Genetic Blocks in the Synthesis of Coumarin in \u3ci\u3eMelilotus alba\u3c/i\u3e

The influence of the two genes, cu and b upon the level and form of coumarin in sweetclover leaf tissue was determined by assaying 25 sweetclover plants of each of the four homozygous genotypes, CuCuBB, CuCubb, cucuBB, and cucubb. An assay of alfalfa leaves provided an indication of the magnitude of fluorescence not ascribable to coumarin. Approximately 0.2 percent total coumarin (dry weight basis) was found in plants homozygous for cu, which is 11.5 times the amount found in alfalfa, but only about 1/20 of the level found in CuCu plants. Thus, the cu-effected block in coumarin synthesis is partial rather than complete. However. the action of the b gene in blocking the formation of free coumarin is virtually complete, as shown by the extremely low levels of free coumarin in bb plants. The probable relationship of bound coumarin, free coumarin and the cu and b genes is shown. Important implications in sweetclover breeding, and in other studies are indicated

Translocation of Coumarin Across a Graft Union m Sweetclover

Despite several recent investigations of the biosynthesis of coumarin and related compounds in sweetclover, little is known of the site or sites within the plant at which coumarin is formed. Weygand and Wendt reported coumarin formation in root cultures of Melilotus officinalis (L.) Lam. when suitable precursors were supplied. Mothes and Kala concluded that scopoletin and umbelliferone, compounds closely related to coumarin, can be synthesized by root cultures of Atropa belladonna L. The experiments cited gave no indication that the roots are the preferred site of synthesis or that synthesis takes place at all in the roots of intact plants. Neither of the studies excluded the possibility of synthesis in other organs

Translocation of Coumarin Across a Graft Union m Sweetclover

Despite several recent investigations of the biosynthesis of coumarin and related compounds in sweetclover, little is known of the site or sites within the plant at which coumarin is formed. Weygand and Wendt reported coumarin formation in root cultures of Melilotus officinalis (L.) Lam. when suitable precursors were supplied. Mothes and Kala concluded that scopoletin and umbelliferone, compounds closely related to coumarin, can be synthesized by root cultures of Atropa belladonna L. The experiments cited gave no indication that the roots are the preferred site of synthesis or that synthesis takes place at all in the roots of intact plants. Neither of the studies excluded the possibility of synthesis in other organs

Registration of N30-N56, N741, N743, N745, N747, U362, U363, U367, U369-U374, U389-U394, U396-U398, and U500 Sweetclover Genetic Stocks

Forty-nine white-flowered sweetclover (Melilotus alba Medik.) genetic stocks [N30-N45 (Reg. GS-1–16, PI 549120–549135); N46-N53 (Reg. GS-17–24, PI 557503–PI 557510); N54-N55 (Reg. GS-25–Reg. GS-26, PI 629289–PI 629290); N741, N743, N745, N747 (Reg. GS-27–GS-30, PI 557511–PI 557514); U362, U363, U367 (Reg. GS-31, Reg. GS-32, Reg. GS-33, PI 557515–PI 557517); U369-U374 (Reg. GS-34–GS 39, PI 557518–PI 557523); U389-U394 (Reg. GS-40–GS 45, PI 557524–PI 557529); U396- U398 (Reg. GS-46–GS 48, PI 557530–PI 557532); U500 (Reg. GS-49, PI 557533)] (Table 1); and N56 (Reg. no. GS-50, PI 634019), a yellow-flowered sweetclover [Melilotus officinalis (L.) Lam.] genetic stock, were developed jointly by USDA- ARS and the Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln and were jointly released in May 2004. The genetic stocks, which contain unique combinations of genes and traits, were developed over more than three decades of cooperative sweet- clover genetic research

Genetic Studies of Induced Mutants in \u3ci\u3eMelilotus alba\u3c/i\u3e III. Folded Leaflet, Elongatyed Stem, and Short-Petiole Dwarf

Observations of the F1, F2, and F3 progenies of crosses between normal annual Melilotus alba Desr. and three mutants, folded leaflet, elongated stem, and short-petiole dwarf, indicate that each of the mutant characters is controlled by a single recessive gene. Proposed symbols for the three mutant genes are f, el, and dsp, respectively. In limited tests for linkage, el appeared to be linked (12% recombination) to a gene for multifoliolate leaves (Mf). No linkage was detected between f and Mf, cu (low o-hydroxycinnamic acid), or b (low β-glucosidase activity)

Inheritance of Flower Color in Musk Thistle (\u3ci\u3eCarduus thoermeri\u3c/i\u3e)

Four flower-color phenotypes were observed in a population of musk thistle (Carduus tboermeri Weinm.). This plant has been commonly referred to as C. nutans L. The four phenotypes were: purple corolla and purple pollen, pink corolla and white pollen, white corolla and purple pollen, and white corolla and white pollen. In four generations, 177 self-pollinated individuals of these four phenotypes produced 2123 progeny plants that were classified. Results support the hypothesis that three independent gene pairs were involved in deter- mining the four flower phenotypes. The gene pairs have been designated P/p, W/w, and Pi/pi. It was postulated that all three dominant alleles, P, W, and Pi, must be present to produce both purple corollas and purple pollen. The p allele prevents color development in both corollas and pollen; the w allele eliminates color in corollas but does not affect pollen color; and the pi allele dilutes corolla color from purple to pink and eliminates pollen color. Height measurements of progenies of self-pollinated plants indicated that decreased plant height was associated with inbreeding. On the basis of the evidence presented, the musk thistle plants used in these experiments appear to belong to a single species

Genetic Studies of Induced Mutants in \u3ci\u3eMelilotus alba\u3c/i\u3e. I. Short-Internode Dwarf, Curled Leaf, Multifoliolate Leaf, and Cotyledonary Branching

Information obtained from the F1, F2, and F3 generations of crosses between the normal annual M. alba progenitor line and the four mutants, short-internode dwarf, curled leaf, multifoliolate leaf, and cotyledonary branching, indicates that each character is conditioned by a single pair of alleles. The multifoliolate leaf character is dominant over the normal phenotype; the other three mutant characters are recessive. The symbols dw, cl, Mf, and cb are proposed as designations for the respective mutant genes

Registration of N30-N56, N741, N743, N745, N747, U362, U363, U367, U369-U374, U389-U394, U396-U398, and U500 Sweetclover Genetic Stocks

Forty-nine white-flowered sweetclover (Melilotus alba Medik.) genetic stocks [N30-N45 (Reg. GS-1–16, PI 549120–549135); N46-N53 (Reg. GS-17–24, PI 557503–PI 557510); N54-N55 (Reg. GS-25–Reg. GS-26, PI 629289–PI 629290); N741, N743, N745, N747 (Reg. GS-27–GS-30, PI 557511–PI 557514); U362, U363, U367 (Reg. GS-31, Reg. GS-32, Reg. GS-33, PI 557515–PI 557517); U369-U374 (Reg. GS-34–GS 39, PI 557518–PI 557523); U389-U394 (Reg. GS-40–GS 45, PI 557524–PI 557529); U396- U398 (Reg. GS-46–GS 48, PI 557530–PI 557532); U500 (Reg. GS-49, PI 557533)] (Table 1); and N56 (Reg. no. GS-50, PI 634019), a yellow-flowered sweetclover [Melilotus officinalis (L.) Lam.] genetic stock, were developed jointly by USDA- ARS and the Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln and were jointly released in May 2004. The genetic stocks, which contain unique combinations of genes and traits, were developed over more than three decades of cooperative sweet- clover genetic research