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  • Author or Editor: D.L. Francis x
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Thirty-two tomato (Lycopersicon esculentum Mill.) or L. pimpinellifolium (L.) Mill. accessions were inoculated with race T2 of Xanthomonas campestris pv. vesicatoria (Xcv) in a field experiment at Wooster, Ohio, in 1995. Plants from accessions which segregated for race T2 resistance in greenhouse tests were selected and these are designated by hyphenated extensions below. The eight most resistant accessions from 1995 and PI 262173 were retested in 1996. Lycopersicon esculentum accession PI 114490-1-1 had virtually no Xcv symptoms either year. Lycopersicon pimpinellifolium accessions LA 442-1-Bk and PI 128216-T2 expressed a high level of resistance in 1995, but only partial resistance in 1996. Accessions with partial resistance for both seasons were PI 79532-S1, PI 155372-S1, PI 126428, PI 271385, PI 195002, PI 262173, Hawaii 7998, and Hawaii 7983. PI 79532-S1 is a L. pimpinellifolium accession and the remaining seven are L. esculentum. Twenty accessions tested in 1995 for T2 plus 10 other accessions were also tested for race T1 resistance in Presidente Prudente, Sao Paulo, Brazil, in 1993. Hawaii 7983, PI 155372-S1, PI 114490, PI 114490-S1, and PI 262173 had greater resistance to T1 than the susceptible control, `Solar Set'. Comparisons with earlier experiments, in which accessions were inoculated with race T1 or T3, indicated that the most consistent source of resistance to all three races was PI 114490 or selections derived from it.

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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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