallel cross using these five plants as parents resulted in a progeny population with an increase in mean vase life of 3.4 days compared to mean vase life for the initial sample population. Increases in vase life means for days to bending, folding, and wilting were 0.3, 3.5, and 1.2 days, respectively. Plants with flowers which senesced due to wilting had the longest mean vase life before and after breeding. Changes in proportion of senescence modes were observed; bending decreased, folding and wilting increased. Frequencies of bending, folding, and wilting were compared to vase life means for 10 progenies. Proportion of bending generally decreased as vase life increased.

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Heather L. Merk, Shawn C. Yarnes, Allen Van Deynze, Nankui Tong, Naama Menda, Lukas A. Mueller, Martha A. Mutschler, Steven A. Loewen, James R. Myers, and David M. Francis

For many horticultural crops, selection is based on quality as well as yield. To investigate the distribution of trait variation and identify those attributes appropriate for developing selection indices, we collected and organized information related to fruit size, shape, color, soluble solids, acid, and yield traits for 143 processing tomato (Solanum lycopersicum L.) lines from North America. Evaluation of the germplasm panel was conducted in a multiyear, multilocation trial. Data were stored in a flat-file format and in a trait ontology database, providing a public archive. We estimated variance components and proportion of variance resulting from genetics for each trait. Genetic variance was low to moderate (range, 0.03–0.51) for most traits, indicating high environmental influence on trait expression and/or complex genetic architecture. Phenotypic values for each line were estimated across environments as best linear unbiased predictors (BLUPs). Principal components (PC) analysis using the trait BLUPs provided a means to assess which traits explained variation in the germplasm. The first two PCs explained 28.0% and 16.2% of the variance and were heavily weighted by measures of fruit shape and size. The third PC explained 12.9% of the phenotypic variance and was determined by fruit color and yield components. Trait BLUPs and the first three PCs were also used to explore the relationship between phenotypes and the origin of the accessions. We were able to differentiate germplasm for fruit size, fruit shape, yield, soluble solids, and color based on origin, indicating regional breeding programs provide a source of trait variation. These analyses suggest that multitrait selection indices could be established that encompass quality traits in addition to yield. However, such indices will need to balance trait correlations and be consistent with market valuation.