Roots are critical for plants to withstand environmental abiotic and biotic stresses. Wild taxa are often used as source of variation for improving root systems, as they are adapted to more stressful soil environments than their cultivated relatives. We studied the genetics of traits related to root biomass, root length, and root architecture (considering the primary/secondary and the tertiary root levels) in melon (Cucumis melo L.) in a 2-year assay by examining the root systems of mature plants in 91 F3 families derived from the cross between a wild accession, Pat 81 [C. melo ssp. agrestis (Naud) Pangalo], and a cultivated accession, `Piel de sapo' (C. melo ssp. melo L.). Despite the difficulties of working with adult plants, we found that Pat 81 and `Piel de sapo' differ greatly in their mature root systems, which is in concordance with the results previously obtained with young roots. Pat 81 developed roots with less biomass than `Piel de sapo', but this wild accession had more favorable root length and architectural traits: a higher density of framework roots, more uniformly distributed along the soil profile, longer laterals with a higher density of branches, and a higher number of root orders. This root structure is linked to a deeper rooting ability and to the capacity of exploiting a larger soil volume. The genetic analysis indicated that length and architectural traits are more stable than biomass traits, both between years and between developmental stages. Moderate to low broad- and narrow-sense heritabilites were found for root length and architectural traits, with most of the observed variation due to additive effects. Our results suggest that Pat 81 could be used as donor of valuable genes for increasing root length and improving the root architecture of cultivated melons, producing melons potentially more tolerant to soil stresses. The lack of phenotypic and genetic correlations between length and architectural parameters and root biomass suggest that root structure can be successfully improved without increasing carbon expenditures.
cultivars of stokes aster were selected from natural populations, gardens, or nursery production fields, thus a formal pedigree is lacking for these cultivars. The current understanding of the genetics and biochemistry of flower color of stokes aster is
177 ORAL SESSION (Abstr. 701-708) CROSS-COMMODITY GENETICS III
177 ORAL SESSION (Abstr. 701-708) CROSS-COMMODITY GENETICS III
Abstract
A questionnaire on genetics and breeding of horticultural crops, in conjunction with our responsibilities to the National Plant Genetics Resources Board (an advisory board to the Secretary of Agriculture under authority of Secretary’s Memorandum 1875 Revised dated 23 Feb. 1978), was sent to appropriate department chairmen or program leaders in Land Grant Universities, 1890 institutions, and the USD A Agricultural Research Service (ARS). The purpose of the questionnaire was to survey past, present, and anticipated programs on breeding and genetics of horticultural crops and to solicit views on national needs for germplasm of horticultural crops. Responses on the status of programs were received from all 98 questionnaires, and 74 respondents made comments on national needs.
56 ORAL SESSION 10 (Abstr. 457-464) Cross-commodity: Genetics & Breeding
Dahlgren, K.V.O 1921 Vererbungsversuche mit einer buntblättrigen Barbarea vulgaris Hereditas 2 88 98 Downing, A.J 1857 Fruits and fruit-trees of America 328 329 Wiley and Halsted New York, NY, USA Eyster, W.H 1934 Genetics of Zea
126 ORAL SESSION 39 (Abstr. 276-283) Vegetables: Breeding and Genetics
101 POSTER SESSION 3A (Abstr. 127–158) Breeding & Genetics–Vegetables