No description available.

A series of field trials were performed in order to compare the yield stability of plants of the independent vascular supply (IVS) type peduncle vascular architecture with those of the more usual branched type. The IVS plants gave a low stable, source-limited yield; the plants attained maturity four weeks earlier than those of Maris Bead. The source-sink relationships of the genotypes investigated were established. The potential values of IVS type plants as commercial varieties are discussed. Studies of the growth and development revealed a difference in pod wall structure and the distribution of stomata and pod hairs: this could be related to pod drying. The growth of all parts of the raceme was studied by plotting fresh and dry weight changes, a sequence of development of tissues was established, the peduncle growing first, then the pedicel, then the pod and finally the seed. Genotypic differences in growth rate were observed. These findings were related to the accompanying vascular development within the raceme. The source of the assimilates rapidly translocated into the seeds during early, rapid growth was established. The results obtained are discussed and an ideotype constructed on the basis of the information obtained.

Nutritional aspects of size-related sex differences in the diets of free-living mink were investigated in laboratory-based feeding trials with adult farm-bred mink maintained on 'natural' diets. As preliminary studies had shown that carcase utility was virtually complete, the rations presented comprised the minced whole carcasses of wild rabbit Oryctolagus cunniculus, eel Anquilla anguilla, laboratory rats and mice, and domestic fowl. Determinations of gross composition revealed significant differences between these diets; the smaller prey types, including rodents, birds and fish, were found to have a higher ratio of Apparent Digestible Energy to Nitrogen than larger items such as rabbits, although comparisons with data presented by other workers demonstrated that the variations between species within these prey groups are as great as, or greater than, those between the diets themselves. From the results of the feeding trials, it was also apparent that such diets do not differ significantly, either in digestibility or biological value and attempts to classify particular prey items in terms of their nutritional value are, therefore, of limited application in analyses of the feeding ecology of a generalist predator. Nutrient intake was related to diet composition and varied widely between trials, although the mass-specific requirements of females were higher than those of males. Comparisons of gut morphology indicated that, in females, hypertrophy of the alimentary tract may develop in response to increased energy demands. A similar adaptation was evident in both males and females from wild populations, suggesting that the natural diets of free-living mink are generally of a lower quality than the rations fed to commercially raised animals. Feeding trials were also carried out on growing kits from 56 to 105 days post partum. Sex differences in nutrient metabolism were not significant but the growth rates of males were higher than those of females. In both sexes the growth rates of kits feeding on 'natural' diets were lower than those of animals raised on commercial rations. This effect was most pronounced in males, a finding which supports the hypothesis that the degree of sexual dimorphism in this species is dependent on the extent to which the growth potential of males is constrained by dietary regime during the early phases of development.

No description available.

Haplodiploid Hymenoptera females control the sex of their progeny, and their sex allocation is influenced by several factors. The impact of intra- and interspecific competition and of inbreeding and outbreeding on sex allocation has been studied in some species of the egg parasitoid Trichogramma. The pre-mating dispersion has also been studied. Impact of competition on sex allocation was observed for Trichogramma minutum Riley and Trichogramma pintoi Voegele. These species were chosen because of the ease with which than can be distinguish. Results show that females of both species lay more males under intraspecific competition than alone, following the Local Mate Competition theory, while only T. pintoi modifies its sex ratio under interspecific competition. Multiparasitism and natural habitat could explain this shift in the sex ratio. Trichogramma minutum, T. pintoi and Trichogramma evanescens Westwood pre-mating dispersion show that most matings occur at the emergence site. However, the three species have a potential for off-patch mating, allowing genetic exchange between sub-populations. These three species were chosen because they are classified in different groups in the genus. Finally, T. evanescens did not modify its sex ratio following inbreeding or outbreeding. The incapacity to discriminate between kin and non-kin, insufficient genetic distance in outbreeding, or the population structure could explain these results.

No description available.

This study evaluated the effects of dietary starch on productive and reproduction parameters of postpartum dairy cows. Three diets were fed, with increasing starch levels from calving until 70 days in milk. Treatment had no effect on dry matter intake, energy balance, specific metabolic hormones and metabolites, milk yield, or milk components with the exception that cows fed the low starch diet had higher levels of milk urea nitrogen. Cows fed the high starch tended to lose less body condition, had a shorter interval from calving to first ovulation, and a higher incidence of double first ovulations. There were no treatment effects on ovarian dynamics, luteinizing hormone, progesterone or estradiol concentrations. Number of cows confirmed pregnant 30 d after first insemination did not differ between treatments. Increasing dietary starch decreased the interval from calving to first ovulation, but had no impact on productivity and metabolic status of the postpartum cow. / Animal Science

Thesis (Ph.D.)--University of Hawaii at Manoa, 1991. / Includes bibliographical references (leaves 169-179) / Microfiche. / xviii, 179 leaves, bound ill. 29 cm

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 109-111). / Microfiche. / ix, 113 leaves, bound ill. 29 cm

Thesis (Ph. D.)--University of Hawaii at Manoa, 1996. / Includes bibliographical references (leaves 161-182). / Microfiche. / xii, 190 leaves, bound ill., photos. (some col.) 29 cm