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ornamental potted plant and outdoor gardening ( Lakshminarayana and Sujatha, 2001 ). Its flowers are of raceme type with deep red to pink florets setting year-round, whereas fruiting is rare giving small seeds. Interspecific hybridization among both species
White mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, causes major losses in dry and snap bean (Phaseolus vulgaris) production. With little genetic variation for white mold resistance in common bean, other potential sources for resistance must be investigated. Accessions of scarlet runner bean (P. coccineus) have been shown to have partial resistance exceeding any to be found in common bean. Resistance is quantitative with at least six QTL found in a P. coccineus intraspecific resistant × susceptible cross. Our goal is to transfer high levels of resistance from P. coccineus into commercially acceptable common bean lines. We developed interspecific advanced backcross populations for mapping and transfer of resistance QTL. 111 BC2F5 lines from a cross between OR91G and PI255956 have been tested in straw tests and oxalate tests, as well as in a field trial. The data show that the OR91G × PI255956 population carries a high level of resistance, but because of the quantitative nature of resistance, it may be necessary to intercross individuals to achieve higher levels. SSR, RAPD, and AFLP markers are being tested in the population to construct a linkage map for placement of QTL. QTL identified from each type of test (straw, oxalate, and field) may provide additional information about the genetic architecture of white mold resistance. Three other populations are from advanced backcrosses of the recurrent parents G122, OR91G, and MO162, with PI433251B as the donor parent in each. Analyses and advance of these populations will follow, the results of which should confirm QTL identified in the OR91G × PI255956 population, as well as possible additional resistance QTL from PI433251B.
Crossing barriers between white- and purple-flowered species were examined. Four accessions of Capsicum annuum and three of C. pubescens were reciprocally crossed with one to four accessions of C. baccatum, C. cardenasii, C. chacoense, C. chinense, C. eximium, C. frutescens, C. galapagoense, and C. praetermissum. Capsicum chacoense is the only white-flowered species that inhibits C. annuum pollen tube growth but allows C. pubescens pollen tube penetration into the egg cell. Capsicum cardenasii and C. eximium exhibit similar crossabilities with C. annuum and C. pubescens: pollen tubes of C. cardenasii and of C. eximium can penetrate the egg cells of C. annuum but not vice versa, and pollen tubes of C. pubescens can penetrate the egg cells of C. cardenasii and of C. eximium but not vice versa.
Abstract
Putative hybrids of P. floribunda (Pursh ex Sims) Benth. and Hook, and P. japonica (Thunb.) D. Don ex G. Don were produced but most were short-lived. Morphological traits of 4 of these surviving hybrids were intermediate to the parent species; the hybrids also were sterile and lacked merit as cultivar selections. P. phillyreifolia (Hook.) DC. failed to cross successfully with either P. floribunda or P. japonica.
attempted to use variability in the genus for crop improvement through interspecific breeding yet overcoming crossing barriers, the male sterility, and incompatibility of the interspecific F 1 and early succeeding generations of distant crosses has been a
. Interspecific and intergeneric crosses were made as species came into bloom beginning in July 2012 and ending in Mar. 2013. Flowers were emasculated to prevent self-pollination. Emasculations were carried out before anthers had completely unfolded when possible
2006, 2007, and 2008 using standard horticultural practices. Forty-three interspecific crosses were completed in a greenhouse with at least four pollinated inflorescences per cross. The greenhouse was screened to exclude insect pollinators. All
). However, hybridization readily occurs between species of Baptisia ( Alston and Turner, 1963 ; Baetcke and Alston, 1968 ; Dement and Mabry, 1975 ; Larisey, 1940 ; Leebens-Mack and Milligan, 1998 ). In the genus Baptisia , interspecific crosses have
. A high degree of fertility was apparently maintained throughout initial crosses between the two species and various combinations of progeny. Other interspecific crosses incorporated into the L. indica × L. fauriei breeding program include L
hybrids. A hybrid with commercial potential was produced through ovule culture from the cross H. scandens ssp. chinensis to H. macrophylla , although the hybrid was sterile ( Kudo et al., 2008 ). Unlike most of the interspecific hybrids, the