No description available.

Fundamental genetic studies have application in the breeding and improvement of crop plants. There is a deficiency of this knowledge in birdsfoot-trefoil (Lotus corniculatus L.). Cytogenetic principles have contributed a lot to the improvement of wheat, corn and several other crop plants. Similar studies can be undertaken with birdsfoot-trefoil. So far, few intensive investigations have been carried out in this crop since its potentiality as a forage crop has been recognized only recently. Dawson (1941), Bubar (1957), Donovan (1959), Hart and Wi1sie (1958), Buzzell and Wilsie (1963) found tetrasomic and disomic inheritance in birdsfoot-trefoil. Inheritance studies are important in order to understand the segregation of characters, to bui1d up genetic stocks which may be used in breeding of a crop, and to determine the percentage of natura1 crossing by distinguishing selfs from crossed progenies in a population. [...]

Some 7,500 seeds of Lotus corniculatus cv. Mirabel were treated with X-rays (3,000-12,000 Rads), ethyl methanesulfonate, 8-ethoxycaffeine, n-hydroxyurea, and 2-aminopurine (0.001 to 1.0% solutions). A total of 93 selfed, partially inbred, and open-pollinated lines, comprising some 22,000 plants, were generated over four generations. Mutagenic effects were assessed on germination, seedling survival, meiotic aberrations, pollen abortion, seed and forage yields, pod dehiscence, winter hardiness, brown floral keel tip color, and cyanoglycoside (HCA) content in the leaves. Dose effects were largely confined to the M(,1) generation. Germination and seedling survival could not be used to predict mutation rates. Higher levels of forage and seed yields and lower levels of HCA content were induced. Pod dehiscence, winter hardiness and brown keel tip frequency were not affected. Three qualitative mutants, chlorotica, vestigial floret, and dwarf, were tetrasomic recessives. Only tetrasomically inherited characters were found. X-rays and EMS were the most effective mutagens.

No description available.

No description available.

Birdsfoot Trefoil (Lotus corniculatus L. cv. Leo), is a perennial forage legume that has difficulty in establishing stands due to slow seedling growth, weed competition and herbicide sensitivity. The development of herbicide resistant cultivars would be of economic importance. Resistant lines were isolated after sequential selection at the callus, shoot and whole plant levels to the sulfonylurea (SU) herbicides Harmony (DPX-M6316, code name for methyl 3- ( ( ((4-methoxy-6-methyl-1,3,5,triazine-2-yl)amino) carbonyl) amino) sulfonyl-2-thiophenecarboxylate), or Classic (DPX-F6025, code name for 2(( (4-chloro-6-methoxypyrimidine-yl)amino carbonyl) aminosulfonyl)benzoic acid ethyl ester. In field and growth chamber tests the Harmony regenerant lines displayed an increased tolerance as compared to control plants from tissue culture, and from seed. Results of the evaluation of callus cultures of regenerated mutant lines signify stability of the resistance. Outcrossed seeds collected from field trials, and tested in vitro for herbicide resistance, indicate that the trait is heritable and that resistance may be due to reduced sensitivity of acetolactate synthase to SU inhibition. It is concluded that herbicide resistant birdsfoot trefoil cultivars can be isolated using in vitro selection.

An isoenzyme survey of several taxa within the genus Lotus was undertaken to provide markers for genetic research and to test hypotheses concerning the phylogenetic origin of Lotus corniculatus L. A preliminary study identified seven enzyme systems PGI, TPI, PGM, MDH, IDH, 6-PGDH and ME, that produced consistent clear phenotypes in L. uliginosus Schkuhr. Variation in phenotype with tissue type and stage of development suggested the presence of several isozyme zones in the phenotypes. Enzyme phenotype was constant for shoot tissue of plants older than six weeks. A second study examined recombination and segregation of isoenzyme phenotypes in interspecific hybrids, allo- and autopolyploids, and in L. corniculatus. Duplication and quadruplication of pgi2 loci in hybrids, amphidiploids, and in L. corniculatus was used as evidence that the latter is a segmental allotetraploid. A third study surveyed the occurrence of various isoenzyme alleles in L. alpinus Schleich., L. japonicus (Regel) Larsen, L. tenuis Waldst. & Kit., L. uliginosus and L. corniculatus. Lotus uliginosus had unique distinct alleles for several enzymes that did not occur in the other species. This evidence argues against the involvement of L. uliginosus in the origin of L. corniculatus.

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 219-227).

Thesis (M.S.)--University of Wisconsin--Madison, 1950. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 211-253).